Efficacy of plant growth promoting microbes in inducing systemic resistance to root rot and physiochemical properties of tomato fruit

Tomato production and quality are of great economic importance, but farmers face significant losses due to root rot infection, which affects tomato yield. Globally, a wide range of chemical pesticides are used to control plant diseases that have an impact on the environmental and nutritional content of the crop. In this scenario, plant growth-promoting microorganisms (PGPMs) are safe and effective substitutes for the control of root infections. In this study, we have investigated the effect of different plant growth promoting microorganisms (PGPMs) on the suppression of root rot disease in tomato plants. In field plot experiments, conducted in the season I and repeated in season II, the application of PGPMs improved the systemic resistance of plants against root rot pathogens via improving the functioning of antioxidant molecules. They considerably reduced the infection caused by Macrophomina phaseolina, Rhizoctonia solani, Fusarium solani, and Fusarium oxysporum compared to untreated control plants. Isolates of PGPMs significantly (p<0.05) enhanced the amount of total phenol, and salicylic acid with an improvement in crop yield and quality of fruit (dry matter, soluble solids, fruit acidity, and lycopene content). In season I, Penicillium (Pen1-R) whereas in season II, Trichoderma (ET-6) treated plants produced the highest quality of tomato fruit with better plant growth and suppression of root rot disease. In both seasons, Penicillium and Trichoderma were found to be effective as compared to untreated control plants and plants treated with carbendazim, a commercial fungicide. This research will help to make an impact on the production of tomatoes in a sustainable way. (author)