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

The Plant Cell, Volume 34, Issue 5, May 2022, Pages 2001–2018

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/

Figure 1: Distribution of YR response in the Vavilov wheat diversity panel evaluated in seedling (SLG) and adult plant field environments in 2014, 2015 and 2016. The boxplot shows the median value with upper and lower quartile range and overlaid green dots are the jittered row data points, while the red dot represents the mean disease score; the half violin plot represents the estimated density distribution