Functional Dissection of Auxin Response Factors in Regulating Tomato Leaf Shape Development

• Published in: Frontiers in plant science 2018-07, Vol.9, p.957-957
• Main Authors: Wu, Lingjie, Tian, Zhendong, Zhang, Junhong
• Format: Article
• Language: English
• Subjects: auxin; development; leaf shape; Plant Science; SlARFs; SlIAA9; tomato
• ISSN: 1664-462X; 1664-462X
• DOI: 10.3389/fpls.2018.00957

The phytohormone auxin is involved in many aspects of plant growth and developmental processes. The tomato Aux/IAA transcription factor SlIAA9/ENTIRE/E plays an important role in leaf morphogenesis and fruit development, and the gene encodes a protein from the Aux/IAA family of auxin response repressors. Both -RNAi transgenic and ( ) mutant plants reduce the leaf complexity in tomato, but the underlying mechanism is not yet completely resolved. Auxin signaling is known to regulate target genes expression via Aux/IAA and ARFs (auxin response factors) transcriptional regulators. ARFs mediate a wide range of developmental processes. Through an Y2H (yeast two-hybrid) assay coupled with expression profiling of the genes family, we identified a group of ARFs: SlARF6A, SlARF8A, SlARF8B, and SlARF24. Pull-down and BiFC (Bimolecular Fluorescence Complementation) results demonstrated that these SlARFs interact with SlIAA9 and , and the mutation altered the expression patterns of multiple . The simple leaves of the mutant were partially converted to wild-type compound leaves by VIGS (virus-induced gene silencing) of these four . Furthermore, IAA content in these samples was significantly increased compared to the mutant. In addition, SlARF6A and SlARF24 bound to the promoter and act as transcriptional activators to regulate genes expression involved in leaflet initiation. It may also suggest that SlARFs regulate leaf morphology through direct binding to auxin-responsive genes in the absence of SlIAA9, providing an insight for the role of in leaf shape development.