哈茨木霉对黄瓜尖孢镰刀菌的抑制作用和抗性相关基因表达

采用室内筛选与田间防效相结合的方法,对哈茨木霉抑制黄瓜尖孢镰刀菌的拮抗机制进行了研究。对峙培养结果显示,木霉菌和病原菌间均形成了较明显的抑菌圈,对病原菌的抑菌率达66.7%~85.8%,其中菌株TG、TM对枯萎病菌抑制作用较强。木霉菌可有效提高根系对病原菌的抗性,黄瓜植株接种枯萎病菌后,根系细胞大量死亡,而先接种木霉菌再接种病原菌后则减小了对根系的伤害。田间防效试验结果表明,TG和TM孢子悬浮液浓度在108个/mL时防效最好,分别为54.9%和49.4%。接种木霉菌植株根系抗性基因的表达量均高于对照植株,呈双峰趋势。在第6天时抗性基因表达量最高,WRKY6、MYB、PR-1、PAL、GST和GLU的表达量分别为对照的5.15、5.22、6.07、6.00、3.16、和16.15倍。表明木霉菌通过激活与胁迫相关的基因表达提高了对病原菌的抗性。

Antagonism effect of Trichoderma harzianum againstFusarium oxysporum on cucumber and related genes expression analysis

The antagonism mechanisms between Trichoderma harzianum and cucumber Fusarium wilt were analyzed combined with indoor selection and field efficacy. There were distinctly inhibition effects to Fusarium spp. in all seven testing strains through the confrontation test, the inhibition rate range from 66.7% to 85.8%. TM and TG behaved best in all the tested strains. Trichoderma harzianum effectively enhanced root resistance to Fusarium wilt. A great deal of root cell died when infection by F.oxysporum. But the injury caused to roots decreased if pre-inoculated with T.harzianum. Field efficacy trials showed that the best induced effects were obtained when the concentration of spores suspension were 10⁸ per milliliter. The best control effect of TG and TM were 54.9% and 49.4% respectively. The resisted gene expression levels inoculated with T.harzianum were higher than that of the control. It appeared two peak values in the second day and the sixth day in the process. The expression in the six day was higher than that in the second day. The expression levels of WRKY6, MYB, PR-1, PAL, GST and GLU were 5.15, 5.22, 6.07, 6.00, 3.16 and 16.15 times of the control respectively. It showed that T.harzianum possessed strong competition ability and invoked a range of related genes to enhance the resistance to pathogen.