链霉菌TOR3209及其挥发性有机化合物对番茄枯萎病的生防作用和效果

Biocontrol evaluation of Streptomyces TOR3209 and its volatile organic compounds against tomato Fusarium wilt

摘要:

目的 探究链霉菌TOR3209及其挥发性有机化合物(volatile organic compounds, VOCs)对番茄枯萎病的防治效果，分析并挖掘抗病相关差异表达基因，为开发绿色环保的生物农药提供有效策略。方法 设置不同浓度(1.0×10¹、1.0×10³、1.0×10⁵、1.0×10⁷ CFU/mL)的菌株TOR3209菌悬液与番茄共培养，对番茄接种木贼镰孢(Fusarium equiseti)，测定其病情指数；在微型温室中开展菌株TOR3209的VOCs与番茄共培养试验，评估其VOCs对F. equiseti侵染番茄的影响；对抗病效果显著的番茄进行转录组学分析，筛选其VOCs诱导的差异表达基因，并进行实时荧光定量PCR (RT-qPCR)验证。结果 不同浓度的菌株TOR3209菌悬液对番茄枯萎病均具防治效果，其中1.0×10⁷ CFU/mL菌悬液处理的防治效果最好(P<0.01)；不同数量培养有菌株TOR3209的小平皿处理对番茄枯萎病的生防效果与对照组相比差异显著，30个小平皿浓度处理的防治效果最好(P<0.01)；通过转录组分析发现CXE17、LRR-RLK、F-box、TIP1-1 Aquaporin以及Peroxidase等抗病相关基因上调，荧光定量分析表明菌株VOCs与番茄共培养可提升抗病相关基因的表达量，说明转录组测序结果可靠。结论 菌株TOR3209的VOCs通过诱导番茄抗病相关基因上调表达，有效防治F. equiseti侵染导致的番茄枯萎病，为防治枯萎病的生物制剂研发奠定了理论基础。

Abstract:

Objective To explore the control effects of Streptomyces TOR3209 and its volatile organic compounds (VOCs) on tomato Fusarium wilt and mine the differentially expressed genes related to disease resistance, thus providing effective strategies for the development of environmentally friendly biofungicides.Methods Strain TOR3209 suspensions of different concentrations (1.0×10¹, 1.0×10³, 1.0×10⁵, and 1.0×10⁷ CFU/mL) were co-cultured with tomato seedlings, and Fusarium equiseti was inoculated on the seedlings. The disease severity was graded. The co-culture experiment of VOCs from strain TOR3209 with tomato seedlings was conducted in a micro-greenhouse to evaluate the effect of VOCs on tomato seedlings infected by F. equiseti. Transcriptomic analysis was conducted on tomato seedlings with significant disease resistance to mine the differentially expressed genes induced by VOCs, which were then verified by RT-qPCR.Results The suspensions of strain TOR3209 at different concentrations all had control effects on tomato Fusarium wilt. Among them, the 1.0×10⁷ CFU/mL suspension had the best control effect (P<0.01). The biocontrol effects of different quantities of small dishes cultured with strain TOR3209 on tomato Fusarium wilt were significantly different from that of the control group. The group of 30 small dishes showed the best control effect (P<0.01). The transcriptomic analysis showed that the expression levels of disease-resistance genes encoding CXE17, LRR-RLK, F-box, TIP1-1 Aquaporin, and Peroxidase were upregulated. Fluorescence quantitative analysis indicated that co-culture of VOCs from the strain with tomato seedlings upregulated the expression levels of disease-resistance genes, indicating that the transcriptomic sequencing results were reliable.Conclusion The VOCs of strain TOR3209 effectively prevent and control tomato Fusarium wilt caused by F. equiseti infection by inducing the upregulated expression of disease-resistance genes in tomato seedlings. The findings lay a theoretical foundation for the research and development of biofungicides for the prevention and control of Fusarium wilt.