Open AccessSISTER OF TM3 activates FRUITFULL1 to regulate inflorescence branching in tomato
Author(s) -
Xiaotian Wang,
Zhiqiang Liu,
Shuai Sun,
Jianxin Wu,
Li Ren,
Haijing Wang,
Xia Cui
Publication year - 2021
Publication title -
horticulture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.947
H-Index - 31
eISSN - 2662-6810
pISSN - 2052-7276
DOI - 10.1038/s41438-021-00677-x
Subject(s) - inflorescence , biology , primordium , phenotype , mutant , arabidopsis , meristem , genetics , gene , botany
Selection for favorable inflorescence architecture to improve yield is one of the crucial targets in crop breeding. Different tomato varieties require distinct inflorescence-branching structures to enhance productivity. While a few important genes for tomato inflorescence-branching development have been identified, the regulatory mechanism underlying inflorescence branching is still unclear. Here, we confirmed that SISTER OF TM3 (STM3), a homolog of Arabidopsis SOC1, is a major positive regulatory factor of tomato inflorescence architecture by map-based cloning. High expression levels of STM3 underlie the highly inflorescence-branching phenotype in ST024. STM3 is expressed in both vegetative and reproductive meristematic tissues and in leaf primordia and leaves, indicative of its function in flowering time and inflorescence-branching development. Transcriptome analysis shows that several floral development-related genes are affected by STM3 mutation. Among them, FRUITFULL1 ( FUL1 ) is downregulated in stm3cr mutants, and its promoter is bound by STM3 by ChIP-qPCR analysis. EMSA and dual-luciferase reporter assays further confirmed that STM3 could directly bind the promoter region to activate FUL1 expression. Mutation of FUL1 could partially restore inflorescence-branching phenotypes caused by high STM3 expression in ST024. Our findings provide insights into the molecular and genetic mechanisms underlying inflorescence development in tomato.