陆均松和青梅根系细菌群落多样性特征及其影响因素

Diversity Characteristics and Influencing Factors of Root Bacterial Community of Dacrydium pectinatum and Vatica mangachapoi

为进一步探究根系细菌群落结构与环境因子的关系,本研究基于不同生态位,以海南岛2种热带雨林典型植物陆均松和青梅的根系为研究对象,利用Illumina Miseq高通量测序技术对细菌群落结构、多样性及功能进行分析。结果表明:1)陆均松和青梅根系细菌群落α多样性受到生态位的显著影响,根际和根表分别与根内细菌群落的α多样性指数存在极显著差异,并且α多样性沿根际-根表-根内生层的顺序呈下降趋势。2)根系细菌群落结构在不同生态位存在显著差异,生态位解释了根系细菌群落组成差异的14.7%,而植物种类解释了11.6%。在门水平上,相对丰度最高的前5个门依次为变形菌门、放线菌门、酸杆菌门、浮霉菌门和疣微菌门。热酸菌属、norank_f__Xanthobacteraceae、分枝杆菌属及Acidibacter、norank_f__norank_o__Elsterales是根系细菌群落的主要优势菌属。3)功能分析表明,细菌群落的一些功能群在根系不同生态位间存在显著差异,根表菌群富集大量功能群(化能异养、好氧化能异养等)。4)根系不同生态位细菌群落与不同的环境因子存在显著相关关系。驱动陆均松和青梅细菌结构差异的环境因子主要是温度和土壤pH。与树种相比,生态位对根系细菌群落结构有更强的影响,土壤pH、TK分别是影响根系细菌群落结构和多样性最重要的环境因子。研究结果为促进热带雨林濒危树种陆均松和青梅生长发育及其生态保护提供了科学依据。

The objectives of this study were to further explore the relationship between root bacterial community structure and environmental factors.Based on different niches,the structure,diversity and function of bacterial community were analyzed by Illumina Miseq high-throughput sequencing technique and by using the the roots of D.pectinatum and V.mangachapoi,two typical tropical rain forest plants occurring in Hainan Island.The results showed that 1)theαdiversity of bacterial community in the root system of D.pectinatum and V.mangachapoi was significantly affected by niche,and theαdiversity index of bacterial community in rhizosphere and rhizoplane was significantly different from that of endosphere,andαdiversity decreased along the order of rhizosphere,rhizoplane and endosphere.2)There were significant differences in root bacterial community structure in different niches.Niche explained 14.7%of the difference in root bacterial community composition,while plant species explained 11.6%.At phylum level,the first five phylums with the highest relative abundance were Proteobacteria,Actinobacteriota,Acidobacteriota,Planctomycetota and Verrucomicrobiota.The main dominant bacteria in the root bacterial community were Acidothermus,norank_f__Xanthobacteracea,Mycobacterium and Acidibacter,norank_f__norank_o__Elsterales.3)The functional analysis showed that some functional groups of bacterial community were significantly different among different root niches,and rhizoplane enriched a large number of functional groups(chemoheterotrophy,aerobic_chemoheterotrophy,etc.).4)There was a significant correlation of bacterial communities between different root niches and different environmental factors.The main environmental factors driving the difference of bacterial structure between D.pectinatum and V.mangachapoi were temperature and soil pH.Compared with tree species,niche has a stronger effect on root bacterial community structure.Soil pH and TK(total potassium)were the most important environmental factors affecting root bacterial community structure and diversity,respectively.The results of this study provide a scientific basis for promoting the growth,development and ecological protection of endangered tree species D.pectinatum and V.mangachapoi in tropical rain forest.