Two Novel RING-Type Ubiquitin Ligases, RGLG3 and RGLG4, Are Essential for Jasmonate-Mediated Responses in Arabidopsis1[C][W][OA]

• Published in: Plant physiology (Bethesda) 2012-08, Vol.160 (2), p.808-822
• Main Authors: Zhang, Xu, Wu, Qian, Ren, Jiao, Qian, Wanqiang, He, Shanping, Huang, Kuowei, Yu, XiangChun, Gao, Yin, Huang, Ping, An, Chengcai
• Format: Article
• Language: English
• Subjects: Development and Hormone Action
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.112.203422

Jasmonates ( JAs ) regulate various stress responses and development processes in plants, and the JA pathway is tightly controlled. In this study, we report the functional characterization of two novel RING-type ubiquitin ligases, RING DOMAIN LIGASE3 (RGLG3) and RGLG4, in modulating JA signaling. Both RGLG3 and RGLG4 possessed ubiquitin ligase activities and were widely distributed in Arabidopsis ( Arabidopsis thaliana ) tissues. Altered expression of RGLG3 and RGLG4 affected methyl JA -inhibited root growth and JA -inductive gene expression, which could be suppressed by the coronatine insensitive1 ( coi1 ) mutant. rglg3 rglg4 also attenuated the inhibitory effect of JA -isoleucine-mimicking coronatine on root elongation, and consistently, rglg3 rglg4 was resistant to the coronatine-secreting pathogen Pseudomonas syringae pv tomato DC3000, suggesting that RGLG3 and RGLG4 acted in response to the coronatine and promoted JA -mediated pathogen susceptibility. In addition, rglg3 rglg4 repressed wound-stunted plant growth, wound-stimulated expression of JA -responsive genes, and wound-induced JA biosynthesis, indicating their roles in JA -dependent wound response. Furthermore, both RGLG3 and RGLG4 responded to methyl JA , P. syringae pv tomato DC3000, and wounding in a COI1-dependent manner. Taken together, these results indicate that the ubiquitin ligases RGLG3 and RGLG4 are essential upstream modulators of JA signaling in response to various stimuli.