干旱胁迫对马铃薯全生育期根际土壤细菌群落的影响

Effects of drought stress on rhizosphere soil bacterial community of potato throughout the reproductive period

  • 摘要: 【目的】探讨干旱胁迫对马铃薯全生育期根际土壤细菌群落的影响,揭示马铃薯根际土壤细菌对干旱胁迫的响应机制,分析根际土壤环境因子与根际细菌群落的互作关系,为根际土壤细菌资源开发利用及提高马铃薯对干旱胁迫的适应性提供理论依据。【方法】以马铃薯品种丽薯6号为试验材料,采用盆栽控水试验,设干旱胁迫处理和正常浇水处理,通过16S rRNA进行高通量测序,分析马铃薯苗期、块茎形成期、淀粉积累期和成熟期的根际土壤细菌群落结构变化特征,并利用冗余分析和Mantel检验分析土壤环境因子与根际细菌群落的关系。【结果】不同生育时期干旱胁迫对土壤理化性质的影响不同。干旱胁迫对马铃薯根际土壤细菌种群在某一生育时期内获得的有效条带数、分类操作单元(OTU)数量及注释到的菌门、菌目、菌科和菌种数无显著影响(P>0.05,下同),但显著降低块茎形成期注释到的菌纲数(P<0.05,下同),显著增加淀粉积累期注释到的菌属数; α多样性分析结果表明,干旱胁迫处理的Simpson、Chao1和Shannon指数在马铃薯全生育期与正常浇水处理无显著差异,ACE指数在苗期、块茎形成期和成熟期均显著高于正常浇水处理,在淀粉积累期呈相反趋势;从相对丰度来看,干旱胁迫与正常浇水处理下马铃薯全生育期内根际土壤中的变形菌门(Proteobacteria)、酸杆菌门(Acidobacteriota)、放线菌门(Actinobacteriota)、芽单胞菌门(Gemmatimonadota)、绿弯菌门(Chloroflexi)、拟杆菌门(Bacteroidota)、粘球菌门(Myxococcota)为优势菌门;冗余分析和Mantel检验分析表明,土壤电导率、有机碳和pH是影响马铃薯根际土壤细菌群落组成的关键因子。【结论】干旱胁迫显著影响马铃薯全生育期内根际土壤细菌的相对丰度,提高马铃薯在苗期、块茎形成期和成熟期根际土壤细菌群落丰富性和均匀度。马铃薯根际土壤pH、电导率和有机碳含量是影响马铃薯根际土壤细菌群落结构的关键因子。

     

    Abstract: 【Objective】 To explore the effects of drought stress on rhizosphere soil bacterial community during the whole life cycle of potato,to reveal the response mechanism of potato rhizosphere soil bacteria to drought stress,and to analyze the interactions between rhizosphere soil nutrients and rhizosphere bacterial community,so as to provide theoretical basis for the development and utilization of rhizosphere soil bacterial resources and improvement of the structure of rhizosphere soil bacterial community through the regulation of soil nutrients and thus to improve the adaptability of potato to drought stress.【Method】 The potato variety Lishu 6 was used as the test material, and the drought treatment(D) and normal watering treatment(CK) were set up in a potted water control test, and 16S rRNA was used for high-throughput sequencing to analyze the structural changes of the rhizosphere soil bacterial community at the seedling, tuber formation, starch accumulation and maturity stages of potato. The relationships between soil environmental factors and rhizosphere bacterial communities were analyzed using redundancy analysis(RDA) and Mantel test.【Result】 Drought stress affects soil physico-chemical properties differently at different fertility periods,drought stress did not significantly affect the number of effective tags, OTUs and the number of annotated phyla, orders, families and species of potato rhizosphere soil bacterial populations during a given reproductive period(P>0.05,the same below), and that drought stress significantly reduced the number of annotated phyla during tuber formation(P<0.05,the same below),and significantly increased the number of annotated genera during starch accumulation compared with the control. α diversity analysis showed that the Simpson, Chao1 and Shannon indexes were not significantly different from the control during the whole growing period of potato compared to normal watering, while the ACE index was significantly higher than the normal watering group at the seedling, tuber formation and maturity stages, with an inverse trend at the starch accumulation stage. Proteobacteria, Acidobacteriota, Actinobacteriota, Gemmatimonadota, Chloroflexi, Bacteroidota and Myxococcota were the dominant phylum in the rhizosphere soil during the whole growing period under drought stress and normal watering treatment; RDA and Mantel test analysis showed that soil conductivity, organic carbon and pH were the key factors affecting the composition of soil bacterial communities in potato roots.【Conclusion】 Drought stress significantly affects the relative abundance of rhizosphere soil bacteria throughout the potato reproductive period, increases the abundance and evenness of rhizosphere soil bacterial communities at seedling, tuber formation and maturity stages. Potato rhizosphere soil pH, conductivity and organic carbon content are key factors affecting the structure of the potato rhizosphere soil bacterial community.

     

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