水稻内生放线菌OsiSh-2发酵滤液诱导宿主抗病性的研究

Endophytic actinomycetes produce diverse secondary metabolites that are crucial in promoting host growth and enhancing resistance to both biotic and abiotic stresses. As a result, they have been widely utilized in biocontrol strategies and the development of antimicrobial agents. In this study, it was found that the cell-free culture filtrate (CFC) of the rice endophytic actinomycete Streptomyces hygroscopicus OsiSh-2 could significantly induce hypersensitive responses in rice and Nicotianabenthamiana, while also promoting the accumulation of H?O? in rice. Moreover, the OsiSh-2 CFC upregulated the expression of immune-related genes in the salicylic acid (SA) and jasmonic acid/ethylene (JA/ET) signaling pathways in rice. Furthermore, it also primed the host into a "defense alert" state, triggering the H?O? signaling cascade at the early stages of Magnaportheoryzae infection, amplifying defense signaling and activating the rice immune system. This resulted in a significant reduction in the disease incidence of rice blast and a decrease in the fungal biomass within rice. Taken together, these findings suggest that the OsiSh-2 CFC enhances rice resistance to M. oryzae by inducing host immune responses.