盐胁迫对白及根际细菌群落组成及多样性的影响

Effects of salt stress on bacterial community composition and diversity in rhizosphere soil of Bletilla striata

盐渍化环境不仅会影响植物正常的生长发育,还会对植物根际微生物群落产生影响。为探究盐胁迫条件下白及根际土壤细菌群落的演替模式,采用细菌16S rRNA高通量测序技术测定不同盐胁迫浓度下白及根际土壤细菌群落组成及多样性,分析盐胁迫对白及植株生长发育和土壤理化性质的影响以及白及根际菌群组成与土壤因子间的相关关系。结果表明:与对照相比,盐胁迫环境使白及植株生长速度和长势下降,土壤中有机质、氮、磷含量显著降低。盐胁迫处理后白及根际土壤细菌物种多样性和均一度呈现先下降后升高的变化趋势。在门和纲水平上白及根际土壤细菌优势类群的相对丰度和变化趋势在对照与盐胁迫处理间差异显著。盐胁迫浓度和胁迫时间均显著影响白及根际土壤细菌群落组成;土壤有机质、速效氮和总磷含量是影响根际细菌群落结构的关键环境因子。与细胞骨架、细胞运动、物质代谢及信号转导机制相关的功能基因可能参与了菌群对盐胁迫的适应及应答。本研究将为盐渍地区白及的栽培管理提供理论基础和参考依据。

Salinization environment affects the normal growth and development of plants,as well as the microbial community in the rhizosphere.To explore the succession dynamics of bacterial communities in the rhizosphere soil of Bletilla striata under salt stress condition,we performed 16S rRNA high-throughput sequencing to determine the bacterial community composition and diversity of B.striata in the rhizosphere under different salt stress concentrations,measured the effects of salt stress on the growth and development of B.striata and soil physicochemical properties,and analyzed the correlation between community composition of rhizosphere bacteria and the soil environmental factors.The results showed that compared with the control,salt stress reduced growth rate and health degree of B.striata,and significantly decreased the content of soil organic matter,nitrogen and phosphorus.Under the salt stress treatment,species diversity and evenness of the bacterial communities in the rhizosphere of B.striata showed a trend of first decreasing and then increasing.There were significant differences in the relative abundance and variation trends of the dominant bacterial taxa in the rhizosphere soil of B.striata at the phylum and class levels between the control and the salt stress treatments.Salt stress intensity and duration were important factors affecting bacterial community composition in the rhizosphere soil of B.striata.Soil organic matter,available nitrogen,and total phosphorus content were key environmental factors affecting the structure of rhizosphere bacterial community composition.Functional genes related to cytoskeleton,cell motility,substance metabolism and signal transduction mechanisms may be involved in the adaptation and stress response of bacterial communities to salt stress.This study would provide theoretical basis and reference for the cultivation management of B.striatain saline area.