Study : A Functional Allele of CsFUL1 Regulates Fruit Length through Repressing CsSUP and Inhibiting Auxin Transport in Cucumber

Identification

Name
A Functional Allele of CsFUL1 Regulates Fruit Length through Repressing CsSUP and Inhibiting Auxin Transport in Cucumber
Identifier
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Source
Description
Cucumber (Cucumis sativus L.) is an important vegetable crop bearing fleshy pepo fruits that harvested immature. The fruit length is one of the most important agricultural traits that directly determine the fruit yield and affects fruit quality, but the regulatory mechanism of fruit length variation remains elusive. Here we found a FRUITFULL-like MADS-box gene CsFUL1 functions as a key repressor for fruit length regulation in cucumber. The expression of CsFUL1 is highly enriched in male flowers and fruits, and negatively correlated with fruit length in different cucumber lines. Notably, a key SNP in CsFUL1 was selected during cucumber domestication for long fruit. Ectopic expression of CsFUL1 was unable to rescue the indehiscent fruit phenotype of ful-1 in Arabidopsis. Overexpression of CsFUL1 resulted in increased floral organs and reduced fruit length, whereas knockdown of CsFUL1 led to elongated fruit in cucumber. Transcriptome and biochemical analyses showed that CsFUL1 regulates fruit length through two pathways: one by inhibiting the PIN-FORWED (PIN1/7)-mediated auxin transport and thus downregulates auxin related genes in the fruit, and the other by forming a tetramer with other MADS-box genes to repress the CsSUP-mediated cell division and cell expansion. In addition, we found that CsFUL1 promotes locule number variation through the classical CsWUS-CsCLV pathway. Our findings uncover the regulatory commonality and specificity during development of different fruit types, and provide an important candidate gene to customize fruit length during cucumber breeding. Overall design: Comparative analysis of fruit from two near-isogenic lines, WT(long fruit) and OX-29 (short fruit), was employed to discover genes and networks that regulate the fruit length. Two biological replicates were used from each line.

Genotype

Accession number Name Taxon