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Milgroom, Michael Gordon
Cornell Faculty Member
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Positions
- Professor, Plant Pathology and Plant-Microbe Biology (PPPMB), College of Agriculture and Life Sciences (CALS)
My interests are primarily the population biology, genetics and evolution of plant pathogens, with applications to plant disease epidemiology and management. These interests integrate disciplines that are traditionally considered separately in the context of either biology or agriculture.
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Affiliations
member of
- David R. Atkinson Center for a Sustainable Future (ACSF) Faculty Fellow
Research
research overview
- The overall goal of my research program is to understand the population biology and evolution of plant pathogens, and to bridge the gap between population biology and plant disease epidemiology. For much of my career, my research has been aimed at the population genetics of fungi, particularly the chestnut blight fungus, Cryphonectria parasitica, and more recently the grape powdery mildew fungus, Erysiphe necator (formerly Uncinula necator). These fungal pathogens caused devastating epidemics when they were introduced from their native geographic ranges and host populations into new areas with naïve host species. Recent research on both pathogens has been directed towards understanding the history and genetics of these biological invasions. My current research on C. parasitica is focused on the evolution of vegetative incompatibility (vic) genes, which function to prevent heterokaryon formation and are therefore analogous to heterokaryon incompatibility (het) genes of other ascomycete fungi. In collaboration with Don Nuss’s lab at the University of Maryland, we have combined linkage mapping and comparative genomics to identify the genes at four vic loci. Sequence analysis of genes at several of these loci in C. parasitica and three closely related species has revealed that the same alleles are more similar to each other among species than different alleles are within species. This pattern of trans-species polymorphism is indicative of balancing selection acting on these genes to maintain polymorphisms, as found generally for genes involved in non-self recognition. Recent research on E. necator has been directed towards developing genetic and genomic tools for studying its biology. In collaboration with Lance Cadle-Davidson’s lab at the USDA-ARS Grape Genetic Research Unit at Cornell, we have sequenced the transcriptome of E. necator during vegetative growth. We have used this resource to develop microsatellite markers for determining population genetic structure in the eastern US, where this fungus is native. We have also re-sequenced transcriptomes from more than 50 isolates collected throughout the US for analysis of thousands of single-nucleotide polymorphisms (SNPs). With regards to phenotypes, we have quantified the variation in virulence and pathogenicity within E. necator populations in the eastern US and found host specialization on muscadine grapes. Finally, we are investigating the genetics of resistance to demethylation-inhibiting fungicides (DMIs), including studies of sequence polymorphisms and variation in expression of genes known to be involved in DMI resistance. We recently initiated a multidisciplinary project on the impact of aflatoxin on maize in East Africa, funded by the Atkinson Center for a Sustainable Future at Cornell. Aflatoxin is a potent fungal toxin that is highly carcinogenic; it also causes growth retardation and immunosuppression. Aflatoxin is produced by fungi in the genus Aspergillus and affects many seed crops, especially maize and peanuts, in tropical and subtropical regions. This project is being conducted in collaboration with Rebecca Nelson’s lab at Cornell and Biosciences Eastern and Central Africa (BecA) located at the International Livestock Research Institute in Nairobi, Kenya. The main goal of the current project is to determine cost-effective interventions to reduce aflatoxin accumulation in maize in the field and exposure in rural households. The specific research goal in my lab is to understand the ecological significance of aflatoxin production in the ecology and life history of Aspergillus flavus.
research activities
principal investigator on
- POPULATION BIOLOGY OF VERTICILLIUM DAHLIAE awarded by UNIVERSITY OF CORDOBA 2012 - 2013
area(s) of concentration/expertise
keywords
- aflatoxin
- chestnut blight
- fungal genetics
- grape powdery mildew
- mycotoxin
- pathogen population biology
- population genetics of fungi
submitted impact statement
Publications
individual publications
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academic article
- Development of microsatellite markers from the transcriptome of Erysiphe necator for analyzing population structure in North America and Europe. Plant Pathology. 61:106-119. 2012
- Grapevine powdery mildew (Erysiphe necator): a fascinating system for the study of the biology, ecology and epidemiology of an obligate biotroph. Molecular Plant Pathology. 13:1-16. 2012
- Grapevine powdery mildew (Erysiphe necator): a fascinating system for the study of the biology, ecology and epidemiology of an obligate biotroph.. Molecular Plant Pathology. 13:1-16. 2012
- Identification of race-specific resistance in North American Vitis species limiting Erysiphe necator hyphal growth. Phytopathology. 102:83-93. 2012
- Linkage disequilibrium and spatial aggregation of genotypes in sexually reproducing populations of Erysiphe necator.. Phytopathology. 102:997-1005. 2012
- Molecular characterization of vegetative incompatibility genes that restrict Hypovirus transmission in the chestnut blight fungus Cryphonectria parasitica. Genetics. 190:113-127. 2012
- The Chestnut blight fungus world tour : successive introduction events from diverse origins in an invasive plant fungal pathogen.. Molecular Ecology. 21:3931-3946. 2012
- Clonal population structure and introductions of the chestnut blight fungus, Cryphonectria, parasitica, in Asturias, northern Spain. European Journal of Plant Pathology. 131:67-79. 2011
- Differential Gene Expression During Conidiation in the Grape Powdery Mildew Pathogen,Erysiphe necator. Phytopathology. 101:839-846. 2011
- Identification and structure of the mating-type locus and development of PCR-based markers for mating type in powdery mildew fungi. Fungal Genetics and Biology. 48:704-713. 2011
- Variation in virulence of Cryphonectria hypovirus 1 (CHV-1) in Macedonia. Forest Pathology. 41:59-65. 2011
- Genetic stability of Magnaporthe oryzae during successive passages through rice plants and on artificial medium. The Plant Pathology Journal. 26:313-320. 2010
- Genome expansion and gene loss in powdery mildew fungi reveal tradeoffs in extreme parasitism. Science. 330:1543-1546. 2010
- Phylogeography and population structure of the grape powdery mildew fungus, Erysiphe necator, from diverse Vitis species. BMC Evolutionary Biology. 10:268. 2010
- Population Structure and Resistance to Mefenoxam of Phytophthora capsici in New York State. Plant Disease. 94:1461-1468. 2010
- Variation in pathogenicity and aggressiveness of Erysiphe necator from different Vitis species and geographic origins in the eastern United States. Phytopathology. 100:1185-1193. 2010
- Heterokaryons and parasexual recombinants of Cryphonectria parasitica in two clonal populations in southeastern Europe. Fungal Genetics and Biology. 46:849-854. 2009
- Spatial aggregation in Fusarium pseudograminearum populations from the Australian grain belt. Plant Pathology. 58:23-32. 2009
- Speciation of a tropical fungal species pair following transoceanic dispersal. Molecular Phylogenetics and Evolution. 51:413-426. 2009
- Clonal population structure of the chestnut blight fungus in expanding ranges in southeastern Europe. Molecular Ecology. 17:4446-4458. 2008
- Genetic differentiation of Magnaporthe oryzae populations from scouting plots and commercial rice fields in Korea. Phytopathology. 98:436-442. 2008
- Horizontal transmission of hypoviruses between vegetative compatibility types of Cryphonectria parasitica in Macedonia. European Journal of Plant Pathology. 120:35-42. 2008
- Persistence and spatial autocorrelation of clones of Erysiphe necator overwintering as mycelium in dormant buds in an isolated vineyard in northern Italy. Phytopathology. 98:148-152. 2008
- Diversity of viruses in Cryphonectria parasitica and C. nitschkei in Japan and China, and partial characterization of a new chrysovirus species. Mycological Research. 111:433-442. 2007
- Fifty-three polymorphic microsatellite loci in the chestnut blight fungus, Cryphonectria parasitica. Mol Ecol Notes. 7:428-432. 2007
- High diversity of vegetative compatibility types in Cryphonectria parasitica in Japan and China. Mycologia. 99:279-284. 2007
- Relative contribution of seed-transmitted inoculum to foliar populations of Phaeosphaeria nodorum. Phytopathology. 97:584-591. 2007
- Markers linked to vegetative incompatibility (vic) loci and a region of reduced recombination near the mating type locus (MAT) in Cryphonectria parasitica. Fungal Genetics and Biology. 43:453-463. 2006
- Occurrence of Cryphonectria hypovirus 1 in the chestnut blight fungus in Macedonia. Forest Pathology. 36:136-143. 2006
- Genetic diversity in the gypsy moth fungal pathogen Entomophaga maimaiga from founder populations in North America and source populations in Asia. Mycological Research. 109:941-950. 2005
- Genetic similarity of flag shoot and ascospore subpopulations of Erysiphe necator in Italy. Applied and Environmental Microbiology. 71:7788-7791. 2005
- Heterokaryon formation and parasexual recombination between vegetatively incompatible lineages in a population of the chestnut blight fungus, Cryphonectria parasitica. Molecular Ecology. 14:3657-3669. 2005
- Heterokaryon incompatibility function of vegetative incompatibility genes (vic) in Cryphonectria parasitica. Mycologia. 98:43-50. 2005
- Polymorphic sequence-characterized codominant loci in the chestnut blight fungus, Cryphonectria parasitica. Molecular Ecology Notes. 5:195-197. 2005
- Population structure of seedborne Stagonospora nodorum on New York wheat. Phytopathology. 95:300-305. 2005
- Biological control of chestnut blight with hypovirulence: a critical analysis. Annual Review of Phytopathology. 42:311-338. 2004
- Comparison of genetic structures among Cryphonectria parasitica populations from China, Japan and the USA. Scientia Silvae Sinicae. 40:127-131. 2004
- DNA sequence data and morphology define Cryphonectria species in Europe, China and Japan. Can J Bot. 82:1730-1743. 2004
- Low diversity of vegetative compatibility types and mating type in Cryphonectria parasitica in the southern Balkans. Plant Pathol. 53:325-333. 2004
- Mating-type heterokaryosis and selfing in Cryphonectria parasitica. Fungal Genetics and Biology. 41:521-533. 2004
- Mixed mating in natural populations of the chestnut blight fungus, Cryphonectria parasitica. Heredity. 93:189-195. 2004
- Population structure of seedborne Stagonospora nodorum on New York wheat. Phytopathology. 94. 2004
- Recombination and migration of Cryphonectria hypovirus 1 as inferred from gene genealogies and the coalescent. Genetics. 166:1611-1629. 2004
- Spatial and genetic analysis of a flag shoot subpopulation of Erysiphe necator. Phytopathology. 94:544-550. 2004
- Stepwise evolution of races in a plant pathogenic fungus inferred from fingerprinting with repetitive DNA sequences. Phytopathology. 94:228-235. 2004
- Analysis of genotypic diversity data for populations of microorganisms. Phytopathology. 93:738-746. 2003
- Diversity of pathotypes and DNA fingerprint haplotypes in populations of Magnaporthe grisea in Korea over two decades. Phytopathology. 93:1378-1385. 2003
- Evidence for interspecies transmission of viruses in natural populations of filamentous fungi in the genus Cryphonectria. Molecular Ecology. 12:1619-1628. 2003
- Gene genealogies support Fusarium oxysporum f. sp. ciceris as a monophyletic group. Plant Pathology. 51:73-77. 2002
- Persistence of Cryphonectria hypoviruses after their release for biological control of chestnut blight in West Virginia forests. For. Pathol.. 32:345-356. 2002
- Programmed cell death correlates with virus transmission in a filamentous fungus. Proceedings of the Royal Society of London Series B. 269:2269-2276. 2002
- Analysis of mating type genes in the chestnut blight fungus, Cryphonectria parasitica. Fungal Genetics and Biology. 34. 2001
- Genetic control of horizontal virus transmission in the chestnut blight fungus, Cryphonectria parasitica. Genetics. 159:107-118. 2001
- Outcrossing and diversity of vegetative compatibility types in populations of Eutypa lata from grapevines. Journal of Plant Pathology. 83:79-86. 2001
- The mating system of the fungus Cryphonectria parasitica: selfing and self-incompatibility. Heredity. 86:134-143. 2001
- The synthesis of genetics and epidemiology: contributions of population biology in plant pathology. Journal of Plant Pathology. 83:57-62. 2001
- A spatially-structured stochastic model to simulate heterogeneous transmission of viruses in fungal populations. Ecological Modeling. 127:291-308. 2000
- Identification and spread of Fomitiporia punctata associated with wood decay of grapevine showing symptoms of esca disease. Phytopathology. 90:967-972. 2000
- Variation in tolerance and virulence in the chestnut blight fungus-hypovirus interaction. Applied and Environmental Microbiology. 66:4863-4869. 2000
- Analysis of population structure of the chestnut blight fungus based on vegetative incompatibility genotypes. Proceedings at the National Academy of Science USA. 96:10518-10523. 1999
- Origin, genetic diversity, and population structure of Nectria coccinea var. faginata in North America. Mycologia. 91:583-592. 1999
- PCR amplification of the mating type idiomorphs in Cryphonectria parasitica. Molecular Ecology. 8:1947-1950. 1999
- Genetics of vegetative incompatibility in Cryphonectria parasitica. Applied and Environmental Microbiology. 64:2988-2994. 1998
- Incidence and diversity of double-stranded RNAs infecting the chestnut blight fungus, Cryphonectria parasitica, in China and Japan. Phytopathology. 88:811-817. 1998
- Diversity of hypoviruses and other double-stranded RNAs in Cryphonectria parasitica in North America. Phytopathology. 87:1026-1033. 1997
- Potential diversity in vegetative incompatibility types of Ophiostoma novo-ulmi in North America. Mycologia. 89:722-726. 1997
- Amplified fragment length polymorphism (AFLP) fingerprinting of symbiotic fungi cultured by the fungus-growing ant Cryphomyrmex minutus. Mol. Ecol.. 5:119-222. 1996
- Correlation between hypovirus transmission and the number of vegetative incompatibility (vic) genes different among isolates from a natural population of Cryphonectria parasitica. Phytopathology. 86:79-86. 1996
- Distribution and diversity of vegetative compatibility types in subpopulations of Cryphonectria parasitica in Italy. Mycological Research. 100:1087-1093. 1996
- Diversity and multilocus genetic structure in populations of Cryphonectria parasitica. Phytopathology. 86:1344-1451. 1996
- Intercontinental population structure of the chestnut blight fungus, Cryphonectria parasitica. Mycologia. 88:179-190. 1996
- Clonal dispersal and spatial mixing in populations of the plant pathogenic fungus, Sclerotinia sclerotiorum. Mol. Ecol.. 4:69-77. 1995
- Detection of double-stranded RNA in Cryphonectria parasitica (Murr.) Barr with monoclonal antibodies. Acta Phytopathologica Sinica. 25:91-92. 1995
- Fungicide resistance: lessons for herbicide resistance management?. Weed Technology. 9:840-849. 1995
- Genetic correlations in resistance to morpholine and piperidine fungicides in Pyrenophora teres. European Journal of Plant Pathology. 101:93-99. 1995
- Population biology of the chestnut blight fungus, Cryphonectria parasitica. Can. J. Bot. 73. 1995
- Population differentiation in the chestnut blight fungus, Cryphonectria parasitica, in eastern North America. Phytopathology. 85:155-160. 1995
- Spatial analysis of nuclear and mitochondrial RFLP genotypes in populations of the chestnut blight fungus, Cryphonectria parasitica. Molecular Ecology. 4:633-642. 1995
- Genetic structure of Pyrenophora teres populations determined with RAPD markers. Can. J. Bot.. 72:915-923. 1994
- Isolation and characterization of a virus-resistant mutant of the chestnut blight fungus. Curr. Genet.. 26:528-534. 1994
- Lack of correlation between fitness and resistance to sterol biosynthesis-inhibiting fungicides in Pyrenophora teres. Phytopathology. 84:515-519. 1994
- Selection for decreased sensitivity to propiconazole in experimental field populations of Stagonospora nodorum (syn. Septoria nodorum). Can. J. Pl. Path.. 16:109-117. 1994
- Estimation of the outcrossing rate in the chestnut blight fungus, Cryphonectria parasitica. Heredity. 70:385-392. 1993
- Maternal inheritance and diversity of mitochondrial DNA in the chestnut blight fungus, Cryphonectria parasitica. Phytopathology. 83:563-567. 1993
- Comparison of genetic diversity in the chestnut blight fungus, Cryphonectria (Endothia) parasitica, from China and the US. Mycological Research. 96:1114-1120. 1992
- DNA fingerprinting and analysis of population structure in the chestnut blight fungus, Cryphonectria parasitica. Genetics. 131:297-306. 1992
- Inheritance of triadimenol resistance in Pyrenophora teres. Phytopathology. 82:821-828. 1992
- The structure and interrelationship of fungal populations in native and cultivated soils. Mol. Ecol.. 1:241-249. 1992
- Spatial analysis of vegetative compatibility groups in the chestnut blight fungus, Cryphonectria parasitica. Can. J. Bot.. 69:1407-1413. 1991
- A stochastic model for the initial occurrence and development of fungicide resistance in plant pathogen populations. Phytopathology. 80:410-416. 1990
- Quantification of factors influencing potato late blight suppression and selection for metalaxyl resistance in Phytophthora infestans: A simulation approach. Phytopathology. 81:1190-1198. 1990
- Quantification of factors influencing potato late blight suppression and selection for metalaxyl resistance in Phytophthora infestans: A simulation approach. Phytopathology. 80:1190-1198. 1990
- A model for the effects of metalaxyl on potato late blight epidemics. Phytopathology. 78:559-565. 1988
- A simulation analysis of the epidemiological principles for fungicide resistance management in pathogen populations. Phytopathology. 78:565-570. 1988
- Distribution and temporal dynamics of metalaxyl in potato foliage. Phytopathology. 78:555-559. 1988
- A metalaxyl bioassay for a large number of small foliar samples. Phytopathology. 77:237-240. 1987
- Attenuation of metalaxyl on potato leaves by simulated acidic rain and residence time. Phytopathology. 77:401-406. 1987
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article
-
chapter
- Ecology and evolution of fungal viruses. Studies in Viral Ecology: Volume One: Microbial and Botanical Host Systems. 221-257. 2011
- Viruses in fungal populations In Structure and dynamics of fungal populations. Kluwer Academic Publ. 283-305. 1999
- Contributions of population genetics to plant diseases epidemiology and management. Advances in Botanical Research. 1-30. 1997
- Analysis of population structure in fungal plant pathogens. Disease analysis through genetics and molecular biology: Interdisciplinary bridges to improved sorghum and millet crops. 213-229. 1995
- Population genetics and intercontinental migrations of Phytophthora infestans. Annual Review Phytopathol. 107-29. 1992
- Population biology and management of fungicide resistance. Managing Resistance to Agrochemicals. 275-285. 1990
- Population biology and management of fungicide resistance. Managing resistance to agrochemicals. 275-285. 1990
- Population genetics theory and fungicide resistance. Plant disease epidemiology. 340-367. 1989
- Population genetics theory and fungicide resistance. Plant Disease Epidemiology. Vol.2, Genetics, Resistance, and Management. 340-367. 1988
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conference paper
- Genetic variation in the gypsy moth fungal pathogen Entomophaga maimaiga from North America and Asia. Proc. Soc. Invertebr. Pathol., Ann. Mtg., Helsinki. 84. 2004
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document part
-
report
- Population biology of plant pathogens: the synthesis of plant disease epidemiology and population genetics 2003
- Contributions of population genetics to plant disease epidemiology and management 1997
- Genetic variation and the application of genetic markers for studying plant pathogen populations 1997
- Recombination and the multilocus structure of fungal populations 1996
- Population genetics and intercontinental migrations of Phytophthora infestans 1992
Teaching
teaching overview
- My teaching in 2008, 2009 and 2010 was entirely at the graduate level on the topics of population biology and epidemiology of plant pathogens.
teaching activities
- PLPA-4020: Biology of Plant Pathogens - Spring 2013
- PLPA-7980: Graduate Teaching Experience - Spring 2013
- PLPA-7990: Graduate-Level Thesis Research - Spring 2013
- PLPA-8900: Master's Level Thesis Research - Spring 2013
- PLPA-9900: Doctoral-Level Thesis Research - Spring 2013
- PLPA-2950: Biology of Infectious Disease: From Molecules to Ecosystems - Fall 2012
- PLPA-6420: Pathogen Population Biology - Fall 2012
- PLPA-7980: Graduate Teaching Experience - Fall 2012
- PLPA-7990: Graduate-Level Thesis Research - Fall 2012
- PLPA-8900: Master's Level Thesis Research - Fall 2012
- PLPA-9900: Doctoral-Level Thesis Research - Fall 2012
- PLPA-7980: Graduate Teaching Experience - Spring 2012
- PLPA-7990: Graduate-Level Thesis Research - Spring 2012
- PLPA-8900: Master's Level Thesis Research - Spring 2012
- PLPA-9900: Doctoral-Level Thesis Research - Spring 2012
- PLPA-7980: Graduate Teaching Experience - Fall 2011
- PLPA-7990: Graduate-Level Thesis Research - Fall 2011
- PLPA-8900: Master's-Level Thesis Research - Fall 2011
- PLPA-9900: Doctoral-Level Thesis Research - Fall 2011
Service
service to the profession
- Dept. of Ecology and Evolutionary Biology University of Toronto External Examiner for PhD thesis - 2006
- Swedish Agricultural University, Uppsala Reviewer, Program - 2000
- University of Pretoria, South Africa External Examiner for MSc Thesis - 1999
- Dept. of Botany, University of Toronto External Examiner for PhD Thesis - 1996
- NE-140 Regional project on "Biological Improvement of Chestnuts" Chairperson 1992 - 1993
reviewer or editor for
- Molecular Plant Pathology
- NIH Genetics Study Section
- NSF Population Biology grant review panel
- NSF Population Biology grant review panel
- USDA National Research Initiatives Competitive Grants Program review panel for Plant Pathology
- USDA National Research Initiatives Competitive Grants Program review panel for Plant Pathology
Background
education and training
- Ph.D. in Plant Pathology, Cornell University 1987
- M.S. in Biology (Ecology and Evolutionary Biology), University of Michigan 1982
- B.A. in Botany, University of Vermont 1978
awards and honors
- Honorary Fellow, 2010
- Excellence in Multistate Research Award (NE-1033), 2010
- Fulbright Scholarship, 2003
- National Residence Hall Honor, 2000
- USDA Group Honor Award for Excellence, NE Regional Project 140, 1997
- Sigma Xi, 1988
- NSF Predoctoral Fellowship, 1985
- NSF Predoctoral Fellowship, 1985
- Andrew D. White Fellowship, 1985
- NSF Predoctoral Fellowship, 1984
- Andrew D. White Fellowship, 1984
- NSF Predoctoral Fellowship, 1983
- Andrew D. White Fellowship, 1983
- NSF Predoctoral Fellowship, 1982
- Mellon Foundation Naturalist Ecologist Traineeship, 1982
Other
college
- CALS
research keyword
- aflatoxin
- chestnut blight
- fungal genetics
- grape powdery mildew
- mycotoxin
- pathogen population biology
- population genetics of fungi
name prefix
- Professor