A QTL of eggplant shapes the rhizosphere bacterial community, co-responsible for resistance to bacterial wilt.

Resistant crop cultivars can recruit beneficial rhizobacteria to resist disease. However, whether this recruitment is regulated by quantitative trait loci (QTL) is unclear. The role of QTL in recruiting specific bacteria against bacterial wilt (BW) is an important question of practical significance to disease management. Here, to identify QTL controlling BW resistance, Super-BSA was performed in F ₂ plants derived from resistant eggplant cultivar R06112 × susceptible cultivar S55193. The QTL was narrowed down through BC ₁ F ₁ -BC ₃ F ₁ individuals by wilting symptoms and KASP markers. Rhizosphere bacterial composition of R06112, S55193, and resistant individuals EB158 (with the QTL) and susceptible individuals EB327 (without QTL) from BC ₂ F ₁ generation were assessed by Illumina sequencing-based analysis, and the activation of plant immunity by the bacterial isolates was analyzed. Evidence showed that BW-resistant is controlled by one QTL located at the 270 kb region on chromosome 10, namely EBWR10 , and nsLTPs as candidate genes confirmed by RNA-Seq. EBWR10 has a significant effect on rhizobacteria composition and significantly recruits Bacillus . pp. A SynCom of three isolated Bacillus . pp trains significantly reduced the disease incidence, changed activities of CAT, PPO, and PAL and concentration of NO, H ₂ O ₂ , and O ₂ ^- , activated SA and JA signaling-dependent ISR, and displayed immune activation against Ralstonia solanacearum in eggplant. Our findings demonstrate for the first time that the QTL can recruit beneficial rhizobacteria, which jointly promote the suppression of BW. This method charts a path to develop the QTL in resistant cultivar-driven probiotics to ameliorate plant diseases.
Competing Interests: The authors declare that there are no conflicts of interest.
(© The Author(s) 2024. Published by Oxford University Press on behalf of Nanjing Agricultural University.)