健康香蕉（Musa paradisiaca）植株与枯萎病患病植株根区土壤细菌多样性的比较研究

摘要

Currently banana fusarium wilt (Fusarium oysporumf. cubense) is one of the important soil-borne diseases of seriously threat to banana production. However, there is no effective method for prevention in the world. The objective of this study was providing research information for the prevention of banana fusarium wilt from the perspective of microbial ecology. Two gene libraries of 16S rRNA were constructed by directly extracted from soil total DNA. And the soil samples were collected from root zone of banana which infected with fusarium wilt and non-infected plants in three typical plots infected by banana fusarium wilt (Jianfeng, Shiyuetian, Chongpo) in Hainan Province. The soil bacterial genetic diversity was analyzed by DNA sequencing and phylogenetic characters. The results were shown as follows: (1) the number of operational taxonomic units (OTUs) in soils from root zone of banana which infected with fusarium wilt was 18 lower than that of non-infected plants. The Shannon index (H') and calculated species richness (Schao1) in soils from root zone of banana which infected with fusarium wilt was respectively 0.66 and 26 lower than that of non-infected plants. (2) 63 OTUs were belonged to 9 bacterial taxa and 4 non-determined genotypes in soils from non-infected plants, and 45 OTUs were belonged to 8 bacterial taxa and 2 non-determined genotypes in soils from fusarium wilt infected plants. And the 6 bacterial phyla of Firmicutes, Proteobacteria, Actinobacteria, Acidobacteria, Gemmatimonadetes and Planctomycetes among them were common bacterial taxa in soils from root zone of banana both infected with fusarium wilt and non-infected plants. However, Cyanobacteria and Bacteria intertae sedis were only existed in the soils from root zone of banana plants which non-infected with fusarium wilt. In contrast, Nitrospia was only observed in the soils from root zone of infected plants. (3) The proportion of Firmicutes in soils from fusarium wilt infected plants was 11% higher than that of non-infected plants. Meanwhile, the increasing ofBacillus proportions in soils from fusarium wilt infected plants was also 15% higher than that of non-infected plants. These results indicated that the reducing of soil bacterial genetic diversity and its changing of community structure was important characteristics on occurrence of banana fusarium wilt, and increasing in the number ofBacillus in soil was the most important characteristics on occurrence of banana fusarium wilt.%香蕉枯萎病（Fusarium oysporum f. cubense）是当前严重威胁香蕉产业的重要土传病害，目前尚未找到有效的防治措施。本研究利用3个典型香蕉枯萎病患病样地的健康植株根区土壤（WB土）和患病植株根区土壤（FB土）分别直接提取土壤总DNA构建16S rRNA基因克隆文库，分析土壤细菌遗传基因多样性。旨在阐明香蕉枯萎病发病对植株根区土壤细菌多样性的影响，从微生物生态学的角度解释香蕉枯萎病的发生原因并为其防控提供理论依据。结果如下，（1）患病植株根区土壤细菌的基因型数（OTUs）比健康植株减少了18个，香农指数（H'）比健康植株降低了0.66，物种多样性指数（Schao1）比健康植株减少了26。（2）WB文库63个OTUs分属于9个细菌类群和4个尚未确定分类地位基因型，FB文库45个OTUs分属于8个细菌类群和2个尚未确定分类地位的基因型。其中厚壁菌（Firmicutes）、变形菌（Proteobacteria）、放线菌（Actinobacteria）、酸杆菌（Acidobacteria）、芽单胞菌（Gemmatimonadetes）和浮霉菌（Planctomycetes）6个门为健康和患病香蕉植株根区土壤中共有的细菌类群。此外，蓝细菌和Bacteria intertae sedis仅存在于WB土中，而硝化螺旋菌仅存在于FB土中。（3）香蕉枯萎病发病对厚壁菌数量分布的影响极大，FB土比WB土总体增加了11%。其中对芽孢杆菌（Bacillus）数量分布的影响极大，FB土中芽孢杆菌数量比WB土增加了15%。上述结果表明，香蕉植株根区土壤细菌遗传基因多样性降低及其群落结构改变是香蕉枯萎病患病的重要特征，其中芽孢杆菌（Bacillus）数量增加是香蕉枯萎病患病的最主要特征。