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, to conduct the microbial community and their interaction characteristics between suppressive soil (SS) and conducive soil (CS) will help to understand resistance mechanism. Here, 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: Compared with CS, a higher bacterial community diversity index was found in SS , and the relative abundance of main genera Bacillus , Gaiellales , Roseiflexus , Gemmatimonadaceae , Nocardioides , and Anaerolineacear reached significant levels. 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. 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.

Combating biotic stresses in plants by synthetic microbial communities: Principles, applications and challenges

“…The rhizospheric microbiome of Ralstonia solanacearum infected tomato plants grown in soil suppressive to broad‐range phytopathogens had significantly greater bacterial community diversity than the rhizospheric microbiome of plants grown in disease conducive soil (Zhang et al, 2020). Available phosphate was determined as a critical factor shaping the bacterial communities.…”

Efficacy of indigenous plant growth-promoting rhizobacteria and Trichoderma strains in eliciting resistance against bacterial wilt in a tomato

“…Biological agents, well defined as living microorganisms, can expressively decrease the plant pathogen density (O'Brien 2017). Certain bacteria and fungi are discussed as plant growth-promoting rhizobacteria (PGPR) and plant growth-promoting fungi (PGPF), respectively, and their efficacy in controlling various plant diseases affected by plant pathogens has been extensively recognized (Abdelrahman et al 2016 andZhang et al 2020). Induced systemic resistance (ISR) is an improvement of plant selfprotective capability against different phytopathogens (Romera et al 2019).…”