Comparison of bacterial communities in soil samples with and without tomato bacterial wilt caused by Ralstonia solanacearum species complex

Abstract

Background: 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. Results: 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. Conclusions: 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.

Exploring Biocontrol Agents From Microbial Keystone Taxa Associated to Suppressive Soil: A New Attempt for a Biocontrol Strategy

“…Our study revealed that disease altered the network features of the soil and root microbiomes. In particular, the co-occurrence networks of the suppressive soil and healthy roots were more complex, with a higher number of edges, higher average degree, and clustering coefficient compared with the networks of the conducive soil and infected roots ( Figure 4 ); this is consistent with previous studies ( Qi et al, 2019 ; Wei et al, 2019 ; Zhang et al, 2020 ). It was indicated that complex networks are more robust to external biotic and abiotic stresses than simple networks ( Santolini and Barabási, 2018 ).…”

“…The soil with low disease incidence even in the coexistence of susceptible plants and pathogens was defined as disease-suppressive soil. The mechanisms behind soil-mediated suppression of diseases, such as bacterial wilt disease in tobacco ( Qi et al, 2019 ; Zhang et al, 2020 ), Fusarium wilt in vanilla ( Xiong et al, 2017 ), Rhizoctonia solani in sugar beet ( Mendes et al, 2011 ), and black root rot in tobacco ( Kyselkova et al, 2009 ), have been extensively investigated. The soil microbiome has been deciphered in detail, and it has been found that the soil compositions between suppressive and conducive soils are distinct, although they share similar geographical and climatic conditions, as well as the same agronomic management.…”

Maize (Zea Mays L.) Genotypes Induce the Changes of Rhizosphere Microbial Communities

“…We found different genotypes of connectors and module hubs and differences between periods. In the seedling stage, the connectors found in N were all related to functions such as cellulose degradation and plant growth and development (Koeck et al 2016;Zhang et al 2020). The connector found in QZ was related to bacterial exopolysaccharides (EPSs), which can provide the host plant with antioxidants and protection from corrosive pathogens (Supplementary Table S4) (Bouchotroch et al 2000;Chi et al 2019).…”

Myxococcus xanthus R31 Suppresses Tomato Bacterial Wilt by Inhibiting the Pathogen Ralstonia solanacearum With Secreted Proteins

“…The pathogen R. solanacearum is a complex species with obvious physiological differentiation and genetic diversity and a very wide host range. R. solanacearum can infect more than 200 species in 54 families of plants (Prior et al, 2016), including tomato, tobacco, potato, banana, pepper, etc., thereby posing a serious threat to food security (Zhang et al, 2020). TBW is a vascular disease that often breaks out under the conditions of high temperatures and high humidity (Choi et al, 2020).…”