水稻种内间栽根际微生物群落对稻瘟病抗性的影响

Effects of the rhizosphere microbial community in interspecific intercropping of rice on the resistance against rice blast

  • 摘要: 【目的】揭示水稻种内混合间栽下根际土壤细菌群落与稻瘟病抗性的关系,为明确水稻多样性混合间栽控制稻瘟病的内在机理提供理论基础。【方法】以1个感稻瘟病传统品种黄壳糯(HKN)分别与4个云南主栽抗稻瘟病水稻品种汕优63(SY63)、Ⅱ优838(LY838)、两优1259(LY1259)、云光101(YG101)进行混合间栽及净栽。水稻长至黄熟期,采用五点取样法调查穗颈瘟发生情况;利用16S rDNA测序分析水稻多样性混合间栽根际土壤细菌群落多样性及组成变化。【结果】混合间栽后能有效减轻稻瘟病发生程度,不同组合下对感病品种黄壳糯的防治效果达42.14%~73.27%。水稻根际细菌群落多样性分析结果显示,混合间栽对水稻根际细菌群落Alpha多样性影响较小;主坐标分析结果显示,除HKN‖YG101组合中的黄壳糯在间栽前后根际细菌群落结构无显著改变(P>0.05)外,其他组合主栽品种和间栽品种在间栽前后根际细菌群落结构均出现显著变化(P<0.05,下同)。各处理优势细菌菌门为放线菌门(Actinobacteriota)、绿弯菌门(Chloroflexi)、厚壁菌门(Firmicutes)、变形菌门(Proteobacteria)和酸杆菌门(Acidobacteriota)。黄壳糯间栽后根际细菌相对丰度较高且发生显著变化的属有7种,其中慢生根瘤菌属(Bradyrhizobium)相对丰度与稻瘟病发病率和病情指数呈显著正相关,大理石雕菌属(Marmoricola)相对丰度与稻瘟病发病率和病情指数呈显著负相关。【结论】多样性混合间栽能明显改变水稻根际细菌群落结构,并通过富集大理石雕菌属提高感病品种稻瘟病抗性,从而减轻稻瘟病发病率。

     

    Abstract: 【Objective】The objective of this study was to reveal the relationship between rhizosphere soil bacterial community and rice blast resistance under rice interspecies mixed intercropping. This study provided theoretical basis for clarifying the internal mechanism of rice blast control under rice diverse mixed intercropping. 【Method】A traditional rice blast susceptible variety HKN and four modern rice blast resistant varieties SY63, LY838, LY1259 and YG101 were used to conduct mixed intercropping and monoculture. When the rice grew to the yellow maturity stage, the occurrence of rice neck blast was investigated by the five-point sampling method. The diversity and composition changes of soil bacterial communities in the rhizosphere of rice diverse mixed intercropping were analyzed by 16S rDNA sequencing. 【Result】Mixed intercropping treatment could effectively reduce the occurrence of rice blast, and the control effect of HKN(susceptible variety) under different combinations reached 42.14%-73.27%. The results of rice rhizosphere bacterial community diversity showed that mixed intercropping had slight effects on the Alpha diversity of rice rhizosphere bacterial community. The results of principal coordinate analysis showed that except that the rhizosphere bacterial community structure in the HKN‖YG101 combination had no significant change in the rhizosphere bacterial community structure before and after intercroppting(P>0.05), and the rhizosphere bacterial community structure of the other main varieties and intercropped varieties showed significant changes before and after intercropping(P<0.05, the same below). The dominant bacterial phyla were Actinobacteriota, Chloroflexi, Firmicutes, Proteobacteria and Acidobacteriota. There were 7 genus with high relative abundance in the rhizosphere and significant changes after HKN intercropping, among which relative abundance of Bradyrhizobium was significantly and positively correlated with the incidence and disease index of rice blast, the relative abundance of Marmoricola was significantly and negatively correlated with the incidence and disease index of rice blast. 【Conclusion】Diverse mixed intercropping can greatly change the rice rhizosphere bacterial community structure and reduce the occurrence of rice blast by enriching Marmoricola and increasing the resistance of susceptible varieties to rice blast.

     

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