植物微生物學(xué)

1、植物微生物學(xué)第四講Unlike chromistan fungi - most have no motile stages so best adapted to landlPhylum Chytridiomycota（壺菌門）壺菌門）exception - do have flagellae - 1 posterior whiplash,lPhylum Zygomycota（接合菌門）接合菌門）most have coenocytic hyphae (ie no septae)lPhylum- Dikaryomycota（雙核菌門）雙核菌門）septate hyphae. Largest an

2、d most important group.By far the largest group of fungi:lover 100,000 sp knownlprobably well over 1,000,000 exist!lmany capable of digesting very complex substances (cellulose, lignin， chitin ) - due to extracellular enzymes（胞外酶）胞外酶）lhyphae （菌絲）菌絲） can penetrate into solid masses e.g wood and decom

3、pose it rapidlylproduce vast numbers of spores so capable of spreading rapidly.（產(chǎn)孢繁殖）產(chǎn)孢繁殖） mostly live in water or soil - decomposerssingle cell or hyphae, 營(yíng)養(yǎng)體為簡(jiǎn)單細(xì)胞或營(yíng)養(yǎng)體為簡(jiǎn)單細(xì)胞或菌絲菌絲sometimes develop rhizoids（根狀體）根狀體）often parasiticlSynchytrium（集壺菌屬）集壺菌屬） causes wart disease of potatoes（馬鈴薯癌腫?。R鈴薯癌腫病）Po

4、tato wart diseaseSynchytrium endobioticum severe effect on yield resistant varieties available - but new virulent strains of fungus arising warts contain sporangia which release zoospores - infect new potatoes - cause rapid cell division = wartlwide, thin-walled multinucleate coenocytic hyphae粗大的薄壁多

5、核無隔菌絲粗大的薄壁多核無隔菌絲llimited ability to digest complex substrateslsexual spore = a thick walled zygosporangium（接合孢子）接合孢子） - germinates by meiosis to form new hyphae.Phylum Zygomycotalclass Zygomycetes 接合菌綱Mucorales毛霉目 腐生 - saprobic (eg bread moulds)lcommon saprophytes - but limited ability to degrade co

6、mplex compounds compared to Dikaryomycota lLife cycle - see Rhizopus stolonifer (Fig 3.5)lclass Trichomycetes 毛菌綱- parasites of arthropods 節(jié)肢動(dòng)物的寄生物Eumycotan FungiLife cycle of Rhizopus stoloniferaMucor - Life CycleSexual stages - teleomorphAsexual stages - anamorphZygospore of Rhizopus (diploid - wi

7、ll go through meiosis)Sporangium in RhizopussporangiophoreSporangium containing many sporangiospores (asexual)孢子囊內(nèi)含許多孢子囊內(nèi)含許多孢囊孢子（無性的）孢囊孢子（無性的）Anamorphs in ZygomyceteslChromistan FungilEumycotan Fungi.1. Chytridiomycota2. Zygomycota3. DikaryomycotaAscomycotinaBasidiomycotinaphylasub-phylaCompared to

8、Zygomycota :-1. have thinner hyphae菌絲細(xì)- thicker walls 壁厚 divided into compartments by 有隔 septae which contain pores.隔板有孔2. This makes them tougher and much more able to thrive in drier situations更耐干旱3. More capable of utilizing complex substances - e.g cellulose., lignin, keratin, chitin.4. Many imp

9、ortant pathogens of plantsl5. Very important in mycorrhizal菌根 associations l6. Many species have developed an association with algae to form lichens地衣. l7. Hyphae can fuse and exchange nuclei and form heterokaryons異核體, particularly dikaryons 二核體- necessary stage to sexual reproduction.Dikaryon = cel

10、ls have 2 haploid nuclei of different origins in a stable state - continued on each cell divisionrestricted dikaryophase (only in special fruiting bodies - ascoma)二核階段不長(zhǎng)（與擔(dān)子菌比）Many cells within the ascoma develop into asci. Nuclear fusion and meiosis occurs to form 4, 8, 16 etc ascospores子囊孢子 inside

11、 each ascus子囊.simple septal pores2-layered cell walls雙層壁no clamp connections無鎖狀結(jié)構(gòu)molecular differences from Basidiomycotina (GC content etc.)many pathogenic fungi 許多是病原菌leg humans (ringworm, athletes foot - attack keratin)如足癬lplants - southern corn blight, powdery mildews玉米小斑病和白粉病rots and moulds of

12、wood and cotton etc木材和棉花霉?fàn)€producers of mycotoxins (eg aflatoxin)產(chǎn)毒素如黃曲霉beneficial decomposers of material in soils 土中的分解者insect and nematode predators and parasites昆蟲和線蟲的捕食者和寄生物useful in food (yeast, cheeses) or antibiotic prep. (penicillin, cyclosporine)用于食品（酵母和奶酪）或生產(chǎn)抗生素important in molecular and c

13、lassical genetics分子和經(jīng)典遺傳學(xué)的模式生物。Taphrina deformans - peach leaf curlClaviceps purpurea - ergot of Ryecaused outbreaks of St Anthonys Fire in Middle Ages. Source of LSDHighly prized edible Morels 子囊菌綱filamentous species絲狀菌 酵母綱 unicellular yeast species單細(xì)胞的菌 - 半知菌“綱” catchall group for species without

14、sexual stageslmost Lichen fungi are Ascomycetesl大多數(shù)地衣真菌是子囊菌綱lAnamorph = asexual stages - mitosis - usually haploidl無性階段，有絲分裂，通常是單倍體lTeleomorph = sexual stages - involves dikaryons, diploidy and meiosisl有性階段，涉及二核階段、二倍體階段和減數(shù)分裂三個(gè)階段Teleomorph begins when hyphae anastomose (= fuse together), become dikar

15、yotic and aggregate into compact masses (ascoma). 有性階段始于菌絲融合時(shí)，變成二核體，聚集成緊密的一團(tuán)。lapothecia - open cupsl子囊盤，開放的杯狀物lperithecia + pseudothecia - narrow opening flasksl子囊殼+假囊殼- 小口燒瓶狀lcleistothecia - closed spheres or flasks.l閉囊殼 - 封閉的瓶狀物或燒瓶狀物4. cleistothecium2. perithecium3. pseudothecium1. ApotheciumLife

16、cycle of typical AscomyceteAscomycetesBasidiomycetesclamp connection every time a hyphal cell dividescrozier only found just before ascus formationbitunicate ascus雙層壁的子囊unitunicate 單層壁inoperculate無孔口unitunicate 單層壁operculate ascus有孔口原囊態(tài)的子囊lIn Ascomycetes, anamorphs and teleomorphs often develop at d

17、ifferent times and places. Each stage is therefore often collected in ignorance of the existence of the otherlNormal classification is based on telomorph stages, but mycologists have had to classify specimens in which they only find anamorph stages.lThus parallel systems of nomenclature have sprung

18、up - we have teleomorph genera and anamorph genera and mycologists try to draw connections between them where possible. lDNA analyses will make this much easier in future.l有性和無性階段在不同時(shí)間和地點(diǎn)發(fā)生，采集到的標(biāo)本或是有性或是無性態(tài)，正常的分類 是根據(jù)有性態(tài)，但有些菌只發(fā)現(xiàn)了無性態(tài)，只好根據(jù)無性態(tài)分類。因而有兩個(gè)并行的命名體系。菌物學(xué)家試圖找到兩者間的聯(lián)系。將來DNA分析技術(shù)將使得更容易。lIn some cases

19、it has been possible to connect the anamorph name with the teleomorph name - but in many others this has not yet been done and may never be possible because the organism may have lost the ability to reproduce sexually. lOf 30,000 known Ascomycetes only 5,000 have been connected to their anamorphs -

20、results often messyleg teleomorph genera, Nectria and Gibberella, both have anamorphs which have been classified in the anamorph genus FusariumlMany anamorphs (85%) have no known teleomorph - are termed Deuteromycetes.l有時(shí)將有性與無性聯(lián)系容易，許多情況下難甚至做不到，因?yàn)橛械木鷨适Я擞行陨车哪芰Α?0 000種已知的子囊菌只有5 000種與無性態(tài)掛上了勾，結(jié)果往往是雜亂的，如

21、有性階段的叢剌殼屬和赤霉屬的無性階段都是鐮霉屬。許多（85%）無性態(tài)已知但不知有性態(tài)，歸到半知菌綱。Recombination during MITOSIS has been observed in many fungi - it may be particularly well developed in Deuteromycetes減數(shù)分裂時(shí)發(fā)生重組已在許多真菌中發(fā)現(xiàn)，但半知菌尤多。兩個(gè)不同核的細(xì)胞偶爾融合成為雙核細(xì)胞，通過核融而成體細(xì)胞二倍體，有絲分裂時(shí)發(fā)生交換而分離或丟失染色體成單倍體。Mitotic crossing-over diploid segregantsMitotic div

22、isionsHaploid myceliumDikaryotic cellsSomatic diploids arise through nuclear fusionChromosome loss = haploidizationThe typical anamorph spore in Ascomycetes = conidia produced outside a specialized hyphal cell. 典型無性孢子是分生孢子，外生于特殊菌絲細(xì)胞。compare with Zygomycetes which produce sporangiospores inside a spo

23、rangium.而接合菌的無性孢子是在孢子囊內(nèi)產(chǎn)生孢囊孢子。conidia = asexual spores produced in vast numbers by mitotic divisions分生孢子是通過有絲分裂大量產(chǎn)生的無性孢子lconidial features分生孢子特征 - conidiophores never enclosed分生孢子梗 生 腔孢綱- conidiophores enclosed in a covering.分生孢子梗被封閉lconidial shape and septation importantl孢子形態(tài)和分隔數(shù)是重要依據(jù)lconidiophore

24、details also usedl分生孢子梗的細(xì)節(jié)也用于分類Coelomycetes have their conidia in a covered structure.Covered either by host cells (acervulus分生孢子盤) or by fungal hyphae in flask shape (pycnidium分生孢子器)acervuluspycnidiumconidiumconidiumConidia of 孢子孢子Aspergillus sp.Conidiophore孢子梗孢子梗lYeasts are fungi which typically f

25、orm unicellular cells which divide by budding i.e not filamentous hyphae lMost are Ascomycetous - many form asci, but there are some yeast-like forms in the Zygomycetes and BasidiomyceteslBudding yeast cells considered to be conidialVery important in ecology and for man (brewing and baking)l酵母菌典型情況下

26、形成單細(xì)胞的菌體，即沒有絲狀菌絲，出芽繁殖。大多數(shù)是子囊菌，許多形成子囊，但在1. Plant pathogens植物病原菌植物病原菌 over half of important crop pathogens are Ascomycetes.作物病原菌一半是子囊菌lHelminthosporium maydis - southern corn blight玉米小斑lCryphonectria - chestnut blight - all but eliminated chestnuts in N. America栗疫病lFusarium sp. - cause many wilt dise

27、ases, produce mycotoxins鐮刀菌，造成萎蔫病，產(chǎn)毒素lBotrytis - several plant diseases - can also produce very expensive sweet wine (ice wine)灰霉菌，引致幾種病害，但也生產(chǎn)昂貴的甜葡萄酒。lClaviceps - ergot fungus - causes madness - LSD sourcel麥角菌，造成人類疾病1. Plant pathogens植物病原菌（續(xù)）植物病原菌（續(xù)）lErysiphe - powdery mildews of plants - haustoria

28、penetrate epidermal cells of host plant 白粉菌-引致植物白粉病-吸器穿透到寄主植物表皮細(xì)胞中l(wèi)Ophiostoma - Dutch Elm disease 荷蘭榆疫病lVenturia - apple scab disease 蘋果瘡痂病lTrichoderma - mycoparasite - use in biological control of plant diseasel木霉菌-真菌寄生物-用于植物病害生物防治2. Food and Health 食品與健康（續(xù)）食品與健康（續(xù)）lPenicillium and Aspergillus - us

29、ed in cheese makingThe enzymes of Penicillium camembertii produce the soft, smooth texture of Camembert and Brie cheeses. Penicillium roquefortii puts that strong flavour in blue cheeses such as Roquefort, Danish Blue, Stilton and Gorgonzola. l青霉菌和曲霉菌青霉菌和曲霉菌-用于奶酪生產(chǎn)。青霉菌的酶產(chǎn)生軟光滑的布里白奶酪用于奶酪生產(chǎn)。青霉菌的酶產(chǎn)生軟光滑的

30、布里白奶酪lAspergillus oryzae used in the Far East to turn soya protein into soy sauce l米曲霉在遠(yuǎn)東用于將大豆蛋白轉(zhuǎn)孌成醬油lMorchella (morels) - highly prized mushroom 高價(jià)的蘑菇lTuber (truffles) even more highly prized and priced ! 塊菌，價(jià)格還要高lTrichophyton and other dermatophytes (keratin- attacking fungi) eg ringworm. athletes

31、 foot, jock itch etc 癬菌-足癬等2. Food and Health（食品與健康）食品與健康）lAspergillus flavus (grows on peanuts and many other substrates,producing a mycotoxin called aflatoxin, which contaminates food and causes liver damage - the most potent carcinogen (cancer-inducing) substance known. l黃曲霉（在花生和其它許多基質(zhì)上生長(zhǎng)，產(chǎn)生稱為黃曲霉

32、的毒素，污染食品、造成肝病-最烈性的致癌劑）l Fusarium graminearum, growing on feed corn, produces another mycotoxin, zearalenone, which is a steroid, and causes oestrogenic syndrome - vaginal and rectal prolapse - in young female pigs. l禾谷鐮刀菌，在飼料玉米上生長(zhǎng)，產(chǎn)生另一種霉菌毒素即玉米烯酮，是一種固醇，造成雌激素綜合癥，母豬直腸下垂lPenicillium italicum - example o

33、f the moulds that spoil food in storage .意大利青霉-儲(chǔ)藏的食物變質(zhì)l3. Rots and decomposition 腐爛與分解腐爛與分解lCellulolytic hyphomycetes cause blue stain and soft rot of wood, discolouration and loss of strength of cotton materials and moulding of almost any damp organic substrate.分解纖維素的絲孢綱真菌木材藍(lán)點(diǎn)和軟腐、棉花變色和強(qiáng)度降低、造成任一種潮濕的

34、有機(jī)質(zhì)發(fā)霉。lAscomycetes are prime colonizers and decomposers of soft plant debris, playing a vital role in the carbon and nitrogen cycles. Dominate the soil mycota in most forests. Dead leaves are colonized by aquatic hyphomycetes - tolerant of low temperatures so can grow during the winter and even under ice - make the dead leaves much more palatable and nutritious for the various detritivorous invertebrates whi