Endophytes are microorganisms that live in plants without causing any symptoms of disease. A growing body of evidence indicates that many endophytes can confer protection to plants from a variety of stressors and potentially improve yields in major agricultural crops. We have been systematically evaluating the ecological, physiological and agronomic effects of fungal endophytes originally isolated from cultivated cotton (Gossypium hirsutum). Using relatively simple protocols, individual plants can be inoculated with endophytic fungi with resulting phenotypic effects detectable across the entire growing season. Through a combination of greenhouse assays and major field trials, we have demonstrated that the targeted manipulation of fungal endophytes in cotton can mediate resistance to multiple stressors including insects, nematodes and drought, with significant positive impacts on plant performance and yields in the field.
Collaboration with industry partner Indigo Ag has led to the development of commercial products based on the targeted application of microbes to plants. One such product, Indigo Cotton, was launched in 2016 and planted on 50,000 acres across the US cotton belt.
Sword, G.A., Tessnow, A.E. & Ek-Ramos, M.J. (2017) Endophytic fungi alter sucking bug responses to cotton reproductive structures. Insect Science. dos: 10.1111/1744-7917.12461.
Zhou, W., Wheeler, T.A., Starr, J.L., Valencia, C.U. & Sword, G.A. (2016) A fungal endophyte defensive symbiosis affects plant-nematode interactions in cotton. Plant and Soil. doi:10.1007/s11104-016-3147-z.
Lopez, D.C. & Sword, G.A. (2015) The endophytic fungal entomopathogens Beauveria bassiana and Purpureocillium lilacinum enhance the growth of cultivated cotton (Gossypium hirsutum) and negatively affect survival of the cotton bollworm (Helicoverpa zea). Biological Control 89:53-60.
Lopez, D.C., Zhu-Salzman, K., Ek-Ramos, M.J. & Sword, G.A. (2014) The entomopathogenic fungal endophytes Purpureocillium lilacinum (formerly Paecilomyces lilacinus) and Beauveria bassiana can negatively affect cotton aphid reproduction under both greenhouse and field conditions. PLoS ONE 9(8): e103891.
Ek-Ramos, M.J., Zhou, W., Valencia, C.U., Antwi, J.B., Kalns, L.L., Morgan, G.D., Kerns, D.L. & Sword, G.A. (2013) Spatial and temporal variation in fungal endophyte communities isolated from cultivated cotton (Gossypium hirsutum). PLoS ONE 8(6):e66049.
Gurulingappa, P., McGee, P.A. & Sword, G.A. (2011) Endophytic Lecanicillium lecanii and Beauveria bassiana reduce the survival and development of Aphis gossypii following contact with conidia and secondary metabolites. Crop Protection 30:249-352.
Gurulingappa, P., McGee, P.A. & Sword, G.A. (2011) In vitro and in planta compatibility of insecticides and the endophytic entomopathogen, Lecanicillium lecanii. Mycopathologia 172:161-168.
Gurulingappa, P., Sword, G.A., Murdoch, G. & McGee, P.A. (2010) Colonization of crop plants by fungal entomopathogens and their effects on two insect pests when in planta. Biological Control 55:34-41.