Overexpression of a novel peanutNBS‐LRRgeneAhRRS5enhances disease resistance toRalstonia solanacearumin tobacco

Abstract

SummaryBacterial 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 AhRRS5 from peanut, which was up‐regulated in both resistant and susceptible peanut cultivars in response to R. solanacearum. The product of AhRRS5 was localized in the nucleus. Furthermore, treatment with phytohormones such as salicylic acid (SA), abscisic acid (ABA), methyl jasmonate (MeJA) and ethephon (ET) increased the transcript level of AhRRS5 with diverse responses between resistant and susceptible peanuts. Abiotic stresses such as drought and cold conditions also changed AhRRS5 expression. Moreover, transient overexpression induced hypersensitive response in Nicotiana benthamiana. Overexpression of AhRRS5 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 (NPR1) and non‐race‐specific disease resistance 1 were also up‐regulated in response to the pathogen. These results indicate that AhRRS5 participates in the defence response to R. solanacearum through the crosstalk of multiple signalling pathways and the involvement of NPR1 and R gene signals for its resistance. This study may guide the resistance enhancement of peanut and other economic crops to bacterial wilt disease.

Next‐generation sequencing identified genomic region and diagnostic markers for resistance to bacterial wilt on chromosome B02 in peanut (Arachis hypogaea L.)

“…Recently, Zhang et al . () overexpressed the peanut CNL gene, AhRRS5 , in tobacco and found that the BWR of transgenic lines enhanced. Therefore, the CNL genes might be an important type of R‐genes for BWR in peanut.…”

“…Through BLAST, we found this BAC clone located on chromosome B04 (Table S10). In addition, Zhang et al (2017) isolated NBS-LRR gene AhRRS5 in Yueyou 92 and reported the overexpression of AhRRS5 in tobacco enhanced BWR. Through BLAST, we found AhRRS5 located on chromosome A05 or B05 (Table S10).…”

“…In addition, Zhang et al . () reported that the overexpression of the peanut NBS‐LRR gene AhRRS5 in tobacco enhanced BWR of transgenic lines. These results indicated the potential use of R‐genes to control bacterial wilt across species.…”

“…Interestingly, when RRS1-R/RPS4 was transferred into tomato, transgenic lines exhibited resistance to R. solanacearum (Narusaka et al, 2013). In addition, Zhang et al (2017) reported that the overexpression of the peanut NBS-LRR gene AhRRS5 in tobacco enhanced BWR of transgenic lines. These results indicated the potential use of R-genes to control bacterial wilt across species.…”

Resistance against Ralstonia solanacearum in tomato depends on the methionine cycle and the γ‐aminobutyric acid metabolic pathway

“…Ralstonia solanacearum is a soil-borne pathogen that causes bacterial wilt, a destructive disease in tomato (Solanum lycopersicum) leading to substantial losses in tropical and other regions with warm temperature (Salanoubat et al, 2002). Ralstonia solanacearum is a soil-and waterborne bacterium which invades and colonizes tomato plants via root wounds; it eventually enters the xylem vessels and causes the collapse of infected tomato plants (Huang and Allen, 2000;Zhang et al, 2017). Breeding of resistant and tolerant tomato cultivars has proven to be the most effective approach for the management of R. solanacearum, as is the case for many other plant pathogens (Thoquet et al, 1996).…”