Priming effect of chitosan on induces protection against tomato root wilt disease mediated through upregulation of defense enzymes

Abstract

The antifungal activity of chitosan against Sclerotinia sclerotiorum, the causal agent of tomato wilt was investigated. Chitosan was used at 0.2%, 0.4%, and 0.6% concentration in a potato dextrose agar and potato dextrose broth media inhibited S. sclerotiorum growth after ten days (p < 0.05). In vitro antifungal analysis confirmed membrane damage and increased lipid peroxidation reaction in chitosan-treated fungal mycelia than control (p < 0.05). The tomato seeds treated with chitosan registered a significant improvement in seed germination, growth profile and biosynthesis of defense enzymes, chitinase and b-glucanase in tomato seedlings. Tomato seeds treated with 0.3%, and 0.4% chitosan exhibited a significant increase in tomato seed germination rates at 87.4 ± 2.4%, 97.8 ± 4.7%, respectively (p < 0.05). In addition, chitosan-treated tomato seedlings registered upregulation of peroxidase, polyphenol oxidase, phenylalanine ammonia-lyase activity, catalase and β-1, 3 glucanase activity (p < 0.05). Tomato seeds treated with chitosan improved disease protection against wilt disease and maximum protection (85.7 ± 3.2%) was achieved at 0.5% treatment (p < 0.05). Chitosan (0.5%) treated tomato seeds improved shoot length (4.9 ± 0.1), root length (3.5 ± 0.2), and plant biomass (0.428 ± 0.24 g). Chitosan exhibited antifungal activity and defense response on wilt disease and improved plant growth-promoting activities.