健康与罹患青枯病的番茄土壤细菌群落特征比较

应用实时荧光定量PCR及MiSeq高通量测序技术,全面地研究了连作番茄田块中健康与感染青枯病植株周围土体及根际土壤细菌群落结构和组成。结果表明:健康番茄土体土壤的pH及全碳含量显著高于感病番茄土体土壤;土体及根际土壤的细菌群落结构和组成明显不同于感病番茄土体及根际土壤细菌群落。与感病番茄根际相比,健康番茄根际细菌的数量显著升高而青枯菌数量显著降低;细菌群落的Shannon多样性指数显著增高;拟杆菌门及其所含的噬几丁质菌属、金杆菌属、动杆菌属、黄杆菌属及Taibaiella的相对丰度显著增高而变形菌门及其所含的青枯菌属的相对丰度显著降低。综上,抑制土传青枯病发生的番茄根际土壤细菌群落特征明显,其生物量及多样性高,土著有益菌群数量多而病原菌数量少,为番茄土传青枯病的生物防控提供了指导方向与理论依据。

Comparison of Bacterial Communities in Bulk and Rhizosphere Soils of Healthy and Diseased Tomato Infected by Bacterial Wilt

The global tomato production is severely hindered by bacterial wilt disease which is caused by the invasion of Ralstonia solanacearum. The soil microbial composition and function is tightly linked to plant health, thereby it is very important to decipher the characteristic of microbiome in soils from healthy and diseased tomato plants infected by soil-borne wilt disease. In present study, real time PCR and MiSeq sequencing technology was used to deeply compare the differences of bacterial community structure and composition in bulk and rhizosphere soil collected from healthy and diseased tomato plants under mono-cropping system. The results showed that bulk soil sampled from healthy tomato plants displayed a higher pH value and total carbon content. The bacterial structure and composition in bulk and rhizosphere soil sampled from healthy tomato plants was obviously different from that sampled from diseased tomato plants. Compared to diseased rhizosphere, rhizosphere soil sampled from healthy tomato plants exhibited a significant higher number of total bacteria and a significant lower number of R. solanacearum. Also, rhizosphere soil sampled from healthy tomato plants showed a significant higher index of Shannon diversity. Furthermore, the relative abundance of Bacteroides and Chitinophaga, Chryseobacterium, Dyadobacter, Flavobacterium and Taibaiella included in Bacteroides was significantly enriched while the relative abundance of Proteobacteria and Ralstonia included in Proteobacteria was significantly depleted in rhizosphere soil collected from healthy tomato plants compared to that collected from diseases tomato plants. In summary, soil suppressive to tomato bacterial wilt disease harbored a unique bacterial community, which showed a high bacteria population size, diversity, and a high relative abundance of beneficial indigenous microorganisms and low relative abundance of pathogen. This research could provide a guideline and theoretical principle for biological control of tomato bacterial wilt disease.