綦洋, 李凯旋, 赵紫玥, 章凤玲, 王凤花, 孙瑞波. 黄萎病对棉花根内细菌组成和群落构建的影响[J]. 中国生态农业学报 (中英文), 2024, 32(6): 1−10. DOI: 10.12357/cjea.20240026
引用本文: 綦洋, 李凯旋, 赵紫玥, 章凤玲, 王凤花, 孙瑞波. 黄萎病对棉花根内细菌组成和群落构建的影响[J]. 中国生态农业学报 (中英文), 2024, 32(6): 1−10. DOI: 10.12357/cjea.20240026
QI Y, LI K X, ZHAO Z Y, ZHANG F L, WANG F H, SUN R B. The impact of Verticillium wilt on community composition and assembly of cotton root endotrophic bacteria[J]. Chinese Journal of Eco-Agriculture, 2024, 32(6): 1−10. DOI: 10.12357/cjea.20240026
Citation: QI Y, LI K X, ZHAO Z Y, ZHANG F L, WANG F H, SUN R B. The impact of Verticillium wilt on community composition and assembly of cotton root endotrophic bacteria[J]. Chinese Journal of Eco-Agriculture, 2024, 32(6): 1−10. DOI: 10.12357/cjea.20240026

黄萎病对棉花根内细菌组成和群落构建的影响

The impact of Verticillium wilt on community composition and assembly of cotton root endotrophic bacteria

  • 摘要: 大丽轮枝菌是一种土传半活体营养型植物病原真菌, 其引起的黄萎病是影响我国乃至世界棉花生产的最主要因素之一。植物根内微生物种类繁多, 对病原菌有重要的抵御作用。但目前对于病原菌感染影响植物根内微生物组成和群落构建的生态机制尚缺乏深入了解。本研究通过结合可培养和不可培养技术, 研究了健康棉花植株和患黄萎病棉花植株根内细菌物种组成、多样性和群落构建的变化。结果发现, 发病棉花根际细菌群落多样性与健康菌株相比无显著变化, 但是物种组成发生了显著改变, 表现为变形菌门、拟杆菌门与厚壁菌门相对丰度的增加和放线菌门、疣微菌门与粘菌门相对丰度的减少。在所有检测到的4579个zOTU中, 83%的zOTU是两个处理共有的, 但是它们的相对丰度在两个处理中发生了较大变化, 这是引起根内细菌群落变化的主要因素。指示物种分析(ISA)结果显示, 健康棉花植株根内富集了假单胞菌属、红环菌科、莫拉氏菌科等类群, 而患病植株根内富集了假单胞菌属、贪噬菌属和丛毛单胞菌科的物种和根癌农杆菌等。在两组处理的棉花根内均检测到了大丽轮枝菌的拮抗菌ABLF-8菌株, 但其相对丰度在患病植株中显著低于健康植株。Beta-NTI和beta零模型分析结果显示确定性过程主导了棉花根内微生物群落的构建, 但是其贡献在患病植株中显著降低, 说明患病植株根内微生物群落组成的随机性更强。以上结果说明, 大丽轮枝菌侵染直接或间接地降低了棉花对根内微生物群落构建的影响, 引起了大丽轮枝菌拮抗菌相对丰度的显著降低, 从而导致根内微生物菌群的失衡, 降低了根内微生物群落对大丽轮枝菌的拮抗能力, 这可能是棉花黄萎病进一步发展的重要作用机制之一。

     

    Abstract: Verticillium dahliae is a soil-borne, semi-living, vegetative, plant pathogenic fungus. Verticillium wilt, caused by V. dahlia, is one of the most important issues affecting cotton production worldwide. Root endophytes play an important role in plant resistance to pathogenic fungi. However, the impact of Verticillium wilt on the community composition and assembly of endophytic bacteria remains poorly understood. In this study, based on a long-term field experiment, changes in bacterial taxonomic composition, diversity, and community assembly processes in the roots of healthy and Verticillium wilt-diseased cotton plants were investigated using both cultivation-dependent and cultivation-independent technologies. High-throughput sequencing results showed that the diversity of the root endophytic bacteria was not significantly different between the two treatments. However, the taxonomic composition and community structure of the endophytic bacteria in diseased plant roots were significantly different from those in healthy plants. Compared with healthy plants, diseased plants contained significantly higher relative abundance of Proteobacteria, Bacteroidetota, and Firmicutes but lower relative abundance of Actinobacteriota, Verrucomicrobiota, and Myxococcota. Among the 4579 zOTUs detected in this study, 83% were shared between the two treatments; however, the relative abundance of these shared zOTUs was significantly different between the two treatments, which mainly contributed to the dissimilarity of bacterial communities between the two treatments. The biomarker species of the two treatments were identified using indicator species analysis (ISA). The healthy plants enriched zOTUs were assigned as Pseudomonas, Rhodocyclaceae, Moraxellaceae, and unidentified taxa in the roots, whereas the diseased plants enriched different zOTUs were assigned as Pseudomonas, Variovorax, Comamonadaceae, and Agrobacterium tumefaciens. An antagonistic bacterial strain, ABLF-8 (designated Pseudomonas), against V. dahliae was detected in the roots of both healthy and diseased cotton plants. However, its relative abundance was significantly lower in diseased plants than in healthy plants, indicating that the antagonistic effect against V. dahliae in the root endophytic bacterial community of diseased cotton plants was lower than that in healthy plants. The results of the beta-NTI and beta-null model analyses showed that the deterministic process dominated the bacterial community assembly in cotton roots; however, its contribution was significantly lower in diseased plants than in healthy plants, indicating that the randomness of bacterial community assembly in diseased plant roots was higher than that in healthy plant roots, and the regulation of endophytic bacterial communities by plant roots was weakened by Verticillium wilt. In summary, the results of this study indicated that V. dahliae infection directly or indirectly reduced the effect of cotton on the assembly of bacterial communities in roots and caused a significant decrease in the relative abundance of antagonistic taxa against V. dahliae. This led to an imbalance of microbial flora in roots and reduced the antagonism of the endophytic microbial community against V. dahliae, which may be one of the important reasons for the further development of Verticillium wilt.

     

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