Brassinosteroid Signaling Downstream Suppressor BIN2 Interacts with SLFRIGIDA-LIKE to Induce Early Flowering in Tomato

Abstract

Brassinosteroid (BR) signaling is very important in plant developmental processes. Its various components interact to form a signaling cascade. These components are widely studied in Arabidopsis; however, very little information is available on tomatoes. Brassinosteroid Insensitive 2 (BIN2), the downstream suppressor of BR signaling, plays a critical role in BR signal pathway, while FRIGIDA as a key suppressor of Flowering Locus C with overexpression could cause early flowering; however, how the BR signaling regulates FRIGIDA homologous protein to adjust flowering time is still unknown. This study identified 12 FRIGIDA-LIKE proteins with a conserved FRIGIDA domain in tomatoes. Yeast two-hybrid and BiFC confirmed that SlBIN2 interacts with 4 SlFRLs, which are sub-cellularly localized in the nucleus. Tissue-specific expression of SlFRLs was observed highly in young roots and flowers. Biological results revealed that SlFRLs interact with SlBIN2 to regulate early flowering. Further, the mRNA level of SlBIN2 also increased in SlFRL-overexpressed lines. The relative expression of SlCPD increased upon SlFRL silencing, while SlDWF and SlBIN2 were decreased, both of which are important for BR signaling. Our research firstly provides molecular evidence that BRs regulate tomato flowering through the interaction between SlFRLs and SlBIN2. This study will promote the understanding of the specific pathway essential for floral regulation.

Recent Advances in Studying the Regulation of Fruit Ripening in Tomato Using Genetic Engineering Approaches

“…BSs are capable of inducing early flowering. This is supported by the interaction of the suppressor of BIN2 signaling with the early flowering locus FRIGIDA [201]. There is evidence that canonical signaling pathways initiated by BRI1 are involved in xylem differentiation and wood formation in tomatoes through activation of the BZR1/2 transcription factors [202].…”

Recent Advances in Studying the Regulation of Fruit Ripening in Tomato

“…Brassinosteroids are capable of inducing early flowering. This is supported by the interaction of the suppressor of BIN2 signaling with the early flowering locus FRIGIDA [109]. There is evidence that canonical signaling pathways initiated by BRI1 are involved in xylem differentiation and wood formation in tomatoes through activation of the BZR1/2 transcription factors [110].…”

New Advances in the Study of Regulation of Tomato Flowering-Related Genes Using Biotechnological Approaches

“…Only now is the functional redundancy of transcription factors involved in flowering becoming apparent. Understanding the "dark horses" of regulatory cascades, such as ABA [195,268] and BSs [199,272,273], is also expanding. The ideas about the influence of epigenetic modifications [125,274,275], ncRNAs [248,262,[276][277][278], and external factors [3,279,280] on signaling regulation have been greatly expanded recently.…”