马铃薯全生育期内根际微生物组变化规律

Community rhythms of rhizosphere microbiome during the whole life cycle of potato

摘要:

[目的]陆生植物根际环境与土壤中的微生物菌群关系密切，其根际微生物群落动态极可能直接影响着植物健康及养分高效利用。虽然根际益生菌已被证实可用于提高作物生产力，但由于缺乏对这些菌群组成动态变化规律的认识了解，它们的开发受到限制。研究马铃薯全生育期根际菌群的动态变化规律，探讨根际菌群变化与马铃薯发育时期的相关性，为针对马铃薯不同生长时期开发专用生物益生菌肥奠定理论基础。[方法]本研究着眼于马铃薯田间全生命周期微生物组动态变化，通过Illumina MiSeq高通量测序技术对不同时间点马铃薯根际细菌16SrRNA基因V3-V4区和真菌ITS区测序并对操作分类单位（OTU）进行聚类，分析样品间微生物群落的多样性特征，并通过机器学习的方法建立模型，将根际菌群与田间马铃薯发育时间相关联。[结果]根际菌群在马铃薯各个发育阶段随时间变化明显，营养生长阶段的微生物群落结构发生了显著变化，随着结薯期的开始逐渐稳定，直到块茎成熟后期根际菌群再次出现较大变化，且在不同施肥处理间呈现较大差异。进一步基于模型挖掘了与马铃薯发育时间相关联的22个特征细菌类群和16个特征真菌类群，其中苗期和结薯末期的特征类群分别为梭菌（Clostridium）和放线菌（Actinobacteria）。[结论]马铃薯的生长发育时期是影响根际微生物群落组成的主要因素，益生菌肥的添加主要影响马铃薯结薯末期的细菌微生物菌群结构。

关键词:马铃薯;根际微生物组;生育期标记;群落动态

Abstract:

[Objective] The rhizosphere environment of terrestrial plants is closely related to the microbe in the soil. Accumulating evidences indicate that dynamics of rhizosphere microbial community directly affect plant health and nutrients utilization. Although rhizosphere microbes are useful for increasing crop productivity, their development has been limited due to a lack of understanding of the dynamics of microbiome. The dynamic changes of rhizosphere microbiome in the whole growth period of potato were studied, and the correlation between rhizosphere biomarkers and potato developmental stage was discussed here. This study will lay foundation for the development of special bio-probiotic fertilizer for different developmental stages of potatoes.[Methods] This study focused on the microbial dynamics of the whole life cycle of potato in field. The Illumina MiSeq high-throughput sequencing technology was used to sequence the 16S rRNA gene V3-V4 region and the fungal ITS region of potato rhizosphere microbe at different time points and to classify the OTUs, in order to analyze the diversity characteristics of microbial communities between samples, and we also established a model through machine learning to correlate rhizosphere microbes with potato development stages in the field. [Results] The rhizosphere microbiome changed significantly with developmental stages. The microbial community structure in the vegetative growth stage changed significantly and it gradually stabilized at beginning of the reproductive stage, and the rhizosphere microbiome varied a lot in the late stage of tuber maturity. In addition, 22 bacterial biomarkers and 16 fungal biomarkers associated with potato development stages were identified based on the model, which are the biomarker Clostridium in seedling stage and Actinobacteria in tuber matured stage. [Conclusion] The growth and development period of potato is the main factor affecting the composition of rhizosphere microbial community. The addition of probiotic fertilizer has a certain effect on maintaining and stabilizing the rhizosphere bacterial community in the late development stage.

Key words:potato;rhizosphere microbe;microbial diversity;rhizosphere microbiome;biomarkers;community dynamics