The SlARF4-SlHB8 regulatory module mediates leaf rolling in tomato

• Published in: Plant science (Limerick) Vol. 335; p. 111790
• Main Authors: Liu, Xiaojuan, Lin, Yuxiang, Wu, Caiyu, Yang, Yang, Su, Deding, Xian, Zhiqiang, Zhu, Yiyi, Yu, Canye, Hu, Guojian, Deng, Wei, Li, Zhengguo, Bouzayen, Mondher, Chen, Riyuan, Hao, Yanwei
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2023; Elsevier
• Subjects: Leaf rolling; Life Sciences; SlARF4; SlHB8; Transcriptional regulation; Vegetal Biology; Leaf rolling; SlARF4; Transcriptional regulation; SlHB8
• ISSN: 0168-9452; 1873-2259
• DOI: 10.1016/j.plantsci.2023.111790

Leaf is the main photosynthetic organ in plants and the primary energy source all along the plant life. Given the beneficial role of leaf rolling in improving photosynthetic efficiency and yield in specific environmental conditions, a better understanding of the factors and molecular mechanisms underlying this process is highly suited. Previously, the SlARF4 knocking out mutant exhibited upward curly leaf showed higher resistance to water deficit which driving us to uncover the function of SlARF4 in regulating the curly leaf formation. In this study, we unraveled the unexplored role of the SlARF4-SlHB8 module of transcription factors in the development of leaf rolling. Both SlARF4 loss-of-function and SlHB8 overexpressing tomato plants exhibited upward-rolled leaves, reflecting the active role of the two genes in controlling leaf rolling. Dual-luciferase reporter assays and phenotypic analysis of hybrid progenies suggested that SlHB8 acts downstream of SlARF4 in curly leaf formation. SlARF4 and SlHB8 influence the development of leaf palisade tissues via modulating the expression of genes associated with curly leaf formation. SEM analysis revealed no significant differences in leaf epidermal cells between the two leaf-rolling mutants and the wild type, indicating that curly leaves of arf4 and SlHB8-OE do not result from the asymmetric leaf epidermal cell growth. Our data provide novel insight into the molecular mechanism of abaxial-adaxial determination involving SlARF4 and SlHB8 and reveals that leaf rolling operates via different regulation mechanisms in tomato and Arabidopsis model plant. •In tomato, SlARF4 and SlHB8 are located both in the adaxial surface and abaxial surface.•SlARF4 could bind to SlHB8 promoter and inhibit its expression.•Loss of function of SlARF4 results in the up-regulation of SlHB8 which defines the upward leaf rolling.•SlHB8 could bind to rolling leaf regulators’ (SlLBD and SlAGO7) promoters to induce their expression level.•SlARF4 is repressed by the tasi-ARF which is positively regulated by the SlAGO7.