重庆烟区“K326”烟草品种靶斑病发生的叶际微生态因子分析

Analysis of the Microecological Factors of Target Leaf Spot of Tobacco Variety‘K326’in Chongqing Tobacco Area

为明确烟草靶斑病在重庆烟区“K326”烟草品种上对叶际微生物群落结构的影响,在重庆市酉阳县分别采集移栽40 d、60 d、80 d和100 d后具有烟草靶斑病与健康的烟叶样品,采用高通量测序方法分析样品中细菌群落结构,并结合烟株生长期气象因子和病害发生情况进行分析.移栽后40 d靶斑病开始发生,且发病率和病情指数呈上升趋势,移栽后60~80 d为发病高峰期.发病叶中叶际细菌优势菌门为变形菌门和厚壁菌门,优势菌属为假单胞菌属、微小杆菌属等.健康叶叶际细菌的优势菌门分别为蓝藻门、放线菌门、拟杆菌门等,优势菌属为不动杆菌属、微小杆菌属、芽孢杆菌属、泛细菌属等.健康叶的整体群落丰度大于发病叶,移栽40 d、60 d和100 d后采集样品的发病叶与健康叶叶际细菌群落结构比较差异具有统计学意义.靶斑病发生较重情况下,发病叶与健康叶叶际细菌群落结构上差异具有统计学意义,提示靶斑病的发生影响了叶际细菌群落结构.

In order to determine the key factors and microbial structure of the leaf microenvironment of tobacco target spot disease in‘K326’tobacco variety in Chongqing tobacco region,‘K326’tobacco variety was taken as experimental materials.Samples of diseased and healthy leaves of tobacco plants were collected in Youyang County,Chongqing at 40 d,60 d,80 d and 100 d after transplanting.The bacterial community structure in the leaves was analyzed by high-throughput sequencing method,and the climatic factors and disease occurrence during the growth period of tobacco plants were analyzed.At 40 days after transplantation,the onset of target spot disease was observed,exhibiting an upward trend in both disease incidence and severity index,and the period between 60 and 80 days after transplantation was identified as the peak phase of disease incidence.The dominant bacteria in the diseased leaf boundary were Proteobacteria and Thick-walled Bacteria.The dominant bacteria were Panbacterial,Pseudomonas,Microbacterium,etc.The dominant phyla of the healthy leaf boundary bacteria were:Thickwallida,Cyanophyta,Actinomyceta,Bacteroides,etc.The dominant genera were Pseudomonas,Acinetobacter,Microbacterium,Bacillus,Pantobacterium etc.The overall community richness of healthy leaves was greater than that of diseased leaves.The bacterial community structure of diseased leaves and healthy leaves collected on the 40,60 and 100 days after transplanting was significant different.In the case of severe target spot disease,there were significant differences in the bacterial community structure between the diseased leaves and the healthy leaves.