Enhancing resistance of Sesamum indicum against Alternaria sesami through Bacillus velezensis AR1.

Abstract

Considerable yield loss and poor quality of sesame seed are attributed to fungal pathogens including Alternaria sesami. The use of agrochemicals and few biocontrol agents have been employed to at least minimize the problem. Thus, this research work was initiated to mitigate the impact of the disease using Bacillus velezensis AR1. A total of four treatments, A. sesami alone, sole fungicide, AR1, and alternate application of AR1 with dithianon (fungicide) were applied with six replications. The results indicate that the sole and alternate application of AR1 with fungicide reduced disease severity to less than 10%. Plant physiological traits also improved due to the plant growth promoting AR1. Induced plant defense-related biochemicals, i.e. total phenolic and flavonoid contents, were maximum in the plant subjected to AR1 and alternate application with a fungicide. In addition, the concentration of leaf amino acid proline was doubled due to AR1 compared to the control. The concentration of the plant growth-regulating hormones gibberellic acid and indole acetic acid (IAA), as well as leaf chlorophyll, total nitrogen and phosphorus contents were also significantly increased by 203.86, 7.79, 0.31 mg gFW-1 , 0.15 and 0.13%, respectively, due to the treatments. Furthermore, postharvest soil chitinase, cellulase and 1,3-β-glucanase activity results indicated the biological control and rapid soil colonization trends of AR1. From these in vitro and in vivo experiment findings, B. velezensis AR1 can be recommended for biological control of plant fungal diseases for environmentally safe and quality crop production. © 2020 Society of Chemical Industry.