| 摘要: |
| 【目的】基于高通量技术和功能预测，探究水稻根际细菌群落主要生理代谢过程基因表达水平及其对高温胁迫的响应特征。【方法】通过盆栽试验对拔节期水稻进行7 d的高温胁迫处理，提取根际土壤微生物DNA进行高通量测序，结合PICRUSt功能预测进行细菌群落分析、基因注释及功能分类。【结果】与对照相比，高温胁迫促进了一些丰度相对较低的细菌门类（如：芽孢单菌门、浮霉菌门、Latescibacteria、螺旋菌门、Microgenomates和Candidatus_Berkelbacteria）的富集，提高了细菌多样性和细菌菌群之间共生关系的比例。细菌中活性基因主要源于变形菌门，其次是酸杆菌门、放线菌门和绿弯菌门。基于COG功能分类发现，对照与高温胁迫处理土壤中表达量最高的基因均为新陈代谢相关的基因，其次是参与细胞加工和信号传递的基因。但高温胁迫提高了参与细胞运动、信号传导机制、胞内运转、分泌和囊泡运输和细胞壁/膜/器形成基因的相对丰度；却降低了参与氨基酸运输和代谢、脂质转运和代谢、次生代谢生物合成以及翻译的相关基因的丰度。【结论】高温胁迫虽未改变根际细菌菌群结构，但提高了细菌群落多样性，加强了细菌菌群的共生关系，显著影响参与细胞的周转，代谢以及蛋白质合成的基因表达。 |
| 关键词: 高温胁迫；水稻；根际细菌；生理代谢；功能基因 |
| DOI：10.13522/j.cnki.ggps.2019160 |
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| The Effects of Thermal Stress on Diversity of Rhizobacteria and Functional Genes of Rice Rhizosphere |
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QIU Husen, ZHEN Bo, ZHOU Xinguo
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1. Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences, Xinxiang 453002, China;2. National Agro-ecological System Observation and Research Station of Shangqiu,Chinese Academy of Agricultural Sciences, Shangqiu 476000, China
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| Abstract: |
| 【Objective】Rice is able to withstand thermal stress to some extent by regulating its physiological and biochemical processes. Since change to the plant metabolic process alerts the quality of carbon input to soil, thermal stress could shift the structure and functions of microbial communities in the rhizosphere. These in turn will change nutrients supply and resistance of the plant against pathogeneses due to the change in functional genes of soil microbes. Understanding the response of metabolic functions of rhizosphere microbes to environmental stress is hence important to improve soil ecosystem services and biogeochemical cycles.【Objective】The purpose of this paper is to elucidate the responsive change in expression of functional genes associated with physiological metabolic processes of rhizobacteria to thermal stress using high-throughput technique and functional prediction.【Method】The experiment was conducted in pots grown with rice. Thermal stress was deliberately introduced to the plant for seven days at the jointing stage. The bacterial flora analysis, gene annotation and function classification were performed in conjunction with the PICRUSt (Phylogenetic Information of Common by Construction of States) and the high-throughput sequencing. 【Result】Compared with the control, thermal stress enriched the relatively low abundant bacterial classes (such as Gemmatimonadetes, Planctomycetes, Latescibacteria, Spirochaetae, Microgenomates, and Candidatus_Berkelbacteria); it also increased the numbers and percentage of the positive link (bacteria-bacteria) between taxa. Most transcripts of the bacteria were derived from Proteobacteria, followed by Acidobacteria, Actinobacteria, and chlorobi. Based on the COG functional classification database, the main active genes in both control and thermal stress treatments were associated with metabolism, cellular processes and the signaling. Thermal stress increased relative abundance of the genes associated with cell motility, signal transduction, intracellular trafficking, secretion, vesicular transport, and biogenesis of cellular wall, membrane and envelope. In contrast, it reduced the relative abundance of genes associated with amino acid transport and metabolism, lipid transport and metabolism, secondary metabolites biosynthesis, transport and catabolism, and transcription. Thermal stress did not affect rhizobacteria flora, but increased bacterial Shannon diversity, strengthened the symbiotic relationship of bacterial flora, and significantly impacted expression of genes involved in cell growth and death, as well metabolism and protein synthesis. 【Conclusion】Thermal stress not only affects physiology of rice but also alters the structure of the microbe community in the rhizosphere and the relative abundances of the function genes. |
| Key words: therma stress; rice; rhizobacteria; physiological metabolism; functional genes |
