2. Academic Validation
  3. Calcium-responsive phosphorylation of SlLHP1b epigenetically suppresses auxin synthesis to control drought-induced flower drop in tomato

Calcium-responsive phosphorylation of SlLHP1b epigenetically suppresses auxin synthesis to control drought-induced flower drop in tomato

  • Dev Cell. 2025 May 27:S1534-5807(25)00296-5. doi: 10.1016/j.devcel.2025.05.006.
Siqi Ge 1,  Sai Wang 1,  Xianfeng Liu 1,  Lina Cheng 1,  Ruizhen Li 1,  Yang Liu 1,  Yue Cai 1,  Sida Meng 1,  Changhua Tan 1,  Cai-Zhong Jiang 2,  Mingfang Qi 1,  Tianlai Li 3,  Tao Xu 4
Affiliations

Affiliations

  • 1 College of Horticulture, Shenyang Agricultural University, Shenyang 110866, China; Key Laboratory of Protected Horticulture of Ministry of Education, Shenyang, China.
  • 2 Crops Pathology and Genetic Research Unit, United States Department of Agriculture Agricultural Research Service, Davis, CA, USA; Department of Plant Sciences, University of California at Davis, Davis, CA 95616, USA.
  • 3 College of Horticulture, Shenyang Agricultural University, Shenyang 110866, China; Key Laboratory of Protected Horticulture of Ministry of Education, Shenyang, China. Electronic address: tianlaili@126.com.
  • 4 College of Horticulture, Shenyang Agricultural University, Shenyang 110866, China; Key Laboratory of Protected Horticulture of Ministry of Education, Shenyang, China. Electronic address: syauxutao@syau.edu.cn.
PMID: 40460834 DOI: 10.1016/j.devcel.2025.05.006
Abstract

Drought causes the abscission of flowers and fruits, thereby reducing yields. Although trimethylation of histone H3 in the lysine 27 (H3K27me3)-dependent pathway has been shown to control drought responses, the mechanisms underlying drought-induced abscission remain unknown. In this study, we showed that drought-induced Calcineurin B-like11 (SlCBL11) upregulation activated the CBL-interacting protein kinase10 (SlCIPK10) to phosphorylate like heterochromatin protein 1b (SlLHP1b) at Thr387 and Thr389, respectively, in stamens of tomato (Solanum lycopersicum). Phosphorylation at Thr389 improved SlLHP1b stability, and phosphorylation at Thr387/Thr389 enhanced SlLHP1b binding ability to H3K27me3. Hence, SlLHP1b-dependent epigenetic silencing of the expression of SlYUC in stamens was promoted, which decreased the Auxin content in stamens, causing the disruption of the Auxin gradient in the abscission zone, and eventually flower drop in tomatoes. Overall, we showed a mechanism by which CA2+ signaling controls H3K27me3 through the SlCBL11-SlCIPK10-SlLHP1b module to inhibit Auxin synthesis during drought-induced flower drop.

Keywords

H3K27me3; auxin synthesis; calcium signaling; drought; flower drop; phosphorylation; tomato.

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