哈茨木霉对接种尖孢镰刀菌后黄瓜根系次生代谢物的影响

Effects of Trichoderma harzianum on Secondary Metabolites in Cucumber Roots Infected With Fusarium oxysporum

采用室内筛选与田间试验相结合的方法,对哈茨木霉抑制黄瓜枯萎病菌的拮抗机制进行了研究。对峙培养结果显示木霉菌和病原菌之间形成了较明显的抑菌圈,其中菌株TN对枯萎病菌抑制作用较强。接种木霉菌植株显著提高了植株中肉桂醇脱氢酶(CAD)、多酚氧化酶(PPO)、愈创木酚过氧化物酶(G-POD)、咖啡酸过氧化物酶(CA-POD)和绿原酸过氧化物酶(CGA-POD)的活性及总酚、类黄酮、木质素的含量。接种木霉菌可诱导根系次生代谢相关基因的上调表达,C4H、CAD、CCOMT、G6PDH、PAL和PR-1的表达量分别为对照的5.64、5.31、4.28、15.33、7.36和6.45倍。表明木霉菌诱导的黄瓜根部对枯萎病的抗性与植物次生代谢密切相关。

Interaction between Trichoderma harzianum and cucumber Fusarium wilt pathogen was studied in vitro and in vivo. Three tested isolates of T. harzianum exhibited distinct inhibitory effects on Fusarium in dual tests. Isolate TN showed performed more inhibitively than the other tested isolates. Field inoculation of T. harzianum resulted in enhanced content of flavonoids, phenolics and lignin in cucumber plants. Meanwhile, the activities of CAD, PPO, G-POD, CA-POD and CGA-POD were increased by 100%, 54%, 278%, 143% and 52%, respectively. The expression level of resistance-related genes in plants inoculated with T. harzianum was higher than that of the control. The expression levels of all selected genes but CCOMT were higher on 6 dai （days after inoculation） than those on 2 dai. The expression levels of C4H, CAD, CCOMT, G6PDH, PAL andPR-1 in the T. harzianum colonized plants were 5.64, 5.31, 4.28, 15.33, 7.36 and 6.45 times higher than that in control, respectively. Our findings demonstrated the close relationship between secondary metabolism and the T. harzianum-mediated induced resistance towards Fusarium infection in cucumber roots.