Leelyn Chong, Rui Xu, Pengcheng Huang, Pengcheng Guo, Mingku Zhu, Hai Du, Xiaoli Sun, Lixia Ku, Jian-Kang Zhu, Yingfang Zhu

Plant Cell; 2022 Apr 26; 34(5): 2001-2018.  doi: 10.1093/plcell/koac026.

Abstract

Flowering is a critical agricultural trait that substantially affects tomato fruit yield. Although drought stress influences flowering time, the molecular mechanism underlying drought-regulated flowering in tomato remains elusive. In this study, we demonstrated that loss of function of tomato OPEN STOMATA 1 (SlOST1), a protein kinase essential for abscisic acid (ABA) signaling and abiotic stress responses, lowers the tolerance of tomato plants to drought stress. slost1 mutants also exhibited a late flowering phenotype under both normal and drought stress conditions. We also established that SlOST1 directly interacts with and phosphorylates the NAC (NAM, ATAF and CUC)-type transcription factor VASCULAR PLANT ONE-ZINC FINGER 1 (SlVOZ1), at residue serine 67, thereby enhancing its stability and nuclear translocation in an ABA-dependent manner. Moreover, we uncovered several SlVOZ1 binding motifs from DNA affinity purification sequencing analyses and revealed that SlVOZ1 can directly bind to the promoter of the major flowering-integrator gene SINGLE FLOWER TRUSS to promote tomato flowering transition in response to drought. Collectively, our data uncover the essential role of the SlOST1-SlVOZ1 module in regulating flowering in response to drought stress in tomato and offer insights into a novel strategy to balance drought stress response and flowering.

See https://pubmed.ncbi.nlm.nih.gov/35099557/ or

https://academic.oup.com/plcell/article-abstract/34/5/2001/6517789?redirectedFrom=fulltext&login=false