Integrated transcriptomic and metabolomic analysis revealed the response of resistant variety Zhonghua 6 to the infection of Ralstonia solanacearum in peanut.

Peanut (Arachis hypogaea L.) is an important oil and economic crop, and its production has long been severely threatened by soil-borne bacterial wilt (BW) disease. However, the molecular mechanism of host resistance to it has not yet been systematically elucidated. In this study, the highly resistant peanut variety Zhonghua 6 was used as the research object. Through transcriptomic analysis, a total of 1,122 differentially expressed genes (DEGs) were identified between carefully designed treatment and control groups. WGCNA analysis led to the discovery of 14 hub genes, including two cytochrome P450 genes and a UGDH gene. Through metabolomic analysis, 1,614 differentially accumulated metabolites (DAMs) were identified, and 6-methylcoumarin, erucamide, and piceatannol were confirmed to inhibit the growth of R. solanacearum. Integrative transcriptomic and metabolomic analyses uncovered a comprehensive immune regulatory network consisted of genes involved in key pathways associated with R. solanacearum infection such as MAPK signaling, plant hormone signal transduction, phenylpropanoid biosynthesis, flavonoid biosynthesis, and ABC transporter. Overall, these results provide new insights into the molecular mechanisms governing peanut resistance to R. solanacearum, which might assist in the mining of resistance-related genes, developing of new disease control measures as well as breeding of novel disease-resistant cultivars in peanut.