Rebecca J. Nelson (born 1961 [1] ) is an American biologist and a professor at Cornell University and a MacArthur Foundation Fellow.
Her work focuses on natural genetic diversity for disease resistance in maize. [2]
Nelson's parents were researchers at the National Institutes of Health. Rebecca holds a BA degree from Swarthmore College, 1982 and a Ph.D. in Zoology from the University of Washington, 1988. She is married to public radio journalist Jonathan Miller [3] and has two children, William and Benjamin.
Nelson began her career at the International Rice Research Institute in the Philippines between 1988 and 1996. From 1996 to 2001, Nelson led the late blight program at the International Potato Center in Lima, Peru starting in 1996. In 1998, Rebecca was named a MacArthur Foundation Fellow for her work in combating rice diseases and potato blight. [4] [5]
In 2001, Nelson became Professor of Plant Pathology & Plant-Microbe-Biology, Plant Breeding & Genetics and International Agriculture & Rural Development at Cornell University. Rebecca teaches an undergraduate course on "Perspectives in International Agriculture and Rural Development" and contributes to other courses in international agriculture and plant pathology. Her research laboratory, based at Cornell University, collaborates with maize geneticists and breeders at Cornell, in Kenya and elsewhere. Ongoing research includes analyzing the genetic architecture of quantitative disease resistance and dissecting quantitative trait loci to identify mechanisms and genes that impair pathogen development, with a particular interest in multiple disease resistance and mycotoxin resistance. [6]
The potato is a starchy root vegetable native to the Americas that is consumed as a staple food in many parts of the world. Potatoes are tubers of the plant Solanum tuberosum, a perennial in the nightshade family Solanaceae.
Plant pathology or phytopathology is the scientific study of plant diseases caused by pathogens and environmental conditions. Plant pathology involves the study of pathogen identification, disease etiology, disease cycles, economic impact, plant disease epidemiology, plant disease resistance, how plant diseases affect humans and animals, pathosystem genetics, and management of plant diseases.
Phytophthora infestans is an oomycete or water mold, a fungus-like microorganism that causes the serious potato and tomato disease known as late blight or potato blight. Early blight, caused by Alternaria solani, is also often called "potato blight". Late blight was a major culprit in the 1840s European, the 1845–1852 Irish, and the 1846 Highland potato famines. The organism can also infect some other members of the Solanaceae. The pathogen is favored by moist, cool environments: sporulation is optimal at 12–18 °C (54–64 °F) in water-saturated or nearly saturated environments, and zoospore production is favored at temperatures below 15 °C (59 °F). Lesion growth rates are typically optimal at a slightly warmer temperature range of 20 to 24 °C.
Blight is a specific symptom affecting plants in response to infection by a pathogenic organism.
Oryza sativa is the much more common of the two rice species cultivated as a cereal, the other species being O. glaberrima, African rice. It was first domesticated in the Yangtze River basin in China 13,500 to 8,200 years ago.
Magnaporthe grisea, also known as rice blast fungus, rice rotten neck, rice seedling blight, blast of rice, oval leaf spot of graminea, pitting disease, ryegrass blast, Johnson spot, neck blast, wheat blast and Imochi (稲熱), is a plant-pathogenic fungus and model organism that causes a serious disease affecting rice. It is now known that M. grisea consists of a cryptic species complex containing at least two biological species that have clear genetic differences and do not interbreed. Complex members isolated from Digitaria have been more narrowly defined as M. grisea. The remaining members of the complex isolated from rice and a variety of other hosts have been renamed Magnaporthe oryzae, within the same M. grisea complex. Confusion on which of these two names to use for the rice blast pathogen remains, as both are now used by different authors.
Steven Dale Tanksley is the Chief Technology Officer of Nature Source Improved Plants. Prior to founding Nature Source Improved Plants, Tanksley served as the Liberty Hyde Bailey professor of plant breeding and biometry and chair of the Genomics Initiative Task Force at Cornell University College of Agriculture and Life Sciences. He is currently a Professor Emeritus at Cornell University.
Spot blotch is a leaf disease of wheat caused by Cochliobolus sativus. Cochliobolus sativus also infects other plant parts and in conjunction with other pathogens causes common root rot and black point.
Rhizoctonia solani is a species of fungus in the order Cantharellales. Basidiocarps are thin, effused, and web-like, but the fungus is more typically encountered in its anamorphic state, as hyphae and sclerotia. The name Rhizoctonia solani is currently applied to a complex of related species that await further research. In its wide sense, Rhizoctonia solani is a facultative plant pathogen with a wide host range and worldwide distribution. It causes various plant diseases such as root rot, damping off, and wire stem. It can also form mycorrhizal associations with orchids.
Marker assisted selection or marker aided selection (MAS) is an indirect selection process where a trait of interest is selected based on a marker linked to a trait of interest, rather than on the trait itself. This process has been extensively researched and proposed for plant- and animal- breeding.
Plant disease resistance protects plants from pathogens in two ways: by pre-formed structures and chemicals, and by infection-induced responses of the immune system. Relative to a susceptible plant, disease resistance is the reduction of pathogen growth on or in the plant, while the term disease tolerance describes plants that exhibit little disease damage despite substantial pathogen levels. Disease outcome is determined by the three-way interaction of the pathogen, the plant and the environmental conditions.
Pamela Christine Ronald is an American plant pathologist and geneticist. She is a professor in the Department of Plant Pathology and conducts research at the Genome Center at the University of California, Davis and a member of the Innovative Genomics Institute at the University of California, Berkeley. She also serves as Director of Grass Genetics at the Joint BioEnergy Institute in Emeryville, California. In 2018 she served as a visiting professor at Stanford University in the Center on Food Security and the Environment.
Xanthomonas oryzae pv. oryzae is a bacterial pathovar that causes a serious blight of rice, other grasses, and sedges.
A genetically modified potato is a potato that has had its genes modified, using genetic engineering. Goals of modification include introducing pest resistance, tweaking the amounts of certain chemicals produced by the plant, and to prevent browning or bruising of the tubers. Varieties modified to produce large amounts of starches may be approved for industrial use only, however, not for food.
Robert S. Dickey was an American phytopathologist, professor emeritus of Plant Pathology at the Cornell University and the namesake of the bacterial genus Dickeya.
The Vertifolia effect is a well documented phenomenon in the fields of plant breeding and plant pathology. It is characterized by the erosion of a crop’s horizontal resistance to disease during a breeding cycle due to the presence of strong vertical resistance, characterized by the presence of R genes. This effect was observed in late blight of potato. This phenomenon was first described by J.E. Van der Plank in his 1963 book Plant Disease: Epidemics and Control. Van der Plank observed that under artificial selection the potato variety Vertifolia had stronger vertical resistance to the potato late blight pathogen, Phytophthora infestans, as measured by the presence of specific R genes. However, when the pathogen overcame these R genes Vertifolia exhibited a greater loss of horizontal resistance than varieties with fewer R genes and lower vertical resistance. This effect suggests that when a pathogen evolves an avirulence gene to counteract a variety’s R gene, that variety will be more susceptible to the pathogen than other varieties.
Molly Jahn is an American plant geneticist and breeder and Professor of Agronomy at University of Wisconsin-Madison, USA. She was Under Secretary of Research, Education and Economics in the U.S. Department of Agriculture.
2Blades is an agricultural phytopathology non-profit which performs research to improve durable genetic resistance in crops, and funds other researchers to do the same. 2Blades was co-founded by Dr. Roger Freedman and Dr. Diana Horvath in 2004.
Samuel S. Gnanamanickam is an Indian plant pathologist. He is known for his research on diversity of rice pathogens, molecular breeding of indica rices for disease resistance and for developing superior strains of beneficial strains of rhizosphere bacteria for biological control of rice diseases. He is a fellow of the National Academy of Agricultural Sciences and National Academy of Biological Sciences of India and was Chair of the biological control committee at the American Phytopathological Society.
Awais Khan is a Pakistani-American plant geneticist and an associate professor at the College of Agriculture and Life Sciences, Cornell University.