Overexpression of an aquaglyceroporin gene in Trichoderma harzianum affects stress tolerance, pathogen antagonism and Phaseolus vulgaris development

Aquaporins (AQPs) and aquaglyceroporins (AQGPs) are integral membrane proteins that mediate transport of water and a variety of low molecular weight solutes across biomembranes. We previously identified a gene encoding an AQGPs in Trichoderma harzianum that is up-regulated during biocontrol against Fusarium sp. and has biotechnological applications by improving tolerance to drought stress in transgenic plants. In this study, we report the cloning and overexpression of Thaqp in T. harzianum. Following transformation of T. harzianum via biobalistics, analysis of the resulting transformants showed that their tolerance to salt and osmotic stress was decreased when compared to the wild type. However, enhanced antagonistic activity against Fusarium oxysporum was observed in plate confrontation assays. Furthermore, evaluation of bean development after inoculation with transformants overexpressing Thaqp revealed plants with increased root volume, leaf area and dry weight. Our results underscore the strong potential of aquaglyceroporin in processes such as screening of microorganisms for biological control and molecular breeding of plants.