There is a large group of filamentous fungi that inhabit the soil where they form close associations with plant roots. This association can lead to the induction of a systemic resistance response by the plant host towards pathogens. However, the compounds produced by these soil-inhabiting fungi that initiate this response are largely unknown. Two candidate compounds include proteins (called peptaibols) that alter host membrane structures and hydrophobic proteins that are involved in adhesion or host surface recognition. The cloning and characterization of one gene that encodes for production of peptaibols and another gene the encodes for a hydrophobic-like protein from the biological control fungus, Trichoderma virens, are the basis for an approach to test whether these compounds are critical for the induction of plant resistance. The approach is to apply synthesized peptaibols, purified hydrophobic-like protein from T. virens, or genetically modified strains (disrupted or over-expressing the target genes) of T. virens to cotton seedlings in a unique hydroponic system. These treated seedlings will then be challenged by a plant pathogen. Such a tripartite system will provide a mechanism for analyzing the interaction that defines induced plant resistance. An understanding of the host response to these inducing compounds will also contribute to defining how avirulent fungi such as T. virens have developed as commensals rather than plant pathogens. As these two genes are novel to a group of fungi that colonize and interact with numerous plant species, defining their function in the life cycle of T. virens will greatly enhance our understanding the role these fungi play in maintaining ecosystem health.
This project presents a significant opportunity for training undergraduates, graduate students and postdoctoral research scientists in the complex, but intriguing area of microbe-plant-pathogen interactions. Undergraduate students selected from the BioEnvironmental Sciences program will participate in research employing contemporary techniques in fungal and plant molecular biology and digital imaging as they develop independent research projects. A new course being developed by the PI will provide an introduction to undergraduate research and internships to enhance the BioEnvironmental Sciences curriculum.
