Genomic insights on fighting bacterial wilt by a novel Bacillus amyloliquefaciens strain Cas02

Abstract

Bacterial wilt, caused by the Ralstonia solanacearum, can infect several economically important crops. However, the management strategies available to control this disease are limited. Plant growth-promoting rhizobacteria (PGPR) have been considered promising biocontrol agents. In this study, Bacillus amyloliquefaciens strain Cas02 was isolated from the rhizosphere soil of healthy tobacco plants and evaluated for its effect on plant growth promotion and bacterial wilt suppression. Strain Cas02 exhibited several growth-promoting-related features including siderophore production, cellulase activity, protease activity, ammonia production and catalase activity. Moreover, strain Cas02 showed a significant inhibitory growth effect on R. solanacearum, and its active substances were separated and identified to be macrolactin A and macrolactin W by HPLC-DAD-ESI-MS/MS. Both greenhouse and field experiments demonstrated a good performance of Cas02 in plant growth promotion and bacterial wilt suppression. To explore the underlying genetic mechanisms, complete genome sequencing was performed and the gene clusters responsible for antibacterial metabolites expression were identified. Overall, these findings suggest that the strain Cas02 could be a potential biocontrol agent in bacterial wilt management and a source of antimicrobial compounds for further exploitation.

Biocontrol activity and action mechanism of Bacillus velezensis strain SDTB038 against Fusarium crown and root rot of tomato

“…Fusarium crown and root rot of tomato is a soilborne disease that has spread all over the world and seriously threatens tomato quality and production (Chu et al, 2021). After decades of research abroad, a variety of resources have been identified, including microorganisms such as B. amyloliquefaciens, B. cereus, and Rhizobium.…”

“…With the plants watered with 30 ml sterile liquid LB as the control, the rhizosphere soil, root tissue, stem base and leaves of tomato plants were taken 1, 2, 3, 4, 5, 6, 7, 14, 21, 28 and 60 d after root irrigation. The labeled strains were recovered from a plate containing 100 mg/l rifampicin, and the colonization of the labeled strains at different times and in different plant parts was analyzed (Chu et al, 2021). Scanning electron microscopy was performed according to a previous method (Guo et al, 2017).…”

“…The disease has seriously restricted the development of facility production of tomato (Deng et al, 2022). Although it is a very damaging pathogen to tomatoes, the management strategies for controlling the pathogen are limited (Cao et al, 2018), and there is an urgent need for a better way to control this disease to ensure production safety, reduce losses and increase outputs (Chu et al, 2021).…”

An avirulent Ralstonia solanacearum strain FJAT1458 outcompetes with virulent strain and induces tomato plant resistance against bacterial wilt

“…are well-known BCAs. 8,9 Numerous studies have reported that avirulent RS strains can effectively reduce the severity of BW disease. 10,11 In our previous studies, an avirulent strain, FJAT1458, had been isolated from a tomato host with high purity and the observed control efficiencies of 100 and 63.80% in pot and field experiments, respectively.…”

“…Avirulent strains of RS, Bacillus spp., and Streptomyces spp. are well‐known BCAs 8,9 . Numerous studies have reported that avirulent RS strains can effectively reduce the severity of BW disease 10,11 .…”