<i>AHK3</i>-Mediated Cytokinin Signaling Is Required for the Delayed Leaf Senescence Induced by <i>SSPP</i>

• Main Authors: Yanan Wang, Xiyu Zhang, Yanjiao Cui, Lei Li, Dan Wang, Yuanyuan Mei, Ning Ning Wang
• Format: Article
• Language: English
• Published: MDPI AG 2019-04-01
• Series: International Journal of Molecular Sciences
• Subjects: cytokinin signaling; AHK3; leaf senescence; SSPP
• Online Access: https://www.mdpi.com/1422-0067/20/8/2043

Leaf senescence is a highly-programmed developmental process regulated by an array of multiple signaling pathways. Our group previously reported that overexpression of the protein phosphatase-encoding gene <i>SSPP</i> led to delayed leaf senescence and significantly enhanced cytokinin responses. However, it is still unclear how the delayed leaf senescence phenotype is associated with the enhanced cytokinin responses. In this study, we introduced a cytokinin receptor <i>AHK3</i> knockout into the <i>35S:SSPP</i> background. The phenotypic analysis of double mutant revealed that <i>AHK3</i> loss-of-function reversed the delayed leaf senescence induced by <i>SSPP</i>. Moreover, we found the hypersensitivity of <i>35S:SSPP</i> to exogenous cytokinin treatment disappeared due to the introduction of <i>AHK3</i> knockout. Collectively, our results demonstrated that <i>AHK3</i>-mediated cytokinin signaling is required for the delayed leaf senescence caused by <i>SSPP</i> overexpression and the detailed mechanism remains to be further elucidated.