Overexpression of the peanut CLAVATA1-like leucine-rich repeat receptor-like kinase AhRLK1 confers increased resistance to bacterial wilt in tobacco

• Published in: Journal of experimental botany Vol. 70; no. 19; pp. 5407 - 5421
• Main Authors: Zhang, Chong, Chen, Hua, Zhuang, Rui-Rong, Chen, Yu-Ting, Deng, Ye, Cai, Tie-Cheng, Wang, Shuai-Yin, Liu, Qin-Zheng, Tang, Rong-Hua, Shan, Shi-Hua, Pan, Rong-Long, Chen, Li-Song, Zhuang, Wei-Jian
• Format: Journal Article
• Language: English
• Published: UK Oxford University Press 15.10.2019
• Subjects: Arachis - genetics; Arachis - metabolism; Disease Resistance; Nicotiana - genetics; Nicotiana - microbiology; Plant Diseases - genetics; Plant Diseases - microbiology; Plant Proteins - genetics; Plant Proteins - metabolism; Protein Serine-Threonine Kinases - genetics; Protein Serine-Threonine Kinases - metabolism; Ralstonia solanacearum - physiology; Research Papers; transgenic tobacco; defense signaling; Arachis hypogaea; Ralstonia solanacearum; AhRLK1; EDS1
• ISSN: 0022-0957; 1460-2431; 1460-2431
• DOI: 10.1093/jxb/erz274

Overexpression of a novel peanut CLAVATA1-like gene significantly enhanced the resistance to Ralstonia solanacearum in tobacco via defense response signaling associated with EDS1-mediated R-gene pathways. Abstract Bacterial wilt caused by Ralstonia solanacearum is a devastating disease affecting hundreds of plant species, yet the host factors remain poorly characterized. The leucine-rich repeat receptor-like kinase gene AhRLK1, characterized as CLAVATA1, was found to be up-regulated in peanut upon inoculation with R. solanacearum. The AhRLK1 protein was localized in the plasma membrane and cell wall. qPCR results showed AhRLK1 was induced in a susceptible variety but little changed in a resistant cultivar after inoculated with R. solanacearum. Hormones such as salicylic acid, abscisic acid, methyl jasmonate, and ethephon induced AhRLK1 expression. In contrast, AhRLK1 expression was down-regulated under cold and drought treatments. Transient overexpression of AhRLK1 led to a hypersensitive response (HR) in Nicotiana benthamiana. Furthermore, AhRLK1 overexpression in tobacco significantly increased the resistance to R. solanacearum. Besides, the transcripts of most representative defense responsive genes in HR and hormone signal pathways were significantly increased in the transgenic lines. EDS1 and PAD4 in the R gene signaling pathway were also up-regulated, but NDR1 was down-regulated. Accordingly, AhRLK1 may increase the defense response to R. solanacearum via HR and hormone defense signaling, in particular through the EDS1 pathway of R gene signaling. These results provide a new understanding of the CLAVATA1 function and will contribute to genetic enhancement of peanut.