Molecular dissection of plant defense responses to necrotrophic pathogens

Purdue University, West Lafayette IN

Investigators

Abstract

Plant diseases caused by necrotrophic pathogens result in losses amounting to millions of dollars a year. Necrotrophic fungi actively kill host tissue prior to colonization usually through the secretion of toxins. This is in contrast to biotrophic pathogens that require living host cells to complete their life cycle. One of the most prevalent and damaging necrotrophs is Botrytis cinerea, a fungal pathogen which causes a variety of pre- and post-harvest diseases in a number of plant species. The principal means of protection against Botrytis is chemical disease control; however, it is seriously hampered by the emergence of fungicide resistance in the pathogen and consumer concern over residual activity in the produce and in the environment. Genetic resistance would be most desirable, but at present it is limited because of paucity of information on genes and mechanisms that underlie host resistance to Botrytis. The goal of this project is to gain insight into the molecular and cellular factors that play a crucial role in defense responses to Botrytis. Through a combination of genetic and genomic approaches many loci that control host response to the pathogen have been uncovered. One of these, BOS1 (Botrytis susceptible 1), was isolated and encodes an R2R3MYB transcription factor required for restricting Botrytis growth in infected plants. This proposal seeks to elucidate the function of BOS1 by determining what genes and pathways it impacts or modulates to regulate an important and relatively less understood arm of the Arabidopsis defense response. This proposal is likely to add tremendously to our understanding of how plants recognize and respond to attack by Botrytis and other necrotrophic fungi, opening the way for future advances in this area. A better appreciation of genes and mechanisms by which plants contend with necrotrophic pathogens will reveal new and effective ways for managing diseases caused by such pathogens. Such knowledge will help direct the breeding of Botrytis resistant cultivars for safe and sustainable crop protection. Ultimately, public safety and environmental quality will be enhanced. In addition, this project will provide ample opportunities for engaging and training students at all levels of education in the principles and applications of genetic, molecular, and plant pathology research, and for enhancing diversity in education.