Functional insight of siderophore in reducing cadmium stress and inducing growth promotion in Solanum melongena

Abstract

Solanum melongena, one of the hyperaccumulator plant, is known to collect a substantial quantity of metal in its edible part. This causes a severe problem for mankind when they consume such type of vegetables. Siderophore has an exceptional ability to chelate Fe with a stronger affinity and other metals including aluminum (Al), Cadmium (Cd), lead (Pb), etc., with a weaker affinity. In the current research, we have evaluated the ability of Trichoderma harzianum siderophore to promote growth of S. melongena by mitigating Cadmium (Cd) stress. Plants inoculated with siderophore have displayed significant outcomes in regards of plant root and shoot length, and high photosynthetic pigments. The level of enzymatic antioxidants (SOD, PAL, CAT, LOX, and PPO) in siderophore-treated plants has been significantly increased in contrast to control and Cd-stressed plants. Siderophore inoculated plant's leaves showed greater accumulation of phenolic compounds (84.38%) as compared to control. Leaves expressed higher flavonoids (67.59%), followed by the stem (44.23%) and roots (45.84%) in siderophore inoculated plants as compared to control. In the case of total phosphomolybdate antioxidants activity and DPPH activity, S. melongena showed plant treated with siderophore has been showed higher total antioxidant activity in comparison to control plant. Moreover, accumulation of secondary metabolites was increased in the trichomes of plants treated with siderophore in contrast to control and Cd-stressed plants. Siderophore was also able to translocate Fe in the presence of Cd in the vicinity. Moreover, accumulation of phenolic compounds and flavonoids (secondary metabolites) was also confirmed though confocal microscopy. All outcomes have emphasized that microbial siderophore can enhance plant growth by decreasing elevated ROS content in Cd stress.