小麦赤霉病生防菌DZSG23的抗病机制

课题组前期从健康杜仲叶片中分离得到1株内生细菌枯草芽孢杆菌DZSG23,此菌可以较好地防控小麦赤霉病。为明确芽孢杆菌DZSG23在小麦中的定殖与强化抗病机制研究,利用抗生素标记法分析了DZSG23菌体在小麦组织中的定殖情况,采用荧光定量PCR技术检测不同生育期小麦穗部PR-1、AOS、ACOI等基因的表达水平变化。结果表明,DZSG23可在苗期小麦植株和小麦穗表面稳定定殖;DZSG23浇灌接种苗期小麦后的第34天,DZSG23在苗期小麦植株的根、茎和叶中的定殖量分别达到1.437×10⁶ CFU·g^-1、3.285×10³ CFU·g^-1和2.377×10³ CFU·g^-1;DZSG23喷施小麦穗表面15 d后,穗表面菌群密度仍可达7.146×10³ CFU·g^-1。此外,诱导系统抗性(ISR)信号通路研究表明,拮抗菌DZSG23可以诱导PR-1和AOS基因的上调表达,表明拮抗菌DZSG23引入小麦后可诱导小麦的...

Resistance mechanism of biocontrol strain DZSG23 against wheat scab

In our previous work, a strain of endophytic bacteria Bacillus subtilis DZSG23 was isolated from the leaves of Eucommia ulmoides Oliv, which could effectively control the wheat scab. This study was carried out to explicit the resistance mechanism of endophytic bacteria DZSG23 against wheat scab.The colonization property of DZSG23 in wheat was analysed by antibiotic label method, then the expression of PR-1, AOS, ACOI, ERF and SAM genes in wheat treated with DZSG23 at different growth stages were detected by quantitative realtime PCR. The results indicated that DZSG23 could successfully colonize wheat plant at seedling stage and surface of the spike. At the 34 d after inoculation with DZSG23 by pouring, the colonization of DZSG23 in roots, stems and leaves of wheat plants at seedling stage reached 1.437×10⁶ CFU·g^-1, 3.285×10³ CFU·g^-1 and 2.377×10³ CFU·g^-1, respectively. After 15 days of inoculation with DZSG23 strain by spraying on the surface of spikes, the surface microbial density of spike tissue still reached 7.146×10³ CFU·g^-1. Expression of defense response genes PR-1 and AOS in wheat spike treated with DZSG23 were significantly higher than those of normal control groups at different growth stages, showing DZSG23 could induce systemic response through SA-and JA-dependent signaling pathways and enhance its disease resistance.