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Article|29 Dec 2023|OPEN
MdSnRK1.1 interacts with MdGLK1 to regulate abscisic acid-mediated chlorophyll accumulation in apple
Yu-Ying Yang1,2 ,† , Xiu-Hong An3 ,† , Lin Rui1 , Guo-Dong Liu1 , Yi Tian3 and Chun-Xiang You1 , , Xiao-Fei Wang,1 ,
1State Key Laboratory of Crop Biology, Apple Technology Innovation Center of Shandong Province, Shandong Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An 271018, Shandong, China
2Key Laboratory of Chinese Herbal Medicine Biology and Cultivation, Ministry of Agriculture and Rural Affairs, Institute of Chinese Herbal Medicine, Hubei Academy of Agricultral Science, Enshi 445000, China
3National Engineering Research Center for Agriculture in Northern Mountainous Areas, Agricultural Technology Innovation Center in Mountainous Areas of Hebei Province, Hebei Agricultural University, Baoding 071000, Hebei, China
*Corresponding author. E-mail: youchunxiang@126.com,xfwang2004@163.com
†Both authors contributed equally to the study.

Horticulture Research 11,
Article number: uhad288 (2024)
doi: https://doi.org/10.1093/hr/uhad288
Views: 63

Received: 09 May 2023
Accepted: 17 Dec 2023
Published online: 29 Dec 2023

Abstract

Abscisic acid (ABA), as a plant hormone, plays a positive role in leaf chlorosis; however, the underlying molecular mechanism is less known. Our findings provide ABA treatment reduced the chlorophyll accumulation in apple, and Malus × domestica Sucrose Non-fermenting 1-Related Protein Kinase 1.1 (MdSnRK1.1) participates in the process. MdSnRK1.1 interacts with MdGLK1, a GOLDEN2-like transcription factor that orchestrates development of the chloroplast. Furthermore, MdSnRK1.1 affects MdGLK1 protein stability through phosphorylation. We found that Ser468 of MdGLK1 is target site of MdSnRK1.1 phosphorylation. MdSnRK1.1-mediated phosphorylation was critical for MdGLK1 binding to the target gene MdHEMA1 promoters. Collectively, our results demonstrate that ABA activates MdSnRK1.1 to degrade MdGLK1 and inhibit the accumulation of chlorophyll. These findings extend our understanding on how MdSnRK1.1 balances normal growth and hormone response.