农田土壤根际微生物群落多样性特征研究

Study on Diversity Characteristics of Microbial Community in Rhizosphere Soil of Farmland

以藜麦、蚕豆、油菜和马铃薯为供试材料,设置连作藜麦(HLMA)和藜麦轮作马铃薯(HLMLS)、油菜(HLYC)、蚕豆(HLCD)4种不同种植模式,通过测定土壤养分含量,并利用高通量测序技术(Illumina-HiSeq)对4种种植模式下藜麦根际土壤的基因组进行测序,研究不同种植模式对作物土壤养分和细菌群落组成特征的影响。结果表明:3种轮作种植模式下全钾、碱解氮、速效磷、速效钾含量和pH较连作种植模式显著下降。HLCD模式提高土壤细菌群落丰富度指数、多样性指数和优势度指数。细菌组成研究结果显示,4种种植模式下占优势的细菌均为放线菌门(Actinobacteria)、变形菌门(Proteobacteria)、酸杆菌门(Acidobacteria)、绿弯菌门(Chloroflexi)、拟杆菌门(Bacteroidetes)和芽单胞菌门(Gemmatimonadetes)。HLCD处理下,放线菌门(Actinobacteria)、酸杆菌门(Acidobacteria)、绿弯菌门(Chloroflexi)、拟杆菌门(Bacteroidetes)和芽单胞菌门(Gemmatimonadetes)相对丰度均显著高于其他处理,分别达到50.48%、13.17%、11.90%、7.42%和4.50%,较HLMA处理分别增加44.21%、56.36%、36.19%、224.24%和53.16%。土壤细菌群落优势属以Subgroup、芽球菌属(Blastococcus)、67-14和土壤红杆菌属(Solirubrobacter)为主,但不同种植模式所占土壤各细菌属的相对丰度大小存在差异。HLCD处理下,Subgroup、芽球菌属(Blastococcus)、67-14和土壤红杆菌属(Solirubrobacter)相对丰度均显著高于其他处理,分别达到7.08%、5.48%、4.35%和3.49%,较HLMA处理分别增加51.99%、64.86%、49.89%和71.85%。聚类分析显示HLYC和HLMLS的组成最接近,其次是HLCD,HLMA的组成与前两者相差较大。土壤全钾、有效氮和速效磷是土壤细菌群落优势菌门变化的驱动因素。综上所述,连作藜麦后轮作蚕豆、油菜和马铃薯可改善土壤肥力,提高细菌群落组成丰富度。

In this study,quinoa,faba bean,rape,and potato were used as tested materials,and continuous cropping of quinoa(HLMA),and quinoa rotated with potato(HLMLS),rapeseed(HLYC),and faba bean(HLCD)were set as treatments.Characteristics of soil nutrients and bacterial community composition under these four quinoa planting patterns were determined by measurement of the soil nutrient content and use of high-throughput sequencing technology(Illumina-HiSeq)to sequence the rhizosphere soil genome of quinoa.Soil nutrient content and pH value decreased significantly with rotation compared with the continuous cropping pattern.Faba bean rotation increased the richness index,diversity index,and dominance index of the bacterial community in soil.For bacterial composition,the dominant bacterial phyla under the four cropping patterns were Actinobacteria,Proteobacteria,Acidobacteria,Chloroflexi,Bacteroidetes,and Gemmatimonadetes.Under HLCD treatment,the relative abundances of Actinobacteria,Acidobacteria,Chloroflexi,Bacteroidetes,and Gemmatimonadetes were significantly higher than those under other treatments,which respectively reached 50.48%,13.17%,11.90%,7.42%,and 4.50%,increased by 44.21%,56.36%,36.19%,224.24%,and 53.16% compared with HLMA treatment.The dominant genera of the soil bacteria were Subgroup,Blastococcus,67-14,and Solirubrobacter,but the relative abundances of soil bacterial genera differed under different planting patterns.Under HLCD treatment,the relative abundances of Subgroup,Blastococcus,67-14,and Solirubrobacter were significantly higher than those under other treatments,reaching 7.08%,5.48%,4.35%,and 3.49%,respectively.Compared with HLMA treatment,abundances increased by 51.99%,64.86%,49.89%,and 71.85%,respectively.The cluster analysis showed that the compositions of HLYC and HLMLS were the most similar,followed by HLCD,and the composition of HLMA was significantly different from the HLYC and HLMLS.Soil total potassium,available nitrogen,and available phosphorus were the driving factors for changes of the dominant phyla in the soil bacterial community.In conclusion,continuous cropping of quinoa followed by rotation of faba bean,rape,or potato can improve soil fertility and increase the richness of the bacterial community.