Ministry of Education Key Laboratory for Ecology of Tropical Islands, College of Life Sciences, Hainan Normal University, Haikou, 571158, China.
Guangdong Laboratory for Lingnan Modern Agriculture, Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Agriculture, South China Agricultural University, Guangzhou, 510642, China.
BMC Microbiol. 2020 Apr 14;20(1):89. doi: 10.1186/s12866-020-01774-y.
Ralstonia solanacearum is one of the most notorious soil-borne phytopathogens. It causes a severe wilt disease with deadly effects on many economically important crops. The microbita of disease-suppressive soils are thought that they can contribute to the disease resistance of crop plants, thus, evaluation of the microbial community and their interaction characteristics between suppressive soil (SS) and conducive soil (CS) will help to understand resistance mechanism. To do this, the bacterial community structure, correlation analysis with soil chemical properties, interaction network of SS (nearly no disease in three years), and CS (suffered heavy bacterial wilt disease) were analyzed.
A higher bacterial community diversity index was found in SS, the relative abundance of Nocardioides, Gaiella and norank_f_Anaerolineaceae were significantly more than that of the CS. Moreover, the relative abundance of main genera Bacillus, norank_o_Gaiellales, Roseiflexus, and norank_o_Gemmatimonadaceae were significantly more than that of the CS. Redundancy analysis at the genus level indicated that the available phosphate played a key role in the bacterial community distribution, and its role was negatively correlated with soil pH, organic matter content, alkali-hydrolyzable nitrogen, and available potassium contents. Interaction network analysis further demonstrated that greater diversity at the genus level existed in the SS network and formed a stable network. Additionally, the species of Mycobacterium, Cyanobacteria, and Rhodobiaceae are the key components that sustain the network stability. Seven clusters of orthologous groups exhibited significant differences between SS and CS. Moreover, 55 bacterial strains with distinct antagonistic activities to R. solancearum were isolated and identified from the healthy tomato plant rhizosphere soil of the CS.
Our findings indicate that the bacterial diversity and interaction network differed between the CS and SS samples, providing a good foundation in the study of bacterial wilt.
茄青枯雷尔氏菌是最臭名昭著的土传植物病原菌之一。它会导致许多经济上重要作物的严重萎蔫病，具有致命影响。人们认为，病害抑制土壤中的微生物群落可以促进作物的抗病性，因此，评估抑制土壤（SS）和促进土壤（CS）之间的微生物群落及其相互作用特征将有助于了解抗性机制。为此，分析了细菌群落结构、与土壤化学性质的相关分析、SS（近三年无病害）和 CS（严重细菌性萎蔫病）的相互作用网络。
SS 中发现了更高的细菌群落多样性指数，诺卡氏菌、盖氏菌和未分类的放线菌门相对丰度明显高于 CS。此外，芽孢杆菌、未分类的 Gaiellales、玫瑰色杆菌和未分类的 Gemmatimonadaceae 的相对丰度明显高于 CS。属水平的冗余分析表明，有效磷在细菌群落分布中起着关键作用，其作用与土壤 pH、有机质含量、碱解氮和有效钾含量呈负相关。相互作用网络分析进一步表明，SS 网络中存在更大的属水平多样性，并形成了一个稳定的网络。此外，分枝杆菌、蓝细菌和根瘤菌科的物种是维持网络稳定的关键成分。SS 和 CS 之间有 7 个聚类的直系同源群表现出显著差异。此外，从 CS 的健康番茄植物根际土壤中分离并鉴定出 55 株对茄青枯雷尔氏菌具有明显拮抗活性的细菌菌株。
我们的研究结果表明，CS 和 SS 样本之间的细菌多样性和相互作用网络存在差异，为细菌性萎蔫病的研究提供了良好的基础。
