Rusts

Els uredinals (Uredinales) o Puccinals (Puccinales) són un ordre de fongs de la classe dels urediniomicets (Urediniomycetes). Més del 95% de les espècies i 75% dels gèneres dels urediniomicets pertanyen a l'ordre dels uredinals.

S'estima que hi ha uns 168 gèneres i unes 7.000 espècies, més de la meitat de les quals pertanyen al gènere Puccinia.^[1] Els fongs de rovell (en anglès: rust fungi) són paràsits altament especialitzats amb diverses característiques úniques. na sola espècie pot produir fins a cinc estructures diferents que produeixen espores (espermagònia, aecis, uredinis, telis i basidis) en estadis successius de reproducció. Normalment afecten plantes sanes i vigoroses i la infestació es redueix a parts de les plantes.^[1] Les plantes afectades poden presentar clorosi. Poden tenir un primer hoste (per exemple plantes del gènere Juniperus) i un segon hoste (per exemple la perera)

Particularitats

Popularment els uredinals es coneixen com a rovell. Aquests fongs són paràsits que poden causar desperfectes greus a l'agricultura. Plantes com el blat i el xenixell són molt vulnerables als rovells.

El rovell és una de les espècies vegetals esmentades al Nou Testament, Mat. 6:19:

"No aplegueu riqueses sobre la terra, on l'arna i el rovell les destrueixen, i on els lladres entren i les roben.

Famílies

Aquests fongs es troben agrupats en les següents famílies:

• Chaconiaceae
• Coleosporiaceae
• Cronartiaceae
• Melampsoraceae
• Micronegeriaceae
• Phakopsoraceae
• Phragmidiaceae
• Pileolariaceae
• Pucciniaceae
• Pucciniastraceae
• Raveneliaceae
• Sphaerophragmiaceae
• Uncolaceae
• Uropyxidaceae

Enllaços externs

En altres projectes de Wikimedia: Commons Viquiespècies

• Imatges de rovells

Referències

Rzi (Uredinales, Pucciniales) je skupina parazitických stopkovýtrusných hub, řazená například jako řád do třídy Urediniomycetes čili Pucciniomycetes.^[1][2][3]

Popis

Jedná se o obligátní parazity rostlin, tvořící podhoubí čili mycelium. Mají poměrně složitý životní cyklus a jsou schopné střídat hostitele, ačkoliv se pravděpodobně řadí mezi nejjednodušší stopkovýtrusné houby (mají přepážky hyf obvykle bez přezek a dolipor, dlouhou haploidní fázi, primitivní typ rozmnožování a podobně).^[2]

Životní cyklus

Jednojaderné stadium je na poměry obvyklé u hub velice rozvinuté a dokonce může převažovat nad dvoujaderným. Mycelium s jednojadernými buňkami vyroste z bazidiospory a je schopné následně proniknout i dovnitř buněk hostitele, kam obvykle vysílá větvící se haustoria. Pletivo rostliny se zbytňuje, získává oranžovou barvu a vytváří se hypertrofie a hyperplazie. Na povrchu listu se nakonec vyvinou pohlavní struktury, spermogonia produkují spermacie a nektar, zatímco tzv. receptivní hyfy vyrůstají z ústí spermogonií. Nektar láká hmyz, ten roznáší spermacie a přenosem spermacií na receptivní hyfu jiného jedince může dojít postupně k plazmogamii a ze vzniklé buňky se začne vyvíjet množství prášilek čili aecií. V nich se vyvíjejí dikaryotické výtrusy, které se šíří větrem a může z nich vyklíčit sekundární (dikaryotické) mycelium. To nese uredia, na nichž vzniká nová řada výtrusů. Tyto tzv. urediospory slouží pouze k rozšíření nákazy na svém hostiteli. Zato tzv. teliospory čili zimní výtrusy vznikají o něco později na dikaryotickém myceliu a představují klidové stadium, jež po zimě dokončí vývoj, změní se v bazidie a po meióze vzniknou čtyři bazidiospory. Tím se cyklus uzavírá.^[1]

Reference

1. ↑ ^{a b} KALINA, Tomáš; VÁŇA, Jiří. Sinice, řasy, houby, mechorosty a podobné organismy v současné biologii. Praha: Karolinum, 2005. 606 s. ISBN 80-246-1036-1.
2. ↑ ^{a b} http://www.sci.muni.cz/botany/mycology/repetit/vi_basidiomycota-i.pdf
3. ↑ http://www.biolib.cz/cz/taxon/id142463/

Rustsvampene (Uredinales) har fået deres navn efter de rustrøde pletter, der er det første tegn på, at et angreb er i gang. Disse svampe regnes af mange for at være primitive, men arterne har specialiseret sig til at udnytte snævre nicher, nemlig deres værtplanter. Svampene spredes ved hjælp af mange forskellige slags sporer, og det er netop det, som gør det muligt for dem at leve på to forskellige slags planter.

Hos rustsvampene dannes de såkaldte teleutosporer i et firedelt basidium. Desuden dannes der som nævnt også andre sporetyper: uredosporer, pyknidiesporer og aecnidiesporer.

Svampen lever ved at forbruge af værtplantens overskud, og det svækker planten i forskellig grad lige fra det helt ubetydelige til det katastofale. Ved at skifte mellem to forskellige arter omgår svampen det problem, der liggger i risikoen for at dræbe sin vært. Der findes dog også rustsvampe uden værtsskifte.

På vinterværten (som ofte er træagtige planter eller rødderne af stauder) dannes i foråret sporer, som angriber sommerværten (ofte kun blade og unge skud). Her dannes sidst på sommeren en anden type sporer, som angriber vinterværten.

Rustsvampe med tvunget værtskifte

Rustsvamp Sommervært Vintervært Pæregitterrust Pære Sevenbom Pilerust Pil Star Blommerust Blomme Anemone Tjørne-enebærrust Hvidtjørn Enebær Fyrrens blærerust Solbær Fyr

Rustsvampe uden værtskifte

Brombærreust, Chrysanthemumrust, Rosenrust, Stokroserust.

Die Rostpilze oder Rostpilzartigen (Pucciniales, Syn. Uredinales)^[1] sind eine Ordnung der Ständerpilze (Basidiomycota). Sie sind Pflanzenparasiten und befallen vorwiegend Sprossachsen und Blätter. Sie haben einen komplexen Lebenszyklus, der häufig auch Wirtswechsel einschließt. Etliche Vertreter sind von wirtschaftlicher Bedeutung, da sie Nutzpflanzen befallen.

Merkmale und Ökologie

Die Rostpilzartigen leben parasitisch vorwiegend im Apoplast, dem Interzellularraum von Pflanzengeweben. Sie töten das Gewebe dabei nicht ab. Mit Hilfe eines Haustoriums dringen sie in die Wirtszelle ein. Sie bilden ein Myzel, das nur in seltenen Fällen die ganze Wirtspflanze befällt (etwa Uromyces pisi), meist auf das Gebiet um die Infektionsstelle beschränkt bleibt. An den dikaryotischen Hyphen werden keine Schnallen gebildet. Als Geschlechtsorgane bilden sie Spermatien und Empfängnishyphen, die Septalporen sind einfach und sie bilden ausgeprägte Nebenfruchtformen, alles Merkmale, die sie eher mit den Schlauchpilzen als mit den Ständerpilzen verbindet, zu denen sie jedoch gehören. Die Rostpilzartigen bilden keine auffälligen Fruchtkörper, mit nur wenigen Ausnahmen. Dies gilt als Anpassung an die Lebensweise auf den meist kurzlebigen krautigen Organen ihrer Wirtspflanzen.

Die Rostpilzartigen bilden eine große Vielfalt an Sporen, der vollständige Entwicklungszyklus umfasst fünf Sporenarten. Die Abfolge der Sporen ist mit Kernphasenwechsel und häufig auch mit Wirtswechsel verbunden. Der vollständige Zyklus kann unterschiedlich stark reduziert sein.

Ein vollständiger Zyklus kommt beim Getreiderost (Puccinia graminis) vor:

1. Die haploiden Basidiosporen keimen im Frühjahr auf den Blättern des ersten Wirtes aus (hier Berberitze). Es bildet sich ein parasitierendes Myzel, die Zellen sind einkernig (haploid). Jedes dieser Myzelien bildet zwei verschiedene Strukturen: Knapp unter der oberen Blattepidermis des Wirts bilden sie Spermogonien, diese bilden die Geschlechtskerne. An der Blattunterseite bilden sie Aecidienanlagen. Die hier gebildeten Basalzellen nehmen die Geschlechtskerne auf und bilden so das paarkernige Dikaryon. Spermogonien und Aecidienanlagen werden am gleichen Myzel gebildet, eine Selbstbefruchtung wird aber durch Selbstinkompatibilität verhindert: Die Basidiosporen und somit auch die daraus entstehenden Myzele sind bipolar, es gibt (+) und (−)-Hyphen.
2. Die Basalzelle kann auf zwei Wegen ihren zweiten Kern erhalten: Aus dem Spermogonium werden nach dem Durchbrechen der Pflanzenepidermis einkernige Spermatien freigesetzt, die ihren Kern auf eine Empfängnishyphe übertragen. Empfängnishyphen sind querwandlose Hyphen, die über die Blattoberfläche hinausreichen. Gelangt ein Spermatium auf eine Empfängnishyphe, verschmelzen die Zellen und der Spermatienkern wandert durch die Hyphe zur Basalzelle und begründet hier das Paarkernstadium. Die Übertragung der Spermatien wird dadurch gefördert, dass die Spermogonien häufig Nektar absondern und daher von Insekten besucht werden, die die Spermatien auch auf andere Pflanzen übertragen. Der zweite Weg ist die Übertragung des Kerns durch Somatogamie, der nicht beim Getreiderost, aber bei anderen Rosten vorkommt: hier verschmelzen zwei normale Hyphen, eine (+) eine (−), miteinander. Aus der nun zweikernigen Basalzelle bildet sich ein Aecidium, das die Blattunterseite durchbricht und in vielen Ketten dikaryotische Aecidiosporen bildet.
3. Die Aecidiosporen besitzen eine andere Kernphase: sie sind haploid-dikaryotisch. Sie können nur auf bestimmten Wirtsarten keimen, im Falle des Getreiderosts Getreide und andere Süßgräser. Sie bilden einen Keimschlauch, der durch eine Spaltöffnung in den Wirt eindringt und hier interzellulär wächst, jedoch lokal begrenzt bleibt. Das Myzel ist paarkernig, aber schnallenlos.
4. Dieses Myzel bildet in großer Zahl ungeschlechtliche Sporen: Konidien, hier Uredosporen genannt. Sie werden in rostfarbenen Lagern, den sogenannten Uredien, gebildet, die die Blattoberfläche durchbrechen. Die Uredosporen sind die sogenannten Sommersporen und sorgen unter geeigneten Bedingungen für eine massenhafte Verbreitung des Rostpilzartigen: auf einer Pflanze können Millionen Sporen gebildet werden. Aus den Uredosporen entsteht wieder ein haploid-dikaryotisches Myzel.
5. Im Herbst werden in den Uredosporenlagern oder in eigenen Lagern, den Telien, die Überwinterungsformen gebildet, die Teleutosporen. Sie sind zweizellig, haben eine dicke Zellwand und sind gegen Kälte und Trockenheit widerstandsfähig. In ihnen erfolgt die Kernpaarung (Karyogamie), es entstehen zwei diploide Zellen, die Probasidien. Im Frühjahr keimen sie aus, vollführen eine Meiose und bilden eine schlauchförmige Basidie: zwischen die jeweils vier Kerne werden Zellwände eingezogen, aus jeder Zelle bildet sich eine Basidiospore, in die der Zellkern einwandert und dann abgeschleudert wird. Wenn eine Basidiospore auf dem richtigen Wirt landet, beginnt der Zyklus von neuem.

Bedeutung

Die Rostpilzartigen können an Nutzpflanzen wirtschaftlich bedeutenden Schaden anrichten. Getreideernten können bei Befall um bis zu 25 % geringer ausfallen. Der Getreideschwarzrost (Puccinia graminis) ist weltweit verbreitet, richtet aber besonders in wärmeren Ländern Schaden an. Der Gelbrost (Puccinia striiformis) ist in Mitteleuropa besonders für Weizen bedeutsam. Neben Getreide werden verschiedenste Nutzpflanzen wie Spargel, Karotte, Zwiebel von Puccinia-Arten, Erbse, Bohne und Rüben von Uromyces-Arten befallen. Melampsora lini befällt den Gemeinen Lein. Melampsorella caryophyllacearum verursacht Hexenbesen und Krebs an Weißtannen.

Eine Bekämpfung der Zwischenwirte ist meist nicht erfolgreich, da meist auch die Uredosporen überwintern können oder die Wintersaat bereits im Herbst befallen. Uredosporen können zudem über sehr große Entfernungen, selbst über die Alpen hinweg, vom Wind ausgebreitet werden. Resistenzzüchtungen sind aufgrund der großen Zahl von physiologischen Rassen bei den Rostpilzartigen sehr schwierig.

Systematik

Die Schwestergruppe der Rostpilzartigen sind wahrscheinlich die Platygloeales.^[2]

Die Ordnung besteht aus 13 Familien mit rund 115 Gattungen und 7000 Arten.^[3]

Einige Gattungen und Arten:

• Aecidium
  • Aecidium ampliatum
  • Aecidium archibaccharidis
  • Aecidium batesii
  • Aecidium borrichiae
  • Aecidium columbiense
  • Aecidium dahliae
  • Aecidium dahliae-maxonii
  • Aecidium hualtatinum
  • Aecidium ivae
  • Aecidium keerliae
  • Aecidium liabi
  • Aecidium mesadeniae
  • Aecidium mikaniae
  • Aecidium pereziae
  • Aecidium praecipuum
  • Aecidium steviicola
  • Aecidium wedeliae-hispidae

• Cronartium
  • Cronartium flaccidum (ein Auslöser des Kienzopfs)
  • Strobenrost oder Weymouthkieferblasenrost (Cronartium ribicola)

• Endocronartium
  • Endocronartium pini (ein Auslöser des Kienzopf)

• Gymnosporangium
  • Birnengitterrost (Gymnosporangium sabinae)

• Hemileia
  • Kaffeerost (Hemileia vastatrix)

• Melampsora
  • Leinrost (Melampsora lini)
  • Kieferndrehrost (Melampsora populnea)

• Melampsorella
  • Tannenkrebs (Melampsorella caryophyllacearum)

• Ochropsora
  • Ochropsora ariae

• Nyssopsora
  • Nyssopsora echinata

• Uromyces
  • Uromyces pisi

• Puccinia
  • Pflaumenrost (Puccinia discolor)
  • Getreiderost (Puccinia graminis)
  • Malvenrost (Puccinia malvacearum)
  • Puccinia millegranae
  • Puccinia recondita
  • Maisrost (Puccinia sorghi, Syn. P. maydis)
  • Gelbrost (Puccinia striiformis)
  • Braunrost des Weizens (Puccinia triticina)
  • Brennnessel-Rostpilz (Puccinia urticata)

• Pucciniastrum
  • Fichtenzapfenrost (Pucciniastrum areolatum)
  • Tannennadelrost, Fuchsienrost (Pucciniastrum epilobii)

Quellen

Literatur

• Andreas Bresinsky, Christian Körner, Joachim W. Kadereit, G. Neuhaus: Strasburger – Lehrbuch der Botanik. 36. Auflage. Spektrum Akademischer Verlag, Heidelberg 2008, ISBN 978-3-8274-1455-7, S. 674–678.
• Dean, Ralph, et al.: The Top 10 fungal pathogens in molecular plant pathology. In: Molecular Plant Pathology. Band 13, Nr. 4, 2012, S. 414–430, doi:10.1111/j.1364-3703.2011.00783.x.

Einzelnachweise

1. ↑ Mycobank, abgerufen am 26. Oktober 2012
2. ↑ M. Catherine Aime, P. Brandon Matheny, Daniel A. Henk, Elizabeth M. Frieders, R. Henrik Nilsson, Meike Piepenbring, David J. McLaughlin, Les J. Szabo, Dominik Begerow, José Paulo Sampaio, Robert Bauer, Michael Weiß, Franz Oberwinkler, David Hibbett: An overview of the higher level classification of Pucciniomycotina based on combined analyses of nuclear large and small subunit rDNA sequences. In: Mycologia. Band 98, Nr. 6, 2006, S. 896–905, doi:10.3852/mycologia.98.6.896 (englisch, mycologia.org [PDF; 2,6 MB]).
3. ↑ Robert Bauer, Dominik Begerow, José Paulo Sampaio, Michael Weiß, Franz Oberwinkler: The simple-septate basidiomycetes: a synopsis. Mycological Progress, Band 5, 2006, S. 41–66, , doi:10.1007/s11557-006-0502-0.

Weblinks

• Dagmar Nierhaus-Wunderwald: Rostpilze an Fichten. (PDF; 264 kB) In: Merkblatt für die Praxis. 32. Eidgenössische Forschungsanstalt für Wald, Schnee und Landschaft (WSL), 2000, abgerufen am 27. Juli 2012.

Zeng an jeng nexweşiyeke riwekan e. Zeng ji çend cureyên kuvan çêdibe: ew kuvan (bi latînî, Uromyces) û (lat. Puccinia) in. Bi taybetî (lat. Puccinia graminis) ji wan yek û li zêd dixe.

Di kurdî de gelek nexweşî bi navê zengê tê diyarkirin lê hin ji wan ji kuvan çênabin. Riwekê ku zengê xwe avêtî ya reş dibe ya jî gewroxî dibe. Ji ber ku rengî wek rengê zengara hêsin dibe bi vê nexweşiyê re dibêjin zeng.

Bêjenasî

Ev peyv wek ziGghANa di sankrîtî de ye.

Η σκωρίαση στα λατινικά (Uredinalis, «uredio» σημαίνει σφαδάζω εξ ου και η φράση «σφάκελος νόσος»),^[1] είναι ομάδα ασθενειών των σπερματοφύτων οι οποίες οφείλονται σε παρασιτικούς βασιοδιομύκητες, τους σκωριομύκητες, και προκαλούν συχνά ζημιές στις καλλιέργειες. Πήρε το όνομά της από το χρώμα της σκουριάς (σκωρία) που έχουν τα μέρη που έχουν προσβληθεί.

Μετάδοση ασθένειας και αντιμετώπιση

Η ασθένεια μεταδίδεται με σπόρια τα οποία μεταφέρονται από φυτό σε φυτό με τον αέρα ή δονήσεις. Η υγρασία και το νερό ευνοούν την ασθένεια.

Για να προστατευτεί η καλλιέργεια πρέπει να τοποθετείται παράλληλα με τους ανέμους. Επίσης πρέπει τα ήδη προσβεβλημένα φυτά να απομακρύνονται και να καίγονται. Μετά την συγκομιδή μπορούν να γίνουν προληπτικοί ψεκασμοί κάθε 10 – 15 μέρες με μυκητοκτόνα. Αν παρ’ όλα αυτά υπάρξει προσβολή χρησιμοποιούνται διασυστηματικά μυκητοκτόνα.

Το φθινόπωρο απομακρύνεται και καίγεται και το υπέργειο τμήμα του φυτού. Μετά από αυτό το στάδιο η προστασία της καλλιέργειας ολοκληρώνεται με τον ψεκασμό του εδάφους με DNOC (δινιτροορθοκρεζόλη).

Παραπομπές

Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales (previously known as Uredinales).

An estimated 168 rust genera and approximately 7,000 species, more than half of which belong to the genus Puccinia, are currently accepted.^[2] Rust fungi are highly specialized plant pathogens with several unique features. Taken as a group, rust fungi are diverse and affect many kinds of plants. However, each species has a very narrow range of hosts and cannot be transmitted to non-host plants. In addition, most rust fungi cannot be grown easily in pure culture.

A single species of rust fungi may be able to infect two different plant hosts in different stages of its life cycle, and may produce up to five morphologically and cytologically distinct spore-producing structures viz., spermogonia, aecia, uredinia, telia, and basidia in successive stages of reproduction.^[3] Each spore type is very host specific, and can typically infect only one kind of plant.

Rust fungi are obligate plant pathogens that only infect living plants. Infections begin when a spore lands on the plant surface, germinates, and invades its host. Infection is limited to plant parts such as leaves, petioles, tender shoots, stem, fruits, etc.^[2] Plants with severe rust infection may appear stunted, chlorotic (yellowed), or may display signs of infection such as rust fruiting bodies. Rust fungi grow intracellularly, and make spore-producing fruiting bodies within or, more often, on the surfaces of affected plant parts.^[2] Some rust species form perennial systemic infections that may cause plant deformities such as growth retardation, witch's broom, stem canker, galls, or hypertrophy of affected plant parts.

Rusts get their name because they are most commonly observed as deposits of powdery rust-coloured or brown spores on plant surfaces. The Roman agricultural festival Robigalia (April 25) has ancient origins in combating wheat rust.^[4]

Impacts

Rusts are considered among the most harmful pathogens to agriculture, horticulture and forestry. Rust fungi are major concerns and limiting factors for successful cultivation of agricultural and forest crops. White pine blister rust, wheat stem rust, soybean rust, and coffee rust are examples of notoriously damaging threats to economically important crops.^[2] Climate change can have a possible impact to increase rust fungi by increase in CO₂ and O₃, climate warming, humidity, extreme weather changes.^[5]

Life cycle

All rusts are obligate parasites, meaning that they require a living host to complete their life cycle. They generally do not kill the host plant but can severely reduce growth and yield.^[6] Cereal crops can be devastated in one season; oak trees infected in the main stem within their first five years by the rust Cronartium quercuum often die.^[7]

Rust fungi can produce up to five spore types from corresponding fruiting body types during their life cycle, depending on the species. Roman numerals have traditionally been used to refer to these morphological types.

• 0-Pycniospores (Spermatia) from Pycnidia. These serve mainly as haploid gametes in heterothallic rusts.
• I-Aeciospores from Aecia. These serve mainly as non-repeating, dikaryotic, asexual spores, and go on to infect the primary host.
• II-Urediniospores from Uredia (Uredinia). These serve as repeating dikaryotic vegetative spores. These spores are referred to as the repeating stage because they can cause auto-infection on the primary host, re-infecting the same host on which the spores were produced. They are often profuse, red/orange, and a prominent sign of rust disease.
• III-Teliospores from Telia. These dikaryotic spores are often the survival/overwintering stage of the life cycle. They usually do not infect a plant directly; instead they germinate to produce basidia and basidiospores.
• IV-Basidiospores from Teliospores. These windborne haploid spores often infect the alternate host in Spring.^[8][9] They are rarely observed outside of the laboratory.

Rust fungi are often categorized by their life cycle. Three basic types of life cycles are recognized based on the number of spore types as macrocyclic, demicyclic, and microcyclic.^[2] The macrocyclic life cycle has all spore states, the demicyclic lacks the uredinial state, and the microcyclic cycle lacks the basidial, pycnial, and the aecial states, thus possess only uredinia and telia. Spermagonia may be absent from each type but especially the microcyclic life cycle. In macrocyclic and demicyclic life cycles, the rust may be either host alternating (heteroecious) (i.e., the aecial state is on one kind of plant but the telial state on a different and unrelated plant), or non-host alternating (autoecious) (i.e., the aecial and telial states on the same plant host).^[2] Heteroecious rust fungi require two unrelated hosts to complete their life cycle, with the primary host being infected by aeciospores and the alternate host being infected by basidiospores. This can be contrasted with an autoecious fungus, such as Puccinia porri, which can complete all parts of its life cycle on a single host species.^[8] Understanding the life cycles of rust fungi allows for proper disease management.^[10]

Host plant-rust fungus relationship

There are definite patterns of relationship with host plant groups and the rust fungi that parasitize them. Some genera of rust fungi, especially Puccinia and Uromyces, comprise species that are capable of parasitizing plants of many families. Other rust genera appear to be restricted to certain plant groups. Host restriction may, in heteroecious species, apply to both phases of life cycle or to only one phase.^[2] As with many pathogen/host pairs, rusts are often in gene-for-gene relationships with their plants. This rust-plant gene-for-gene interaction differs somewhat from other gene-for-gene situations and has its own quirks and agronomic significance. Rust fungi decrease photosynthesis and elicit the emissions of different stress volatiles with increasing severity of infection.^[11]

Infection process

The spores of rust fungi may be dispersed by wind, water or insect vectors.^[12] When a spore encounters a susceptible plant, it can germinate and infect plant tissues. A rust spores typically germinates on a plant surface, growing a short hypha called a germ tube. This germ tube may locate a stoma by a touch responsive process known as thigmotropism. This involves orienting to ridges created by epidermal cells on the leaf surface, and growing directionally until it encounters a stoma.^[13]

Over the stoma, a hyphal tip produces an infection structure called an appressorium. From the underside of an appressorium, a slender hypha grows downward to infect plant cells^[14] It is thought that the whole process is mediated by stretch-sensitive calcium ion channels located in the tip of the hypha, which produce electric currents and alter gene expression, inducing appressorium formation.^[15]

Once the fungus has invaded the plant, it grows into plant mesophyll cells, producing specialized hyphae known as haustoria. The haustoria penetrate cell walls but not cell membrances: plant cell membranes invaginate around the main haustorial body forming a space known as the extra-haustorial matrix. An iron and phosphorus rich neck band bridges the plant and fungal membranes in the space between the cells for water flow, known as the apoplast, thus preventing the nutrients reaching the plant's cells. The haustorium contains amino acid and hexose sugar transporters and H⁺-ATPases which are used for active transport of nutrients from the plant, nourishing the fungus.^[16] The fungus continues growing, penetrating more and more plant cells, until spore growth occurs. The process repeats every 10 – 14 days, producing numerous spores that can be spread to other parts of the same plant, or to new hosts.

Common rust fungi in agriculture

^[8][10][17]

• Cronartium ribicola (White pine blister rust); the primary hosts are currants, and white pines the secondary. Heterocyclic and macrocyclic
• Gymnosporangium juniperi-virginianae (Cedar-apple rust); Juniperus virginiana is the primary (telial) host and apple, pear or hawthorn is the secondary (aecial) host. Heteroecious and demicyclic
• Hemileia vastatrix (Coffee rust); Primary host is coffee plant; unknown alternate host. Heteroecious
• Phakopsora meibomiae and P. pachyrhizi (Soybean rust); Primary host is soybean and various legumes. Unknown alternate host. Heteroecious
• Puccinia coronata (Crown Rust of Oats and Ryegrass); Oats are the primary host; Rhamnus spp. (Buckthorn) is alternate host. Heteroecious and macrocyclic
• Puccinia graminis (Stem rust of wheat and Kentucky bluegrass, or black rust of cereals); Primary hosts include: Kentucky bluegrass, barley, and wheat; Common barberry is the alternate host. Heteroecious and macrocyclic
• Puccinia hemerocallidis (Daylily rust); Daylily is primary host; Patrinia sp is alternate host. Heteroecious and macrocyclic
• Puccinia kuehnii (Orange rust of Sugarcane)
• Puccinia melanocephala (Brown Rust of Sugarcane)
• Puccinia porri (Leek rust); Autoecious
• Puccinia sorghi (Common Rust of Corn)^[18]
• Puccinia striiformis (Yellow Rust) of cereals
• Puccinia triticina (Brown Wheat Rust) in grains
• Uromyces appendiculatus (Bean Rust) in common bean (Phaseolus vulgaris)^[19]

Management of rust fungi diseases

Research

Efforts to control rusts began to be scientifically based in the 20th century.^[20] Elvin C. Stakman initiated the scientific study of host resistance, which had heretofore been poorly understood and handled by individual growers as part of the breeding process.^[20] Stakman was followed by H. H. Flor's extensive discoveries of rust genetics.^[20] In order to study rust metabolics, Tervet et al., 1951 developed the cyclone separator.^[20] The cyclone separator allows the mechanised collection of spores for study – Cherry & Peet 1966's improved version gathers even more efficiently.^[20] (Cherry & Peet 1966 also resulted in the US government's abandonment of all biological weapons programs using rust fungi.)^[20] This device was first put to work testing the composition of the spores themselves, especially substances coating the outside of the spores which signal population density.^[20] When detected they help prevent crowding.^[20]

Control

The control methods of rust fungus diseases depend largely on the life cycle of the particular pathogen. The following are examples of disease management plans used to control macrocyclic and demicyclic diseases:

Macrocyclic Disease: Developing a management plan for this type of disease depends largely on whether the repeating stage (urediniospores) occur on the economically important host plant or the alternate host. For example, the repeating stage in white pine blister rust disease does not occur on white pines but on the alternate host, Ribes spp. During August and September Ribes spp. give rise to teliospores which infect white pines. Removal of the alternate host disrupts the life cycle of the rust fungi Cronartium ribicola, preventing the formation of basidiospores which infect the primary host. Although spores from white pines cannot infect other white pines, survival spores may overwinter on infected pines and reinfect Ribes spp. the following season. Infected tissue is removed from white pines and strict quarantines of Ribes spp. are maintained in high risk areas.^[8][21]

Puccinia graminis is a macrocyclic heteroecious fungus that causes wheat stem rust disease. The repeating stage in this fungus occurs on wheat and not the alternate host, barberry. The repeating stage allows the disease to persist in wheat even though the alternate host may be removed. Planting resistant crops is the ideal form of disease prevention, however, mutations can give rise to new strains of fungi that can overcome plant resistance. Although the disease cannot be stopped by removal of the alternate host, the life cycle is disrupted and the rate of mutation is decreased because of reduced genetic recombination. This allows resistance bred crops to remain effective for a longer period of time.^[8][22]

Demicyclic Disease: Because there is no repeating stage in the life cycle of demicyclic fungi, removal of the primary or the alternate host will disrupt the disease cycle. This method, however, is not highly effective in managing all demicyclic diseases. Cedar-apple rust disease, for example, can persist despite removal of one of the hosts since spores can be disseminated from long distances. The severity of Cedar-apple rust disease can be managed by removal of basidiospore producing galls from junipers or the application of protective fungicides to junipers.^[23]

Home control

Rust diseases are very hard to treat. Fungicides such as Mancozeb or Triforine may help but may never eradicate the disease. Some organic preventative solutions are available and sulphur powder is known to stop spore germination. High standards of hygiene, good soil drainage, and careful watering may minimize problems. Any appearance of rust must be immediately dealt with by removing and burning all affected leaves. Composting, or leaving infected vegetation on the ground will spread the disease.

Commercial control

In some large acreage crops, fungicides are applied by air. The process is expensive and fungicide application is best reserved for seasons when foliar diseases are severe. Research indicates, the higher the foliar disease severity, the greater the return from the use of fungicides.^[24] Southern corn rust disease, can be confused with common rust. Southern rust's distinguishing characteristic is that pustules form mostly on the upper leaf surface and spores are more orange in color. Southern rust spreads more quickly and has a higher economic impact when hot, humid weather conditions persist. Timely fungicide applications to control southern rust are more crucial than with common rust.^[25]

A variety of preventative methods can be employed for rust diseases:

• High moisture levels may exacerbate rust disease symptoms. The avoidance of overhead watering at night, using drip irrigation, reducing crop density, and using fans to circulate air flow may decrease disease severity.
• The use of rust resistant plant varieties
• Crop rotation can break the disease cycle because many rusts are host specific and do not persist long without their host.
• Inspection of imported plants and cuttings for symptoms. It is important to continuously observe the plants because rust diseases have a latent period (plant has the disease but shows no symptoms).
• Use of disease-free seed can reduce incidence for some rusts^[22]

Host plants affected

It is probable that most plant species are affected by some species of rust. Rusts are often named after a host species that they infect. For example; Puccinia xanthii infects the flowering plant cocklebur (Xanthium). Recently, a total of 95 rust fungi belonging to 25 genera associated with 117 forest plant species belonging to 80 host genera under 43 host families were reported from the Western Ghats, Kerala, India.^[2] Rust fungi include:

Rust infected host genera include:^[2]

Some of the better known hosts include:

Hyperparasites of rusts

In the family Sphaeropsidaceae of Sphaeropsidales fungi, species of the genus Darluca are hyperparasites on rusts.^[26]

Gallery

• 

  Rust fungus on a leaf, under low magnification.

• 

  Urediniospores of a rust fungus.

• 

  Diagram representing the infection process of rust fungi

• 

  Rust fungus, Puccinia urticata on the surface of a nettle leaf

• 

  Rust on onions

See also

• Stem rust
• Wheat leaf rust
• Leaf rust (barley)
• Fungus
• Smut (fungus)
• Soybean rust
• Rust (programming language) (named after the Rust fungus^[27])

References

Retrieved from "https://en.wikipedia.org/w/index.php?title=Rust_(fungus)&oldid=1154513155"

Rustofungoj (Pucciniales) apartenas al la bazidiomicetoj (Basidiomycetes), kiuj malsanigas pli ol 4000 utilplantojn kaj fiherbojn. Dum siaj vivcikloj, ili parazitas sur unu aŭ du mastroplantoj.

Kelkaj el la duplantaj specioj:

• nigra rustofungo (sur tritiko kaj aliaj graminacoj) (Puccinia graminis); alia mastroplanto estas la berberiso (Berberis).
• riba rustofungo (Cronartium ribicola) parazitas Ribes-speciojn (ribo, groso) kaj aliflanke kvinpinglajn pinojn kiel longvivan pinon.

La unuplantaj specioj de rustofungo parazitas asparagon, fazeolon, krizantemon, kafon, rozalteon, antirinon kaj sukerbeton.

La rustofungo aperas kiel makulo plej ofte flava, oranĝ-flava, ruĝa, rust-ruĝa, brua aŭ nigra. Ĝi aperas sur folioj, junaj ŝosoj kaj fruktoj kaj kaŭzas malpliiĝon de la kreskemo kaj produktemo.

Protekto okazas per kultivado de rezistaj kulturvarioj, izolado de la infektitaj agroj, detruado de la mastroplantoj, fungicidoj (du semajnojn antaŭ atendebla apero de la fungo, kaj ripetante je ĉiuj 7–10 tagoj.

Rustosimilan malsaniĝon kaŭzas ankaŭ specioj de blanka dartro (Albugo-genro el Peronosporales). Ili estas unuplantaj fungoj, ne bezonas pluan mastroplanton. Ĝi atakas unujarajn plantojn, kaŭzante helflavajn makulojn sur folioj, blankan koloriĝon sur aliaj plantoj. Tiuj lastaj iĝas vaksaj, poste sekiĝas kaj nigriĝas. La folioj ofte velkas, formortas, kresko haltas. La protektado samas kiel supre.

Pucciniales es un orden de hongos de la división Basidiomycota de la clase Pucciniomycetes conocidos como royas, argeñas, herrumbre o sarro.^[1]​

Los pucciniales son patógenos importantes de plantas y pueden parasitar a cualquier tipo de planta. Las royas se consideran entre los patógenos más dañinos para la agricultura, la horticultura y la silvicultura. Generalmente no matan a la planta huésped, pero pueden reducir severamente el crecimiento y el rendimiento.^[2]​

Se estima que actualmente hay alrededor de 168 géneros y aproximadamente 7,000 especies, más de la mitad pertenecen al género Puccinia.^[2]​

Familias

Contiene las siguientes familias:^[3]​

• Chaconiaceae
• Coleosporiaceae
• Cronartiaceae
• Melampsoraceae
• Mikronegeriaceae
• Phakopsoraceae
• Phragmidiaceae
• Pileolariaceae
• Pucciniaceae
• Pucciniosiraceae
• Pucciniastraceae
• Raveneliaceae
• Sphaerophragmiaceae
• Uncolaceae
• Uropyxidaceae

Referencias

Herdoila, gorrina edo ugerra onddoen Pucciniales ordenako espezieek sortutako gaixotasuna da. Lehen Uredinales zen ordena horren izena. Puccinia da onddoen talde horretako genero ezagunena. Belaunaldi-txandaketa berezi bat burutzen dute uda-esporen eta negu-esporen artean.

Herdoilak hainbat landare-espezie erasaten ditu, eta Euskal Herriko baratzeetan oso ezaguna da baratxuria eta porrua bezalako espeziak erasotzen dituelako ia urtero. Hostoak, zurtoinak, fruituak zein haziak erasan ditzake.

Eguraldi hezea dagoenean errazago agertzen da. Kolore horia, laranja edo arrea duen hauts itxura du, oilaur txikitxoz osaturikoa, eta hosto edo beste edozein azaleraren azpialdeetan garatzen da.

Familiak

• Chaconiaceae
• Coleosporiaceae
• Cronartiaceae
• Melampsoraceae
• Micronegeriaceae
• Phakopsoraceae
• Phragmidiaceae
• Pileolariaceae
• Pucciniaceae
• Pucciniastraceae
• Raveneliaceae
• Sphaerophragmiaceae
• Uncolaceae
• Uropyxidaceae

Kanpo estekak

Ruostesienet (Pucciniales vanh. Uredinales) ovat kasveissa loisina eläviä sienilajeja. Ne eivät koskaan muodosta itiöemiä, sillä sieni muodostaa helmi-itiöpesäkkeitä.^[2]. Niiden rihmasto kasvaa isäntäkasvin solukkojen soluväleissä. Ne eivät yleensä tapa isäntäänsä. Ruostesieniin kuuluu viljelyskasvien tuholaisia.^[3]

Ruostesienet ovat kehittyneet jo ennen kivihiilikautta.^{helmi-itiöitä, jotka tarttuvat talvikkeihin. Sieni talvehtii talvikin lehdissä ja kasvattaa talvi-itiöitä, jotka taas tarttuvat kuusen emikukintoihin touko-kesäkuussa.[4]}

Kuusessa tuhoa aiheuttaa kuusentuomiruoste (Thekopsora areolata). Laji loisii tuomella ja kuusella, ja sitä voi torjua hävittämällä edellä mainitut kuusikoista.^[5] Muita kuusta tuhoava ruostesieniä ovat kuusentalvikkiruoste (Chrysomyxa pirolata), kuusensuopursuruoste (Chrysomyxa ledi) ja kuusenneulasruoste (Chrysomyxa abietis).^[6] Katajaa ja pihlajaa väli-isäntänään käyttää katajanpihlajaruoste (Gymnosporangium cornutum).^[7]

Eräät ruostesienet vaurioittavat viljoja, kuten esimerkiksi heinäkasveilla ja happomarjapensailla vuorotteleva mustaruoste (Puccinia graminis)^[8][3], sekä erityisesti vehnää vaurioittava keltaruoste (Puccinia striiformis).^[9] Sienet häiritsevät viljan kasvua käyttämällä kasvin vettä ja ravinteita^[10]. Tällöin kasvi ei kasva kunnolla, vaan jää pieneksi ja ohueksi, jolloin viljasadon määrä pienenee ja laatu heikkenee. Viljasadon pienentyminen aiheuttaa materiaalin menetystä viljateollisuudelle, sekä rahallista menetystä viljelijöille. Puccinia -suvun viljaruostesieniä tavataan ympäri maailmaa kaikkialla, missä viljaa kasvaa, sillä sienet levittäytyvät laajalle alueelle hyvin tehokkaasti tuulen kuljettaessa sienten itiöitä ^[10]. Paras tapa ehkäistä ruostesienten aiheuttamia haittoja on viljellä ruostesienille vastustuskykyisiä viljalajikkeita^[10].

Lähteet

Aiheesta muualla

• Suomen hävinneet, uhanalaiset ja silmälläpidettävät ruostesienet Ympäristökeskus (Archive.is)
• Tree of Life web

Les Pucciniales (anciennement Uredinales) sont un ordre de champignons basidiomycètes de la classe des Pucciniomycetes.

Les espèces de l'ordre des Pucciniales sont toutes des parasites obligatoires, pathogènes des plantes vasculaires, responsables de la plupart des maladies appelées « rouilles ». On dénombre environ 7000 espèces réparties en 150 genres et 13 familles^[1].

Liste des familles

Selon Catalogue of Life (3 novembre 2014)^[2] :

Selon ITIS (3 novembre 2014)^[3] :

Notes et références

Voir aussi

Fungas seadánach a tharlaíonn mar líonra snáithíneach idir cealla an phlanda óstaigh. Thar 4,000 speiceas ann, cuid acu seadánach ar ghránbharra tráchtálacha.

Tá an t-alt seo bunaithe ar ábhar as Fréamh an Eolais, ciclipéid eolaíochta agus teicneolaíochta leis an Ollamh Matthew Hussey, foilsithe ag Coiscéim sa bhliain 2011. Tá comhluadar na Vicipéide go mór faoi chomaoin acu beirt as ucht cead a thabhairt an t-ábhar ón leabhar a roinnt linn go léir. Is síol é an t-alt seo. Cuir leis, chun cuidiú leis an Vicipéid.
Má tá alt níos forbartha le fáil i dteanga eile, is féidir leat aistriúchán Gaeilge a dhéanamh.

Penyakit karat adalah segolongan penyakit tumbuhan yang disebabkan oleh golongan cendawan (fungi) yang termasuk dalam bangsa (ordo) Pucciniales.

Penyakit ini paling jelas gejalanya terlihat pada daun, sehingga disebut karat daun. Gejala dicirikan oleh munculnya bercak berwarna coklat kemerahan pada daun yang semakin lama semakin membesar. Bercak ini biasanya dikelilingi oleh jaringan berwarna kuning akibat daun mengalami klorosis. Selain daun, dampak dan gejala penyakit ini dapat tampak pula di buah, batang, pucuk, serta beberapa jaringa lain yang berklorofil. Penyakit karat juga menyebabkan deformasi, perubahan bentuk organ tanaman.

Contoh penyakit karat:

• karat daun kopi, disebabkan cendawan Hemileia vastatrix
• karat jagung, disebabkan beberapa jenis Puccinia
• karat padi
• karat gandum

Artikel bertopik biologi ini adalah sebuah rintisan. Anda dapat membantu Wikipedia dengan mengembangkannya.

Gli Uredinales o Uredinali sono un ordine di funghi Basidiomiceti. Sono funghi microscopici più conosciuti con il nome comune di ruggini.

Ciclo vitale

Fase spermogonica

Il ciclo vitale delle Uredinales è alquanto complesso: dalle teleutospore, che si formano nei teleutosori, in primavera, germinano i basidi da cui prendono forma le basidiospore. Queste sviluppano un micelio primario, il quale attraversa l'epidermide dell'ospite, determinando sulle sue foglie superiormente dei punti neri (detti spermogoni) ed in corrispondenza della pagina inferiore pustole gialle dette ecidi. Gli spermogoni, corpiccioli in forma di fiasco, contengono piccoli spermazi unisessuali, portati da esili filamenti e frammisti ad ife ricettive, anch'esse unisessuali.

Fase ecidiosporica

Grazie agli insetti che passano da uno spermogonio all'altro, spermazi di un sesso vengono a contatto con ife ricettive del sesso opposto, i loro nuclei attraverso gli organi ricettivi possono raggiungere gli ecidi che divengono binucleati e danno origine alle ecidiospore, le quali germinano un micelio binucleato che penetra nei tessuti dell'ospite determinando a sua volta delle pustole lineari, gli uredosori, costituiti dalle uredospore, con le quali il ciclo si chiude.

Considerazioni finali

Non sempre il ciclo vitale delle ruggini è così completo: molte mancano di alcune forme di fruttificazione oppure di esse non si conosce ancora qualche forma, specie quella teleutosporica, più difficile da individuare. Fatto comune è invece un'alternanza di ospite per cui la forma spermogonico-ecidiosporica si attua su un ospite e quella uredo-teleutosporica su un altro ospite e sono le basidiospore e le ecidiospore quelle che producono l'infezione su piante diverse da quelle in cui si sviluppano.

Robigo est morbus virentium ac in primis frumenti, cuius causa est fungus parasitus ex ordine Puccinialium, qui ordo etiam Uredinalium dictus est quod plantas "urebant". Partes aegrae colore rubicundo adficiuntur, robiginosi ferri simili, unde nomen huius morbi.

Apud antiquos Romanos etiam dea Robigo fuit (nisi nonnumquam deus erat Robigus nomine) quae agricolis placanda erat ne segetibus noceret : nam frumenta vastabat.

Haec pagina est stipula. Amplifica, si potes!

Rūsas sēnes (Pucciniales, agrāk Uredinales) ir bazīdijsēņu nodalījuma rinda — mikroskopiskas patogēnas sēnes, kas izraisa augu slimības — rūsu. Rūsas sēnes ir obligāti parazīti, biotrofi organismi, kas attīstās uz noteikta saimniekauga dzīvajām šūnām, izraisot tā saslimšanu un nodarot būtisku kaitējumu populācijai vai sējumiem. Sēne veido brūnas, oranžas vai dzeltenas pustulas (spilventiņi) uz lapu vai augu virsmas, kas atgādina dzelzs rūsu un kļuva par iemeslu Pucciniales kārtas nosaukumam. Pustulu krāsa, izvietojums un lielums ir atkarīgs no sēnes sugas.

Rūsas ir fenotipiski un ģenētiski plastiski organismi ar sarežģītu dzīves ciklu.^[1] Attīstības ciklā secīgi mainās haploīdās un diploīdās kodola fāzes. Sēnes agresivitāte raksturojas ar liela sporu daudzuma producēšanu, kas izplatās ar vēju lielos attālumos, un ar ģenētisko mainību, jo rodas jaunas agresīvas sēņu rases, kas var inficēt rezistentās augu šķirnes.^[2]

Rūsas sēnes izraisa lauksaimnieciski nozīmīgas augu slimības. Slimajiem augiem pastiprinās transpirācija un pazeminās fotosintēzes intensitāte, lapas pāragri nokalst. Vidēji stipras infekcijas gadījumā ražas zudumi var sasniegt 15-30%. Jo agrākās auga attīstības fāzēs notiek inficēšanās, jo lielāki ir ražas zudumi.^[3]

Attīstības cikls

Attīstības cikls rūsas sēnēm ir sarežģīts, iedalāms trīs stadijās – pavasara, vasaras un ziemas. Ir pieci dažādi sporu tipi:

• 0 — spermogoniji ar spermācijiem;
• I — ecīdijas ar ecīdijsporām;
• II — uredīniji ar uredosporām;
• III — telīdiji ar telīdijsporām;
• IV — bazīdiji ar bazīdijsporām.

Makrocikliskas rūsas sēnes veido visas piecas sporas. Mikrocikliskas neveido spermācijus, ecīdijsporas un bazīdijsporas, bet demicikliskas — neveido uredosporas. Rūsas attīstības cikla izprašanai ir svarīga nozīme slimības ierobežošanā.

Makrocikliskām un demicikliskām rūsas sēnēm var būt nepieciešami divi dažādi samniekaugi, lai pabeigtu dzīves ciklu. Piemēram svītru rūsa Puccinia graminis parazitē uz graudaugiem, bet kā starpsaimnieks ecīdiju formai tiek izmantotas bārbeles.

Inficēšanās

Rūsas sēņu producētās bezdzimumsporas izplatās ar vēju, ūdeni vai kukaiņiem. Inficēšanās notiek, uz auga nonākot bazīdijsporām, kas no sēņu bazīdijām izplatās galvenokārt ar vēju. Lai notiktu inficēšanās, sporām jānonāk uz dzīvām auga šūnām. Inficētās auga daļas vai augus ieteicams iznīcināt, jo slimība optimālos apstākļos strauji izplatās.

Ierobežošana

1. Fungicīdu pielietošana
2. Rezistentu šķirņu izvēle
3. Augu maiņa var apturēt sēnes dzīves ciklu, ja patogēns ir sugas specifisks
4. Regulāra augu apsekošana, lai noteiktu slimību tās attīstības sākumā (īpaši pēc lietus un augsta mitruma laikā)
5. Veselu, neinficētu sēklu izvēle

Graudaugu rūsas

Graudaugu rūsas ierosina Puccinia spp. sēnes. Ierosinātāji ir obligāti parazīti ar šauru specializāciju. Patogēna izplatība un attīstība ar atkarīga no šķirnes izturības. Kviešu rūsa ir vissenāk pazīstamā augu slimība

Latvijā sastopamas sešu veidu graudaugu rūsas:

• Puccinia striiformis – graudzāļu dzeltenā rūsa
• Puccinia graminis – graudzāļu stiebru (svītru) rūsa
• Puccinia tritici – kviešu lapu brūnā rūsa
• Puccinia hordei – miežu pundurrūsa
• Puccinia dispersa (recondita) – rudzu lapu brūnā rūsa
• Puccinia coronata – auzu vainagrūsa

Citi izplatīti rūsas ierosinātāji ^[4]

• Gymnosporangium fuscum - bumbieru-kadiķu rūsa
• Gymnosporangium juniperinum - ābeļu-kadiķu rūsa
• Gymnosporangium juniperi-virginianae - ābeļu Amerikas rūsa
• Melampsoridium betulinum - bērzu rūsa
• Phragmidium rubi-idaei - aveņu rūsa
• Puccinia porri - puravu rūsa
• Tranzschelia pruni-spinosae - plūmju rūsa
• Uromyces pisi - zirņu rūsa
• Uromyces trifolii-repentis - baltā āboliņa rūsa
• Uromyces viciae-fabae – pupu rūsa

Atsauces

Schimmels

De Uredinales (Pucciniales) vormen een orde van schimmels (Fungi) uit de klasse van roesten (Urediniomycetes, Pucciniomycetes)).

Uredinales leven als parasiet op vaatplanten. Veel soorten hebben twee soorten gastplanten nodig om hun levenscyclus te voltooien. De Uredinales behoren tot de meest gevreesde schimmels in de landbouw vanwege hun schade die ze kunnen veroorzaken bij gewassen. Er zijn ongeveer 4600 soorten.

Taxonomie

De indeling van de Uredinales is als volgt:

Orde: Uredinales

• Familie: Chaconiaceae
• Familie: Coleosporiaceae
• Familie: Cronartiaceae
• Familie: Melampsoraceae
• Familie: Micronegeriaceae
• Familie: Phakopsoraceae
• Familie: Phragmidiaceae
• Familie: Pileolariaceae
• Familie: Pucciniaceae
• Familie: Pucciniastraceae
• Familie: Pucciniosiraceae
• Familie: Raveneliaceae
• Familie: Sphaerophragmiaceae
• Familie: Uncolaceae
• Familie: Uropyxidaceae

Rustsoppordenen (Pucciniales) er ein orden av parasittiske stilksporesoppar.^[1][2]

Kjelder

1. ↑ Artsdatabanken
2. ↑ «rustsopper» i Store norske leksikon, snl.no. Henta 18. august 2019.

Rdzowce (Pucciniales Clem. & Shear) – rząd grzybów należący do klasy rdzy (Pucciniomycetes)^[1].

Cykle życiowe

Cykl życiowy rdzowców może przebiegać na jednym żywicielu (pasożyty jednodomowe), lub na dwóch gatunkach żywicieli (pasożyty dwudomowe). Mogą wytwarzać następujące rodzaje zarodników: bezpłciowe spermacja (oznaczane jako 0), ecjospory (I), urediniospory (II), teliospory (III), oraz płciowe bazydiospory (IV). Niektóre gatunki wytwarzają wszystkie rodzaje zarodników (rdze pełnocykliczne), u niektórych cykl życiowy jest uproszczony, brak niektórych rodzajów zarodników (rdze niepełnocykliczne). W zależności od tych dwóch cech Cummins i Hiratsuka wyróżnili następujące typy cyklów życiowych rdzowców^[2]:

• heteromakrocykliczny – rdzowce dwudomowe i pełnocyklowe (0, I. II, III, IV), jak np. u Puccinia graminis,
• automakrocykliczny – rdzowce jednodomowe i pełnocyklowe, jak np. u Phragmidium mucronatum,
• heterodemicykliczne – rdzowce dwudomowe i niepełnocyklowe (0, I-III), jak np. u Gymnosporangium,
• autodemicykliczne – rdzowce iednodomowe i niepełnocyklowe (0, I, III), jak np. u Uromyces minor,
• mikrocykliczne – rdzowce jednodomowe, tworzące tylko teliospory (III), jak np. u Puccinia malvacearum,
• endocykliczne – rdzowce jednodomowe, tworzące spermacja i ecjospory (0, I), które pełnią rolę teliospor, jak np. u Endophyllum sempervivi^[2].

Systematyka

Pozycja w klasyfikacji według Index Fungorum

Pucciniales, Incertae sedis, Pucciniomycetes, Pucciniomycotina, Basidiomycota, Fungi^[1].

Rodzaje

Według aktualizowanej klasyfikacji Index Fungorum bazującej na Dictionary of the Fungi do rzędu Pucciniales należą następujące rodziny oraz rodzaje incertae sedis^[3]:

• Chaconiaceae Cummins & Y. Hirats. 1983
• Coleosporiaceae Dietel 1900 – pęcherzycowate
• Cronartiaceae Dietel 1900 –
• Melampsoraceae Dietel 1897 – melampsorowate
• Mikronegeriaceae Cummins & Y. Hirats. 1983
• Phakopsoraceae Cummins & Hirats. f. 1983
• Phragmidiaceae Corda 1837
• Pileolariaceae Cummins & Y. Hirats. 1983
• Pucciniaceae Chevall. 1826 – rdzowate
• Pucciniastraceae Gäum. ex Leppik 1972 – rdzakowate
• Pucciniosiraceae Cummins & Y. Hirats. 1983
• Raveneliaceae Leppik 1972,
• Uncolaceae Buriticá 2000
• Uropyxidaceae Cummins & Y. Hirats. 1983
• rodzaje incertae sedis: Aecidiconium, Aecidiolum, Aecidium, Caeoma, Caeteas, Cerradoa, Coleopuccinia, Desmella, Desmellopsis, Desmosorus, Edythea, Elateraecium, Erysibe, Flaminia, Hemileia, Hennenia, Hiratsukaia, Hiratsukamyces, Intrapes, Malupa, Masseeëlla, Mehtamyces, Peridermium, Pelastoma, Phragmotelium, Puccorchidium, Schroeteriaster, Sphenorchidium, Uraecium, Uredo.

Przypisy

Pucciniales é uma ordem de fungos vulgarmente designados ferrugens. Muitas destas espécies são parasitas de plantas. Alguns são superficialmente semelhantes aos carvões, apesar da relação entre os dois grupos não ser clara. A taxonomia de Pucciniomycotina (antigamente Urediniomycetes), como um todo, encontra-se em mudança contínua.

Muitas ferrugens têm dois ou mais hospedeiros (são heteróicas) e até cinco estágios de esporo. Contudo, normalmente reproduzem-se por meio de produção de esporos assexuados. Os esporos são levados pelo ar podendo viajar grandes distâncias. Infectam sobretudo as folhas dos hospedeiros.

O nome comum deste grupo de fungos deve-se ao facto de algumas espécies terem um estágio de esporo de cor avermelhada, o qual se assemelha ao processo de corrosão conhecido como ferrugem.

Uma ferrugem economicamente relevante é a ferrugem-do-trigo, Puccinia triticina, uma doença fúngica séria que afecta o trigo e o centeio, causando epidemias graves na América do Norte e do Sul.

Processo de infecção

As ferrugens afectam muitas espécies de plantas, mas na maioria dos casos uma espécie de ferrugem pode infectar apenas uma espécie de planta. Tal facto pode tornar as ferrugens úteis no controlo biológico. O que se segue descreve o processo de infecção dos esporos assexuados. Um imagem resumindo este processo pode ser vista na galeria abaixo.

Fixação do esporo

Quando um conídio de ferrugem cai numa superfície da planta, necessita fixar-se a esta, ou seria simplesmente arrastado para fora dela. Primeiro, formam-se interações hidrofóbicas fracas, entre o esporo e a cutina da superfície celular da planta. Então, sinais desconhecidos provocam a produção de moléculas mucilaginosas hidrofóbicas chamadas adesinas. Estas colarão o esporo à superfície da planta de modo irreversível.^[1] Uma vez fixado, o esporo germinará.

Desenvolvimento do tubo germinal

Os fungos das ferrugens penetram na planta usando a abertura natural do estoma, mas para que isso suceda, o tubo germinal em crescimento tem de a localizar. Os fungos das ferrugens evoluíram de modo a localizarem os estomas de modo mais eficiente por meio do recurso ao tigmotropismo. O tubo germinal cresce de uma forma aleatória até alcançar uma crista entre as células da epiderme. Nesta altura, começa a crescer perpendicularmente à crista, aumentando muito as probabilidades de localizar um estoma.^[2]

Formação do apressório

O estoma é o local onde ocorre a formação do apressório, uma estrutura cuja função é ancorar firmemente o fungo e auxiliar na penetração.^[3] Nos fungos das ferrugens a formação do apressório é controlada por um processo de tigmodiferenciação. Os apressórios são formados quando o tubo germinal detecta cristas com dimensões correspondentes às dimensões dos lábios dos estomas da sua espécie hospedeira.

Foi proposto que este processo é mediado por um canal de ião cálcio mecanossensível localizado na extremidade do tubo germinal. Este canal iónico transduziria o estiramento da membrana celular causado pela pelas mudanças na topografia foliar em fluxos iónicos conduzindo a mudanças na expressão dos genes e formação do apressório.^[4]. Esta teoria é apoiada por experiências que mostram que a aplicação externa de Ca²⁺ no tubo germinal provoca diferenciação.

A partir do apressório uma “cavilha” de infecção cresce en direcção ao interior da planta e entre as células do mesofilo.

O haustório

Os fungos das ferrugens são biotróficos, ou seja, obtêm os seus nutrientes de células vivas. Isto requer uma extensão especializada do fungo na célula vegetal viva a que se dá o nome de haustório. Este desenvolve-se a partir de uma célula-mãe. A mebrana celular da célula vegetal invagina em redor do corpo principal do haustório e o espaço entre as duas membranas passa a designar-se matriz extra-haustórica. Um colar rico em ferro e fósforo faz a ponte entre as membranas vegetal e fúngica e funciona como vedante impedindo a passagem de nutrientes para o apoplasto da planta. O haustório contém transportadores de aminoácidos e hexoses e H⁺-ATPases para o transporte activo de nutrientes a partir da célula da planta.^[5]

O fungo da ferrugem continuará então a crescer e a invadir a planta, até estar pronto para a esporulação.

Galeria

• Fungo de ferrugem numa folha, sob baixa ampliação.

• Pústula de urediniósporos.

• Diagrama representando o processo de infecção dos fungos das ferrugens.

Ver também

• Ferrugem-da-soja
• Ferrugem-do-trigo
• Ferrugem-do-café

Referências

• Este artigo foi inicialmente traduzido, total ou parcialmente, do artigo da Wikipédia em inglês, cujo título é «Rust (fungus)», especificamente .

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Pas, asalak mantarlara bağlı bir bitki hastalığıdır.

Bu mantarlar, bazitli mantarlar büyük grubuna ve pas mantarları alt grubuna girerler. Pas terimi, bir mantarın, yılın değişik zamanlarındaki kabarcıklı ve değişikliğe uğramış yüzeylerinin durumunu (lezyon) belirtir; bunlar mantarların etkin gelişme dönemi olan bahar ve yaz mevsiminde kükürt sarısı ya da turuncu (uredo dönemi) renktedirler. Mantarın kış dönemine girdiği (sonbahar veya kış mevsimi) bu kabarcıklı ve değişikliğe uğraşmış yüzeyler, kızılımsı kahverengi ya da siyah (telöto dönemi) bir renk alırlar. Pas mantarının misalyumu hücreler arasındadır ve hücrelerin içine emeçler gönderir; lezyonların yüzeyinde mantarın spor oluşumları ortaya çıkar, bunlar, uredosporlar, daha sonra da telötosporlardır. İnce çeperli olan uredosporlar hafif ve dayanıksızdırlar; mantarın rüzgarla dağılan biçimi uredosporlardır. Telötosporlar kalın çeperli, uredosporlara göre daha ağır ve daha dayanıklıdırlar, asalağın kalıcı biçimini oluştururlar. Bazen üçüncü bir dönem olan esidi dönemi de görülebilir, mevsimsiz ve çok kısa süren bu dönem, uredo ve telöto dönemlerinden önce gelir. Pas mantarlarının dünyada 3000'den fazla türü vardır; bunlara bütün iklimlerde ve çok değişik koşullarda rastlanabilir; hiçbiri çürükçül yaşam sürdüremez ve yapay ortamda üretilemezler; tümü de tohumlu bitkiler (ya da çiçekli bitkiler) ve eğrelti otları gibi öbür bitkilerde yaşamlarını asalak olarak sürdürürler.

Pas hastalığı çok çeşitli zararlara yol açar. Yaprakların sap ya da uç bölümlerini tutan kabarcıklar, bitkinin gelişmesini engeller ve yaprakların kurumasına neden olurlar; meyveler de şankrlara yol açarlar, dalların dallanmasında bozukluklara neden olurlar. Bazı pas mantarları, bütün gelişmelerini, yani esidi, uredo ve telöto dönemlerini aynı bitki üstünde tamamlarlar; bu tür mantarlara tek konaklı denir. Değişik konaklı olarak adlandırılan öbür mantarlarsa, gelişmelerini birbirlerini izleyen iki çevrimde tamamlarlar; birinci çevrim (esidi) genellikle ilkbaharda görülür ve bir destek türü üstünde gelişir, yaz ya da sonbahar mevsiminde görülen ikinci çevrim ise, (uredo ve ardından telöto) değişik bir tür üzerinde gerçekleşir.Böylece doğada çok sayıda "konak çifti" ortaya çıkarılmıştır. Pas mantarları kışı, telötospor biçiminde geçirirler, bazı durumlardaysa misalyum bitki dokularının içinde canlı olarak yaşamını sürdürür. Pas hastalığı, ekim bitkileri için çok tehlikeli bir hastalıktır, özellikle ılıman ülkelerde tahıllara çok zarar verir. Bu bitki hastalığıyla, kimyasal savaş çoğunkukla kesin bir sonuç verememektedir; ama genetik biliminin gelişmesi sayesinde bu hastalıklara dayanıklı türler elde edilebilmiştir.

Царство: Грибы

Подцарство: Высшие грибы

Отдел: Базидиомицеты

Подотдел: Pucciniomycotina

Класс: Пукциниомицеты

Порядок: Ржавчинные грибы

• 1 Описание
• 2 Таксономия
  • 2.1 Синонимы
  • 2.2 Семейства
• 3 Примечания
• 4 Литература

サビキン目（さびきんもく、PuccinialesまたはUredinales）は担子菌門の目の1つで、サビキン（錆菌、銹菌）と総称される。7000種以上が知られる。

植物に寄生する絶対寄生菌で、赤・黒などに着色したさびのように見える無性胞子（さび胞子）を作ることから、これらによる多くの病害はさび病と呼ばれ、農業・林業において重大な病害を含む。リンゴ・ナシなどに寄生する一部のものは特徴的な病斑から赤星病、また樹木に多数の枝葉を叢生させるものは天狗巣病といった別の名で呼ばれる。ただし卵菌による白さび病など、他の菌によるもので「さび病」と呼ばれるものもある。

複雑な生活環を有し、胞子としては「さび胞子」「担子胞子」のほか、種類によって「精子」「夏胞子」「冬胞子」と呼ばれる胞子を作り、またそれぞれの世代が異なる植物に感染・増殖するもの（異種寄生性）も多い。

外部リンク[編集]

• さび病菌（国立科学博物館）
• さび病菌（筑波大学・山岡博士）

この項目は、菌類に関連した書きかけの項目です。この項目を加筆・訂正などしてくださる協力者を求めています（P:生き物と自然／PJ生物）。 この項目は、植物に関連した書きかけの項目です。この項目を加筆・訂正などしてくださる協力者を求めています（プロジェクト:植物／Portal:植物）。

「https://ja.wikipedia.org/w/index.php?title=サビキン目&oldid=67276751」から取得