Assessing the effects of Trichoderma spp-maize root colonization on multitrophic interactions
In nature, plants deal with myriads of organisms including fungi, bacteria, nematodes, insects and others. Many of these organisms can be either foes or friends to plants. Multiple microbes, e.g., fungi and bacteria often colonize plant tissues internally without demonstrating infection symptoms. They live as symbiotic endophytes within plant tissues providing benefits to the host plant including plant protection against insect pests and pathogens, improvements in nutrient uptake, and raising tolerance to abiotic stresses. Plant root mutualistic microbes are reported to induce systemic resistance against several plant diseases and insect herbivores attacking the host plant. Of the several groups of biocontrol fungi, Trichoderma spp. are commonly used as biological control agents for plant pathogens. This fungus can endophytically colonize plant roots thereby conferring benefits to the host plants in terms of growth enhancement and resistance against biotic and abiotic stresses. Similarly, Trichoderma was recently reported to trigger plant direct and direct defense responses against insect pests and pathogens in certain crop plants by altering plant metabolome and transcriptome.Additionally, plants emit certain herbivore-induced volatiles (HIPVs) compounds in response to herbivore feeding or egg deposition thereby providing cues for the herbivore’s natural enemies to locate their hosts. Natural enemies (parasitoids and predators) are attracted to the victim plant via the blend of these volatiles, playing a significant role in indirect plant defense. However, a number of abiotic and biotic factors including the colonization of the plant by endophytic fungi may affect the quality and quantity of HIPVs, in addition to giving rise to metabolic and transcriptional changes in the host plant’s physiological and biochemical processes. Hence, our research project will elucidate the effects of endophytic colonization of Trichoderma spp on metabolic changes, volatile emissions, phytohormone contents/defence signaling pathways, and herbivore nutrition-related compounds in maize crops and the impacts of these changes on tri-trophic interactions (Trichoderma-maize-herbivore-parasitoid).