Overexpression of a novel peanut NBS ‐ LRR gene A h RRS 5 enhances disease resistance to R alstonia solanacearum in tobacco

Bacterial wilt caused by Ralstonia solanacearum is a ruinous soilborne disease affecting more than 450 plant species. Efficient control methods for this disease remain unavailable to date. This study characterized a novel nucleotide‐binding site‐leucine‐rich repeat resistance gene Ah RRS 5 from peanut, which was up‐regulated in both resistant and susceptible peanut cultivars in response to R. solanacearum . The product of Ah RRS 5 was localized in the nucleus. Furthermore, treatment with phytohormones such as salicylic acid ( SA ), abscisic acid ( ABA ), methyl jasmonate (Me JA ) and ethephon ( ET ) increased the transcript level of Ah RRS 5 with diverse responses between resistant and susceptible peanuts. Abiotic stresses such as drought and cold conditions also changed Ah RRS 5 expression. Moreover, transient overexpression induced hypersensitive response in Nicotiana benthamiana . Overexpression of Ah RRS 5 significantly enhanced the resistance of heterogeneous tobacco to R. solanacearum , with diverse resistance levels in different transgenic lines. Several defence‐responsive marker genes in hypersensitive response, including SA , JA and ET signals, were considerably up‐regulated in the transgenic lines as compared with the wild type inoculated with R. solanacearum . Nonexpressor of pathogenesis‐related gene 1 ( NPR 1 ) and non‐race‐specific disease resistance 1 were also up‐regulated in response to the pathogen. These results indicate that Ah RRS 5 participates in the defence response to R. solanacearum through the crosstalk of multiple signalling pathways and the involvement of NPR 1 and R gene signals for its resistance. This study may guide the resistance enhancement of peanut and other economic crops to bacterial wilt disease.