|GALE, CODY - Texas A&M University|
|LESNE, PIERRE - Texas A&M University|
|WILSON, CAROLINE - Texas A&M University|
|KRAMER, ZOEY - Texas A&M University|
|MADAMBA, CHRISTINE - Texas A&M University|
|SWORD, GREGORY - Texas A&M University|
Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/17/2021
Publication Date: 6/29/2021
Citation: Gale, C.C., Suh, C.P., Perez, J.L., Lesne, P., Wilson, C., Kramer, Z., Madamba, C., Sword, G.A. 2021. Sampling volatile organic compounds from individual cotton leaves to test effects of fungal endophyte treatments. Southwestern Entomologist. 46(2):299-304. https://doi.org/10.3958/059.046.0201.
Interpretive Summary: Facultative fungal endophytes are unspecialized fungi that can colonize plant tissues without causing symptoms of disease. Recent studies revealed that some species of fungal endophytes can enhance cotton plant defense against insect pests by repelling or deterring insects from feeding on plants. However, the mechanism or this deterrence is unknown. We examined changes in emission of volatile organic compounds (VOCs) from cotton plants treated with or without fungal endophytes before and following insect herbivory. Although the relative abundance of VOCs was significantly affected by herbivory, fungal endophyte treatments had negligible impact on the profile of VOCs emitted from plants. These results suggest that some other factor besides VOC emissions is likely responsible for the enhanced herbivore resistance previously observed on fungal endophyte-treated cotton plants.
Technical Abstract: Facultative fungal endophytes are unspecialized plant-associated fungi capable of colonizing plant tissues without causing symptoms of disease. Studies suggest facultative fungal endophytes enhance cotton (Gossypium hirsutum L.) plant defense against insect herbivores and might alter emissions of volatile organic compounds. We tested for changes in emissions of volatile organic compounds using cotton plants treated with facultative fungal endophtytes Beauveria bassiana (Balsamo-Crivelli) Vuillemin strain GHA and Phialemonium inflatum (Burnside) strain TAMU490 in the presence and absence of herbivory. Solid-phase micro-extraction was used to sample static headspace of individual leaves in collection chambers designed specifically for the experiment. Relative abundance of volatile organic compounds was significantly affected by herbivory, but differences caused by treatment with B. bassiana or P. inflatum were not significant. Findings showed our sampling method can be used to assess constitutive and herbivore-induced volatile organic compound profiles from individual leaves, but further studies need to investigate mechanisms underlying facultative fungal endophyte-mediated herbivore resistance in cotton.