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Article|23 Oct 2024|OPEN
NpCIPK6–NpSnRK1 module facilitates intersubgeneric hybridization barriers in water lily (Nymphaea) by reducing abscisic acid content
Ping Zhou1,2 , Jingwen Li1,2 , Huiyan Jiang1,2 , Zhijuan Yang3 , Chunqing Sun1,4 and Hongyan Wang5 , Qun Su5 , Qijiang Jin1,2 , Yanjie Wang1,2 , Yingchun Xu,1,2 ,
1Key Laboratory of Landscaping, Ministry of Agriculture and Rural Affairs, Key Laboratory of Biology of Ornamental Plants in East China, College of Horticulture, Nanjing Agricultural University, No. 666 Binjiang Avenue, Jiangbei New District, Nanjing, Jiangsu 210095, China
2Sanya Research Institute of Nanjing Agricultural University, Building 9, Wutong Industrial Park, Zhenzhou Road, Yazhou District, Sanya 572000, China
3College of Breeding and Multiplication, Hainan University (Sanya Institute of Breeding and Multiplication), Yazhou District Huanjin Road, Sanya, Hainan 570228, China
4Zhenjiang Institute of Agricultural Science in Jiangsu Hilly Areas, No. 1 Hongjing Road, Huayang Town, Jurong 212400, China
5Flower Research Institute, Guangxi Academy of Agricultural Science, 174 Daxue East Road, Nanning 530007, China
*Corresponding author. E-mail: xyc@njau.edu.cn

Horticulture Research 12,
Article number: uhae289 (2025)
doi: https://doi.org/10.1093/hr/uhae289
Views: 2265

Received: 20 May 2024
Accepted: 02 Oct 2024
Published online: 23 Oct 2024

Abstract

Prefertilization hybridization barriers are the main causes of intersubgeneric hybridization challenges in water lily. However, the mechanism underlying low compatibility between pollen and stigma of water lily remains unclear. This study demonstrates that CBL-interacting protein kinase 6 (CIPK6) responded to the signaling exchange between incompatible pollen and stigma through interactions with SNF1-related kinase 1 (SnRK1) and promotes the accumulation of SnRK1 protein. Activated SnRK1 interacted with 9-cis-epoxycarotenoid dioxygenase 2 (NCED2) to promote its degradation, thereby inhibiting abscisic acid (ABA) synthesis. A decrease in ABA content in the stigma impaired the ABA-mediated removal of reactive oxygen species (ROS), ultimately resulting in the rejection of the incompatible pollen by the stigma. Our results highlight the essential role of the NpCIPK6–NpSnRK1–NpNCED2 module in conferring intersubgeneric hybridization barriers in water lily by interfering with ABA synthesis and promoting ROS accumulation. This study offers valuable mechanistic insights into cellular signaling and reproductive barriers in water lily as well as across other biological contexts.