Influence of Seed Biopriming and Vermiwash Treatment on Tomato Plant's Immunity and Nutritional Quality upon Sclerotium rolfsii Challenge Inoculation

Tomato is an important nutritional vegetable crop and its nutrient contents are affected by both biotic and abiotic stresses. The main objective of this study was to determine the effect of seed biopriming with Trichoderma pseudokoningii BHUR2 and vermiwash treatment on nutrient content of tomato and defense response against Sclerotium rolfsii under heat stress condition. The combined application of T. pseudokoningii BHUR2 and vermiwash increased fresh weight of root (4.8-fold) and shoot (5.8-fold), dry weight of root (6.9-fold) and shoot (6.4-fold) and number of fruits per plant (4.2-fold) as compared to control under S. rolfsii inoculated condition. Plants treated with T. pseudokoningii BHUR2 and vermiwash exhibited higher defense response against S. rolfsii, mediated by higher activity of superoxide dismutase (3.57-fold), peroxidase (2.05-fold) and phenylalanine ammonia lyase (2.98-fold) enzymes and accumulation of total phenol content (5.35-fold) as compared to control plants. In addition, combined treatment was found to have a positive impact on nutritional status (N, P, K and Ca and lycopene, total soluble sugar and total protein) in tomato fruit. These results suggest potential of T. pseudokoningii BHUR2 and vermiwash in enhancing tomato immunity against S. rolfsii under heat stress condition, which was due to (1) induction in the antioxidant activity and phenylpropanoid pathway, which minimize oxidative damage and reduce pathogen infection and (2) significant improvement in nutrient content leads to better plant growth. The formulation of Trichoderma BHUR2 can be used for field application to mitigate heat stress in plants.