Peter J. Cotty was born in Brooklyn, New York. He received his B.S. degree in Biology in 1976 from Boston University, his M.S. degree in Plant Pathology in 1980 from Rutgers University, and his Ph.D. degree in Plant Pathology in 1984 from University of Arizona. After working for 2 years as a Research Associate in the Department of Plant Pathology at the University of Arizona, Cotty joined USDA-ARS in 1986 as a Research Plant Pathologist at the Southern Regional Research Center, New Orleans. In 2003, Cotty transferred his primary research laboratory to the School of Plant Sciences, University of Arizona. He is an Adjunct Professor at his host university.
Cotty is internationally recognized for original insights into population biology, ecology and community structure of aflatoxin-producing fungi and aflatoxin management. Always maintaining both fundamental and field-based applied aspects, Cotty has through critical and original approaches, repeatedly challenged and, when necessary, altered previously accepted paradigms on the etiology and process of aflatoxin contamination and the biology of aflatoxin-producing fungi. His most prominent innovation is use of native atoxigenic strains of Aspergillus flavus to competitively exclude toxigenic strains to limit crop contamination by aflatoxins. After demonstrating aflatoxin production does not increase fungal virulence, Cotty showed both competitive exclusion and competition for nutrients are mechanisms through which atoxigenic strains inhibit aflatoxin production. He developed protocols for selecting safe and effective atoxigenic strains, mycological and molecular methods to track multiple strains simultaneously, and identified the molecular basis of atoxigenicity. Large-scale commercial field studies on tens of thousands of acres proved efficacy of atoxigenic strains. The discovery that native atoxigenic strains can interfere with the contamination process was a revolutionary concept that stimulated a stream of research that led to the evolution of new models and strains for practical control of mycotoxins. Cotty pioneered biological control of aflatoxins and developed new paradigms for technology transfer. When efforts to commercialize atoxigenic strains through conventional industrial links failed, Cotty partnered with Arizona Cotton Research and Protection Council (ACRPC) and IR-4 to secure the first EPA registration of an atoxigenic strain of A. flavus for the management of aflatoxins. This required entering the biopesticide registration process as a registrant with ACRPC and his laboratory becoming an approved pesticide manufacturer. The EPA granted full registration to AF36 based upon Cotty's data and extensive dossier. Cotty and ACRPC designed and engineered a prototype manufacturing facility enabling production of sufficient AF36 to treat 120,000 acres per season. The pioneering registration eased registration of other atoxigenic strains in the U.S. and Africa.
Cotty associated plant pathogen attributes with A. flavus, identified natural variants in virulence, and characterized the molecular basis of that variation while demonstrating that aflatoxin production did not influence fungal virulence to plants, but virulence contributed to isolate capacity to contaminate crops. With postdoctoral associates, Cotty characterized aerial A. flavus communities associated with agriculture in the southwestern US, found human exposure to aflatoxins through consumption of native leguminous seed likely predates agriculture, and pioneered the use of Pyrosequencing in plant pathogen systems.
Cotty altered concepts on adaptation, evolution, and complexity of communities of aflatoxin-producing fungi. He showed variability in aflatoxin producing ability is inherited, not pleomorphic, with toxigenicity highly conserved along certain evolutionary lineages and variable along others suggesting differential adaptive significance among clades; crop infections by A. flavus are complex events frequently caused by multiple genetically distinct individuals, not by a single isolate; evolution of the most important aflatoxin-producing species occurred via ancestral types with S type sclerotia and B & G aflatoxin production. His discovery that acidic conditions trigger high aflatoxin production and inhibit sclerotial morphogenesis stimulated research on both pH regulation and the molecular basis for interrelationships between aflatoxin biosynthesis and sclerotial morphogenesis. Cotty delineated morphotypes of aflatoxin-producing fungi and described their distributions in North America, Africa and Asia while demonstrating the most important contributors to aflatoxin risk in various regions and showing that frequently overlooked fungi may be important causal agents of contamination. With student Claudia Probst, he established fungi with the S-strain morphotype as the "killer maize fungus" responsible for aflatoxicosis-related deaths of over 200 people in Kenya. His work suggests competitive displacement requires locally adapted strains for optimal long-term effects and that management practices should address characteristics of the most important causal agent. With Merritt Nelson, Ramon Jaime-Garcia, and others, Cotty used geostatistics to study the epidemiology of contamination and the population biology of aflatoxin producers and to associate specific producers with regions with increased risk of contamination. Cotty's group provided one of the first clear indications of the potential role of climate change in altering fungal community structure and thereby aflatoxin risk.
Cotty is a superb mentor of students providing them emotional support but demanding scientific excellence. He has individual weekly meetings with his graduate students AND undergraduates with independent projects. He considers undergraduates the "center of his lab". Cotty encourages his undergraduate researchers to handle core microbiological research projects. He also strongly encourages his students (both graduate and undergraduate) to present talks at various scientific meetings where they routinely win awards for their presentations. Because of his exceptional mentorship, the Graduate and Professional Student Council, University of Arizona, recognized Cotty as an Outstanding Faculty Member (2007), an unusual honor for an adjunct faculty who does not formally 'teach'.
Cotty has received numerous awards for his basic research as well as persistent, creative, and effective efforts to secure successful transfer and utilization of technology to manage aflatoxin-producing fungi. These include two Outstanding Scientist Awards (Southern Regional Research Center), Early Career Scientist Award (ARS), Secretary's Award for Personal and Professional Excellence (USDA, group award to T. E. Cleveland, D. Bhatnagar and Cotty), Technology Transfer Award (ARS), Industry Appreciation Award (Arizona Cotton Growers Association), two Environmental Technology Awards (Arizona Farm Bureau Federation), and two Excellence in Technology Transfer Awards (Federal Laboratory Consortium for Technology Transfer). An internationally known expert on Aspergillus and aflatoxin management, Cotty has received numerous invitations to speak in workshops, symposia, and consultations. He served APS as Chairs of the Postharvest Pathology and Mycotoxicology, Mycotoxin, and Biological Control Committees, and Associate Editor of Plant Disease.