Impact of Trichoderma application on tomato rhizosphere bacterial community

Trichoderma species are commonly used to control soilborne pathogens of various crops. However, their biocontrol efficacy often varies. Although many factors (and their interactions) can influence their biocontrol efficacy, soil bacterial community could play a major role (ex: antagonists and synergists). Further, the impact of Trichoderma on the soil bacterial community is not well known. The objectives of the current study were to (i) identify tomato rhizosphere bacterial taxa that could either positively or negatively interact with Trichoderma virens (Tv) and T. harzianum (Th), particularly when they applied to soil individually and in combination (Tv + Th = Tvh), (ii) determine whether the application of Tv, Th, and Tvh differentially alters the tomato rhizosphere bacterial community structure (ex: beta and alpha diversity, the relative abundance of major bacterial phyla and genera), and (iii) investigate if Tv, Th, and Tvh positively/negatively affect the abundance of potentially harmful (ex: phytopathogens, denitrifiers) and beneficial (ex: symbiotic/free-living nitrogen fixers, nitrifiers, biocontrol agents, plant growth promoters) bacterial genera in the tomato rhizosphere.