Legumes rich in protein are affected by Fusarium oxysporum and Alternaria alternata causing vascular wilt and blight respectively. Exploitation of potent antagonistic microflora is now highly encouraged in effectively controlling and managing plant diseases. In the present study, an attempt is made to reprogram defense mechanism in legumes (Cajanus cajan, Vigna radiata, Vigna mungo) to reduce disease incidence by using Trichoderma viride. Significant plant systemic resistance was achieved in the above legumes against two plant pathogens. Legume seeds treated with T. viride showed 7.52 – 15.40% and 15.20 – 60.00% decrease in disease incidence against F. oxysporum and A. alternata respectively with highest decrease (60%) in V. radiata against pathogen A. alternata. This study clearly demonstrates the physiological stress contributed by amplification of reactive oxygen species (ROS) levels in diseased plants leading to death. However, the prior application of T. viride elevated the levels of ROS, which subsequently alleviate the levels of defense enzymes, antioxidant enzymes and phenols to counter the pathogen infection. This mechanism plays an important role in mitigating pathogen-induced oxidative stress in legumes.
