Study on the mechanism of chitosan-induced resistance to black shank in tobacco. Nicotiana tabacum

Chitosan (CTS) can directly inhibit the growth and reproduction of plant pathogenic fungi and bacteria, and induce disease resistance in plants against pathogens, but its intrinsic induction mechanism has not been studied. Tobacco black shank is one of the most destructive diseases in tobacco production.In order to explore the potential mechanism of CTS-induced resistance to P.nicotianae parasiticus, this study pretreated tobacco seedlings with CTS at a concentration of 200 mg/L. The results showed that CTS pretreated tobacco in a 44% reduction in disease incidence and 63.9% reduction in disease index, a significant increase in H2O2, lignin and callose content and SA, JA, and ABA and JA-Ile resistance hormones, and an upregulation of many relevant differentially expressed genes (DEGs) involved in defense responses in CTS pretreated tobacco. Among them, the DEGs in "glutathione metabolism", "MAPK signaling pathway-plant" and "Plant hormone signal transduction" pathways were significantly up-regulated. Based on the results of the experimental physiological indicators and transcriptome, this study proposes and discusses the potential molecular mechanism of chitosan-induced resistance to black shank in tobacco.