长期稻- 稻- 紫云英轮作对水稻种子内生细菌的 影响及促生功能评价

Seeds are regarded as a reservoir and carrier of beneficial microorganisms. Compared with the rhizosphere and phyllosphere, the research on seed-associated bacteria is still very backward. In this study, the rice seeds of two planting patterns, namely long-term green manure plant and rice rotation (rice-rice-milk vetch, R - R - MV) and winter fallow (rice-rice-winter fallow, R - R - WF), were used as materials to isolate endophytic bacteria in seeds. Based on the phylogenetic analysis of 16S rRNA gene of the strains, representative strains were selected according to the isolation source and taxonomic position to detect plant growth-promoting functions such as phosphorus solubilization, IAA production and siderophore production. The results showed that the number of endophytic bacteria in rice seeds after green manure rotation was significantly higher than that in winter fallow, and the community composition also changed significantly. At the genus level, Pseudomonas and Xanthomonas were the dominant genera in R - R - WF, accounting for 28.57% and 26.19% respectively, while Pantoea was the dominant genus in R - R - MV, accounting for 27.94%, followed by Pseudomonas (14.71%) and Paenibacillus (13.24%). Among the 31 strains for functional detection, most of the isolates had properties beneficial to plants, indicating that endophytic bacteria in seeds are closely related to the growth and health of plants. This study not only reveals that long-term rotation conditions can change the microbial composition of seeds, but also obtains beneficial microbial resources, which will contribute to the research and application of seed endophytes as bio-inoculants in sustainable agriculture.

：种子被视为有益微生物的储存库和载体。与根际和叶际相比，种子相关细菌的研究还十分落后。本研究.以长期绿肥植物与水稻轮作（稻- 稻- 紫云英，R-R-MV）和冬闲（稻- 稻- 冬闲，R-R-WF）两种种植模式的.水稻种子为材料，分离种子内生细菌；在对菌株进行16S rRNA 基因系统发育分析基础上，依据分离来源和分类地.位选择代表菌株，进行溶磷、产IAA 和铁载体等植物促生功能的检测。结果显示，绿肥轮作后水稻种子内生细菌.的数量显著高于冬闲，群落组成也发生了明显变化。在属水平上，Pseudomonas 和Xanthomonas 是R-R-WF 中的.优势属，分别占28.57％和26.19％，而R-R-MV 中Pantoea 是优势属，占27.94％，其次是Pseudomonas（14.71％）.和Paenibacillus（13.24％）。进行功能检测的31 个菌株中，大多数分离株具有有益于植物的特性，表明种子内生.细菌与植物的生长及健康密切相关。本研究不仅揭示了长期轮作条件可以改变种子的微生物组成，还获得了有益.的微生物资源，将有助于种子内生菌作为生物接种剂在可持续农业中的研究和应用。