Abstract: Preliminary tests showed the endophytic bacterium DZSY21 isolated from Eucommia ulmoides could colonize in maize, and the resistance of maize to Bipolaris maydis was enhanced by colonization of DZSY21. In this study, the resistance-related enzymes activity and signal transduction pathways were investigated to clarify the mechanism of maize systemic resistance triggered by the endophytic bacterium DZSY21. After leaves treated with DZSY21, the activities of PPO, POD and PAL of the maize leaves increased at 3-10 days. Meanwhile, the defense gene PR-1 in salicylic acid(SA) signaling pathway and the gene LOX in jasmonic acid (JA) signaling pathway were expressed continuously at 24-60 h and 12-60 h, respectively. Accordingly, the DZSY21 was capable of inducing systemic resistance in maize plants. In summary, the application of the endophytic bacterium DZSY21 could trigger maize systemic disease resistance which plays an important role in the control of Bipolaris maydis.

Key words: endophytic bacterium, maize, defense enzymes, signal pathway