PRELIMINARY ANALYSIS OF THE RESPONSE OF TOBACCO HORMONAL PATHWAY SALICYLIC ACID AND JASMONIC ACID RESISTANCE-RELATED GENES TO EXSEROHILUM TURCICUM

Non-host disease resistance (NHR) is a broad-spectrum disease resistance in plants stimulated by non-adapted pathogenic with persistent disease resistance properties. In recent years, NHR has been considered as a new strategy for disease control. In this study, Aalternaria alternata and E. turcicum were inoculated into the main tobacco varieties Hong Hua Da Jin Yuan (HD) and K326. The expression of disease resistance genes (NtAOS, NtJAZ, NtMYC2) in the upstream and downstream of Jasmonic acid Pathway (JA) and disease resistance genes (NtMAPK, NtPR1, NtPR2, NtPR11) in the upstream and downstream of Salicylic acid Pathway (SA) were analyzed by RT-qPCR. The changes of SOD, POD, PAL enzyme activity and H2O2 content were detected. The results showed that the expression levels of NtMAPK, NtPR1, NtPR2 and NtPR11 were up regulated at 48h after inoculation with A. alternata and E. turcicum, the expression levels of HD and K326 were 1-13 times and 1-38 times higher than those without inoculation, respectively. The expression level of the gene after inoculation with E. turcicum was higher than inoculation with A. alternata; Similar to the SA pathway resistance-related genes, the expression levels of the JA pathway upstream resistance-related gene NtAOS and downstream related genes NtJAZ and NtMYC2 were higher than those in the control and A. alternata stress groups after 48h of E. turcicum stress. The peak of H2O2 content at 12h after E. turcicum stress was higher than that of control and A. alternata stress in the two varieties; Moreover, the activity levels of SOD, POD and PAL at 48h after E. turcicum stress were higher than those under A. alternata stress. In summary, E. turcicum can induce non-host disease resistance in tobacco, enhance the ability of tobacco to resist host pathogens, and reduces or protects tobacco from pathogens to a certain extent.