蛇足石杉内生细菌的分离鉴定及其促生特性

Isolation, identification, and plant growth-promoting effect characterization of endophytic bacteria from Huperzia serrata

摘要:

【背景】从植物中分离得到的内生细菌能产生多种多样的活性物质，能够促进宿主植物的生长发育，而目前对于珍稀野生药用植物蛇足石杉内生细菌分离及其促生功能的研究鲜见报道。【目的】从蛇足石杉中分离内生细菌并进行鉴定，从中筛选出具有多种促生功能的菌株，为蛇足石杉内生菌资源的开发利用提供参考。【方法】通过使用不同培养基对蛇足石杉不同组织部位的内生细菌进行分离，再根据菌落形态特征及16S rRNA基因序列测序比对进行菌种鉴定及系统发育分析，最后对菌株的固氮、溶磷、产铁载体、产吲哚乙酸(indole-3-acetic acid, IAA)这4种促生功能进行检测。【结果】从蛇足石杉根、茎、叶3种组织中共分离得到168株内生细菌，在分类学上归属于3门4纲5目6科16属，其中芽孢杆菌属(Bacillus)占55.95%，类芽孢杆菌属(Paenibacillus)占19.05%，为优势菌属；不同组织分离出的内生细菌数量与种类均有明显差异，表现为根部>茎部>叶部；从分离的内生细菌中筛选出95株具有固氮能力，76株具有溶磷能力，23株具有产铁载体能力，81株具有产IAA能力。【结论】从蛇足石杉分离的内生细菌具有丰富的物种多样性和促生功能，分布具有明显的组织特异性，并获得多株具有良好促生功能的菌株，为进一步开发菌肥资源提供了新的菌株材料，同时为进一步开发利用蛇足石杉内生菌资源奠定了基础。

Abstract:

[Background] Endophytic bacteria isolated from plants can produce a variety of active substances, which can promote the growth and development of host plants. However, there are few reports on the isolation and plant growth-promoting effects of endophytic bacteria from the rare wild medicinal plant Huperzia serrata. [Objective] To isolate and identify the endophytic bacteria from H. serrata, and screen out the strains with a variety of plant growth-promoting effects, thus providing a reference for the development and utilization of the endophytic bacterial resources of this plant. [Methods] The endophytic bacteria from different tissue samples of H. serrata were isolated by different media, and then the strain identification and phylogenetic analysis were carried out according to the colony morphological characteristics and 16S rRNA sequence alignment. Finally, the plant growth-promoting effects of the strains, including nitrogen fixation, phosphorus solubilization, siderophore production, and indole-3-acetic acid (IAA) production, were measured. [Results] A total of 168 strains of endophytic bacteria were isolated from the roots, stems, and leaves of H. serrata, belonging to 16 genera, 6 families, 5 orders, 4 classes of 3 phyla. Bacillus (strains accounting for 55.95%) and Paenibacillus (19.05%) were the dominant genera. The number and species of endophytic bacteria isolated from different tissue samples were significantly different, following the trend of root>stem>leaf. Among the 168 strains, 95, 76, 23, and 81 strains were capable of fixing nitrogen, solubilizing phosphorus, producing siderophores, and producing IAA, respectively. [Conclusion] The endophytic bacteria isolated from H. serrata have high diversity and can promote plant growth, and their distribution presents obvious tissue specificity. A number of strains with excellent plant growth-promoting effects have been obtained, providing new strain materials for the development of microbial fertilizers and laying a foundation for the development and utilization of endophytic bacterial resources of H. serrata.