肉苁蓉内生细菌多样性及功能菌株的分离筛选

Diversity of endophytic bacteria and screening of functional strains from Cistanche deserticola

【背景】植物内生菌是研究微生物多样性和适应性进化的宝库。肉苁蓉(Cistanche deserticola)是列当科的药用植物之一,有“沙漠人参”的美誉,具有极高的药用价值。然而有关肉苁蓉内生菌的相关研究较为有限。【目的】解析不同种类肉苁蓉内生细菌群落多样性差异,并挖掘相关内生细菌资源。【方法】利用高通量测序技术,对管花肉苁蓉(GH)和荒漠肉苁蓉(HM)群落组成差异及多样性进行分析;采用传统微生物分离方法开展相关内生细菌分离培养,利用16S rRNA基因序列比对初步明确菌株的分类定位,进一步测定菌株的抗逆、促生及抑菌特性。【结果】高通量测序结果表明,GH和HM共获得内生菌OTU 1086个,其中共有OTU为46个,仅占总数的4.24%;所获得的内生细菌OTU共涉及19个门104个目226个属及一些未分类的细菌,变形菌门(Proteobacteria)为共同的优势菌门,占69.46%,但两种肉苁蓉样品之间内生细菌群落结构存在明显差异。实验分离获得65株肉苁蓉内生细菌,归属于芽孢杆菌门(Bacillota)、变形菌门(Proteobacteria)和放线菌门(Actinomycetota)等3个门20个属34个种,其中芽孢杆菌门(Bacillota)占比最高,并分离筛选多株抗逆、促生及抑菌菌株。【结论】管花肉苁蓉(GH)和荒漠肉苁蓉(HM)微生物群落组成存在明显差异,实验获得一批肉苁蓉内生细菌菌株,为进一步开发利用肉苁蓉内生菌提供了前期基础。

[Background]Plant endophytes represent the treasure for investigating microbial diversity and adaptive evolution.Cistanche is a genus of medicinal plants belonging to Orobanchaceae and honored as“ginseng of the deserts”.However,few studies have been carried out on the endophytes of Cistanche.[Objective]To investigate the diversity of endophytic bacteria in different Cistanche species and explore the endophytic bacterial resources.[Methods]The plants of Cistanche tubulosa(Schrenk)R.Wight(GH)and C.deserticola Y.C.Ma(HM)were sampled and subjected to high-throughput sequencing.The conventional microbial isolation method was used to isolate endophytic bacteria,and the isolates were identified by 16S rRNA gene sequence alignments.Subsequently,the stress tolerance,plant growth-promoting effects,and antimicrobial activities of the strains were evaluated.[Results]The high-throughput sequencing revealed a total of 1086 OTUs of endophytic bacteria in GH and HM samples,among which 46(4.24%)common OTUs were shared by the two species.The OTUs belonged to 226 genera,104 orders of 19 phyla and some uncategorized bacteria.Proteobacteria was the dominant phylum in both samples,accounting for 69.46%.Significant differences were observed in the community structure of endophytic bacteria between the two species.In addition,65 strains of endophytic bacteria were isolated from the plants,belonging to 34 species,20 genera of 3 phyla(Bacillota,Proteobacteria,and Actinomycetota),and Bacillota had the highest relative abundance.Furthermore,the stress tolerance,plant growth-promoting effects,and antimicrobial activities of the isolates were evaluated.[Conclusion]The community structure of endophytic bacteria presented significant differences between Cistanche species.This study isolated several endophytic bacterial strains,which provided a basis for subsequent applications.