不同耕作方式结合秸秆还田对玉米内生细菌多样性的影响

Effects of different patterns of tillage combined with straw returning on endophytic bacterial diversity in maize

摘要:

【目的】研究土默川平原不同耕作方式与秸秆还田模式下玉米内生细菌群落组成及功能，揭示不同耕作与秸秆还田方式促进玉米秸秆降解的内生菌资源，并为其选择性分离培养及其功能验证奠定基础。【方法】以内蒙古自治区土默川平原灌区连作玉米茎秆为研究对象，利用Illumina Miseq高通量测序技术，分析不同耕作及其秸秆还田方式连年定位试验条件下，玉米成熟期内生微生物多样性及群落结构差异。【结果】综合分析表明，免耕及深翻对玉米内生细菌群落多样性影响显著。不同耕作方式对玉米内生细菌群落组成结构的影响大于秸秆还田，玉米内生细菌群落结构首先可分为2类，第一类是免耕及其秸秆还田，第二类是其他7种耕作方式。从属水平来看，9种耕作方式共有的优势菌群分别为假单胞菌属(Pseudomonas)、肠杆菌科未分类属(unclassified_f__ Enterobacteriaceae)、泛菌属(Pantoea)、拉乌尔菌属(Raoultella)、拉恩氏菌属(Rahnella1)，秸秆还田可增加拉乌尔菌属及肠杆菌科未分类属的丰度。【结论】不同耕作方式改变了玉米内生细菌多样性、群落组成和结构；秸秆还田处理能够增加玉米茎秆中对秸秆降解有积极作用的拉乌尔菌属及乳球菌属(Lactococcus)的相对丰度。

Abstract:

[Objective] To reveal the composition and functions of endophytic bacterial communities in maize under different patterns of tillage combined with straw returning in the Tumochuan Plain, identify the endophytic bacterial resources that promote maize straw degradation under different patterns, and lay a foundation for the selective isolation, cultivation, and functional verification. [Methods] We employed Illumina MiSeq high-throughput sequencing to compare the diversity and community structure of endophytes during the mature stage of maize under different patterns of tillage combined with straw returning in the continuous positioning experiment in the irrigation area of Tumochuan Plain, Inner Mongolia Autonomous Region. [Results] No tillage and deep tillage demonstrated significant effects on the endophytic bacterial diversity of maize. Tillage methods exerted stronger effects on the composition and structure of endophytic bacterial community than straw returning. The structures of endophytic bacterial communities in maize can be classified into two categories: no tillage combined with straw returning and the other seven patterns. The dominant endophytic bacterial genera shared by the nine patterns of tillage combined with straw returning were Pseudomonas, unclassified_f__Enterobacteriaceae, Pantoea, Raoultella, and Rahnella1. Straw returning increased the abundance of Raoultella and unclassified_f__ Enterobacteriaceae. [Conclusion] Different tillage practices alter the diversity, composition, and structure of endophytic bacterial community in maize. Straw returning can increase the relative abundance of Raoultella and Lactococcus, which have positive effects on the degradation of maize straw.