The extensin protein SAE1 plays a role in leaf senescence and is targeted by the ubiquitin ligase SINA4 in tomato

作者：Lu, Han; Niu, Xiangli; Fan, Youhong; Yuan, Yulin; Huang, Li; Zhao, Bingyu; Liu, Yongsheng^*; Xiao, Fangming^*

来源：Journal of Experimental Botany, 2023, 74(18): 5635-5652.

DOI：10.1093/jxb/erad242

• CRISPR-Cas9
• extensin
• leaf senescence
• Solanum lycopersicum
• tomato
• ubiquitin ligase
• ubiquitination

Extensins are hydroxyproline-rich glycoproteins and generally play a structural role in cell wall integrity. In this study, we determined a novel role of tomato (Solanum lycopersicum) SENESCENCE-ASSOCIATED EXTENSIN1 (SAE1) in leaf senescence. Both gain- and loss-of-function analyses suggest that SAE1 plays a positive role in leaf senescence in tomato. Transgenic plants overexpressing SAE1 (SAE1-OX) exhibited premature leaf senescence and enhanced dark-induced senescence, whereas SAE1 knockout (SAE1-KO) plants displayed delayed development-dependent and dark-induced leaf senescence. Heterologous overexpression of SlSAE1 in Arabidopsis also led to premature leaf senescence and enhanced dark-induced senescence. In addition, the SAE1 protein was found to interact with the tomato ubiquitin ligase SlSINA4, and SlSINA4 promoted SAE1 degradation in a ligase-dependent manner when co-expressed in Nicotiana benthamiana leaves, suggesting that SlSINA4 controls SAE1 protein levels via the ubiquitin-proteasome pathway. Introduction of an SlSINA4-overexpression construct into the SAE1-OX tomato plants consistently completely eliminated accumulation of the SAE1 protein and suppressed the phenotypes conferred by overexpression of SAE1. Taken together, our results suggest that the tomato extensin SAE1 plays a positive role in leaf senescence and is regulated by the ubiquitin ligase SINA4. @@@ Expression of the extension protein SAE1 plays a role in leaf senescence in tomato and is regulated by the ubiquitin ligase SINA4.

• 单位
  复旦大学; 四川大学