秸秆还田对水稻根际微生物多样性和水稻纹枯病发生的影响

Effects of straw returning on microbial diversity in rice rhizosphere and occurrence of rice sheath blight

为探究稻麦轮作模式下秸秆还田对水稻根际微生物多样性与水稻纹枯病发生的影响,本研究采用Illumina测序技术结合生物信息学比较分析了秸秆还田与不还田处理的水稻根际微生物群落多样性差异,并采用实时荧光定量PCR(real-time fluorescent quantitative PCR,RT-qPCR)对这2种稻田土壤中水稻纹枯病菌Rhizoctonia solani含量进行测定,并采用随机五点取样法调查稻田中水稻纹枯病发病率和病情指数。结果表明,秸秆还田后水稻根际细菌群落Chao1丰富度指数和Shannon多样性指数均有所增加,分别增加14.42%和4.39%,其中前者增幅显著;根际真菌群落Chao1丰富度指数降低29.60%,而Shannon多样性指数略有增加,增加5.96%;在门水平上,秸秆还田和不还田处理的水稻根际土壤优势细菌门均为变形菌门、放线菌门、绿弯菌门和酸杆菌门,优势真菌门均为子囊菌门、接合菌门和担子菌门;在属水平上,秸秆还田处理的硝化螺旋菌属和芽胞杆菌属相对丰度分别比不还田处理的显著增加96.11%和106.19%;在水稻孕穗期秸秆还田土壤中水稻纹枯病菌含量比不还田处理的显著增加120.20%;秸秆还田后水稻纹枯病发生加重,病情指数比不还田处理的增加18.10%~45.41%。

To explore the effects of straw returning on microbial diversity in rice rhizosphere and occurrence of rice sheath blight,Illumina high-through sequencing technology combined with related bioinformatics analysis were used to analyze the difference in the rice rhizosphere community diversity between straw returning paddy field(SRPF)and none-straw returning paddy field(NSRPF),and real-time fluorescence quantitative PCR(RT-qPCR)was employed to investigate the Rhizoctonia solani content in paddy fields under a rice-wheat cropping system.The incidence rate and disease index of rice sheath blight in paddy fields were investigated via random five-point sampling.As a result,the Chao1 richness index and Shannon diversity index of bacterial community in rhizosphere of SRPF were higher than those of NSRPF,which increased by 14.42%and 4.39%,respectively,and the increase of richness was significant.The diversity of fungal community in rhizosphere soil of SRPF decreased by 29.60%compared to that of NSRPF,whereas the diversity was slightly increased by 5.96%.At the phylum level,Proteobacteria,Actinobacteria,Chloroflexi and Acidobacteria were found to be the dominant bacterial phyla in rhizosphere soils of both treatments,while Ascomycota,Zygomycota and Basidiomycota were the dominant fungi phyla.At genus level,the relative abundance of Nitrospira and Bacillus increased significantly by 96.11%and 106.19%,respectively,in SRPF,compared to of NSRPF.In comparison to NSRPF,the R.solani content increased in SRPF significantly by 120.20%during booting stage.In SRPF,the disease index of rice sheath blight increased by 18.10%-45.41%.