Plant Volatile Organic Compounds Associated with Fungal Endophyte Seed Treatment of Cotton

Fungal endophytes are endosymbionts of plants. They are generally asymptomatic as opposed to many fungal infections of plants that produce disease. Depending on the strain of endophyte, the fungus can confer benefits to the host plant such as drought tolerance and herbivore resistance. Insect behavioral trials suggest that differences in plant volatile profiles associated with different fungal endophytes affect the host selection behavior of sucking bug pests towards the reproductive structures (squares and bolls) of cotton. We isolated naturally occurring fungal endophytes from field-grown cotton, cultured them in lab, and used their prepared biomass in seed treatments. We performed a qualitative analysis of volatiles emitted from field-grown control and endophyte-treated cotton squares using solid-phase micro-extraction fibers. We also performed quantitative analysis of volatiles emitted from above-ground tissues with Hayesep Q resin. Our results indicate that differences in volatile profiles for endophyte-treated plants are not qualitative.