施用石灰氮对烟株根际土壤微生物区系的影响

Effect of lime nitrogen application on microbial flora of tobacco rhizosphere soil

为研究施用石灰氮对烟株根际土壤微生物区系变化及其对烟草青枯病发病率的影响,分别在烟株不同生长期采集根部土壤进行16S/18S rDNA基因测序,以分析烟株生长过程中微生物数量、多样性以及群落结构的变化。结果表明,施用石灰氮后,在烟株生长的团棵期硝化螺旋菌门(Nitrospirae)、担子菌门(Basidiomycota)相对丰度相比对照分别增加了55.0%和105.6%,子囊菌门(Ascomycota)降低了20.2%,旺长期细菌的Sobs指数、Shannon指数和Chao指数分别增加了6.3%、3.1%和3.4%。PCA分析显示,施用石灰氮的处理与对照的根际土壤微生物区系结构从团棵期开始表现出差别,且随烟株生长差异逐渐增大。物种差异分析显示施用石灰氮的处理中鞘脂单胞菌属(Sphingomonas)、硝化螺旋菌属(Nitrospira)、黄杆菌属(Flavisolibacte)等与土壤氮循环有关的功能菌丰度显著增多。成熟期对青枯病发病率和烟叶产量等统计表明,施用石灰氮处理对烟草青枯病的防控率达到了49.9%,烟叶产量提高了11.7%。

To study the effect of lime nitrogen application on rhizosphere soil microflora of tobacco plant and its incidence of tobacco bacterial wilt,root soil was collected for 16 S/18 S rDNA gene sequencing at different growing stages of tobacco plants to analyze the changes of microbial quantity,diversity and community structure during the growth of tobacco plants.Results showed that after the application of lime nitrogen,in the rosette stage of tobacco plant growth,the relative abundance of Nitrospirae and Basidiomycota increased by 55.0%and 105.6%,respectively,and the Ascomycota decreased by 20.2%,the most vigorous bacteria Sobs index,Shannon index and Chao index increased by 6.3%,3.1%and 3.4%,respectively.PCA analysis showed that the microbial flora structure of rhizosphere soil treated with lime nitrogen was different from that of the control group from the beginning of the rosette stage,and the difference gradually increased with the growth of tobacco plants.The analysis of species differences showed that the abundance of functional bacteria related to soil nitrogen cycle,such as Sphingomonas,Nitrospira,Flavisolibacte,etc.,was significantly increased in the treatment with lime nitrogen.Statistics on the incidence of bacterial wilt and tobacco yield in the mature period showed that the control rate of lime nitrogen treatment on tobacco bacterial wilt reached 49.9%and the tobacco yield increased by 11.7%.