lecture 9 - 9/17/10 Introductory Plant Pathology BTNY...

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Unformatted text preview: 9/17/10 Introductory Plant Pathology BTNY 301 R. D. Martyn Fall, 2010 Lecture #9 Fungi as plant pathogens – History and the Oomycota Late blight of potato & tomato RD Martyn, Purdue University 1 Spontaneous GeneraPon Life arises spontaneously from non-life Conclusion: Corn seeds turn into mice! RD Martyn, Purdue University 2 1 9/17/10 Louis Pasteur (1822 – 1895) •  French chemist and microbiologist. •  Known for many important discoveries in microbiology and disease including the first vaccine for rabies and pasteurizaPon of milk and wine to prevent illness. Louis Pasteur, Musee d’Orsay, Paris •  1864  ­ ___________________________________________ – “chicken broth in the goose ­neck flask experiment”. Lead the way for the “germ theory of disease” by R. Koch, et al. in the 1870s. RD Martyn, Purdue University 3 Heinrich Anton de Bary (1831 – 1888) ____________________________ •  1863: Conclusively proved through inoculaPon experiments that __________________ was caused by a _____________; __________________________, 10 years before Robert Koch. •  Microscopically observed spore germinaPon, penetraPon and colonizaPon of plant Pssue. •  First to describe ___________________ in fungi •  Described the heterocyclic life cycle of Puccinia graminis, cause of stem rust of wheat. •  Published over 100 scienPfic papers / books on different plant diseases and their cause. •  Established the science of ‘mycology’ RD Martyn, Purdue University 4 2 9/17/10 Oomycota (Oomycetes) •  If it looks like a duck, walks like a duck, quacks like a duck,… It must be a duck chicken! RD Martyn, Purdue University 5 What are Oomycetes? Three Domain Model Stramenopiles – Somewhere between true fungi and colorless algae RD Martyn, Purdue University 6 3 9/17/10 Rossman, AY & ME Palm. 2007. Why are Phytophthora and other Oomycota not true fungi? hpp://www.apsnet.org/online/feature/oomycetes/ Oomycota •  •  •  •  ________________________ ________________________ Cell walls composed primarily of _______________ VegataPve hypha is _______________ –  1 posterior whiplash –  1 anterior Pnsel (feathery) •  MoPle _____________ with two kinds of __________ RD Martyn, Purdue University 7 Oomycota •  Asexual reproducPon –  _______________________ Cornell IPM Program RD Martyn, Purdue University 8 4 9/17/10 Oomycota •  ____________ reproducPon –  ________________ or ________________ –  ______________(+) and ________________ ( ­) –  Sexual spore is an __________. Also survival spore RD Martyn, Purdue University + 9 MaPng types: Homothallic vs. Heterothallic •  ___________ – producing compaPble male (+) and female ( ­) gametes on the same mycelium. (e.g., complete flower – has both stamens and carpels in the same flower) •  ___________ – producing compaPble male (+) and female ( ­) gametes on physiological disPnct mycelia. (e.g., incomplete flower – stamens and carpels are on different flowers RD Martyn, Purdue University 10 5 9/17/10 Oomycota •  Sexual reproducPon –  Homothallic or heterothallic –  Antheridium (+) and Oogonium ( ­) –  Sexual spore is an oospore. Also survival spore RD Martyn, Purdue University + 11 (Some of most serious plant diseases in history) •  ___________________ –  ____________________________ (Ph. infestans) –  ____________________________ (Ph. ramorum) •  ______________ –  ________________________ (Py. debaryanum) •  ____________________ –  ___________________________ (Plasmopara vi=cola) –  ___________________________ (Pseudoperonospora cubensis) Plant Diseases Caused by Oomycota RD Martyn, Purdue University 12 6 9/17/10 Late blight of potato (Phytophthora infestans) RD Martyn, Purdue University Photographs courtesy of Cornell University IPM Program 13 Late blight of potato Photographs courtesy of Cornell University IPM Program RD Martyn, Purdue University 14 7 9/17/10 Late blight of tomato S. Koike, et al. Vegetable Diseases, Academic Press Photographs courtesy of Cornell University IPM Program RD Martyn, Purdue University 15 Schumann, G.L. and C. J. D’Arcy. 2000. Late blight of potato and tomato. The Plant Health Instructor. DOI: 10.1094/PHI ­I ­2000 ­0724 ­01 hpp://www.apsnet.org/educaPon/LessonsPlantPath/LateBlight/default.htm Late blight of potato Life cycle of _____________________________, casual agent of late blight of potatoes RD Martyn, Purdue University 16 8 9/17/10 The Irish potato famine and the birth of plant pathology hpp://www.apsnet.org/online/feature/lateblit/chapter1/epidemic.htm Late blight of potato Life cycle of Phytophthora infestans, casual agent of late blight of potatoes RD Martyn, Purdue University 17 Late blight of potato •  Disease is favored by ____________condiPons –  Sporangia germinate via ___________ at 12  ­15 C°  ­  Sporangia germinate via a ___________ at ≥ 15 C° RD Martyn, Purdue University 18 9 9/17/10 Late blight – Disease Management •  __________ – remove and destroy infected plants and fruit (P. infestans is an obligate parasite) •  Plant only ___________ tubers, seeds and transplants •  If possible, plant __________________________ (Potato = Elba, Kennebec) •  _________________ – protectants –  Maneb, mancozeb, chlorothalonil, fixed ­coppers RD Martyn, Purdue University 19 _____________________________________ (Phytophthora ramorum) Davidson, J. et al. 2003. Sudden oak death and associated disease caused by Phytophthora ramorum. Online. Plant Health Progress doi:10.1094/PHP ­2003 ­0707 ­01 ­DG. hpp://www.plantmanagementnetwork.org/php/shared/sod/ From California Oak Mortality Task Force From Alan Kanaskie, USDA Forest Service RD Martyn, Purdue University 20 10 9/17/10 Ramorum blight of tan oak RD Martyn, Purdue University From J. Davidson, et al. 21 Ramorum blight of Rhododendron spp. RD Martyn, Purdue University 22 11 9/17/10 Phytophthora ramorum •  Hosts –  __________ (Tan oak, California live oak, Canyon live oak, California black oak, Coastal oak, etc.) –  _____________ –  _________________________ –  _________________________ –  _________________________ –  _________________________ –  Others RD Martyn, Purdue University 23 12 ...
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This note was uploaded on 04/03/2011 for the course BTNY 301 taught by Professor Staff during the Fall '08 term at Purdue University-West Lafayette.

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