A CsTu-TS1 regulatory module promotes fruit tubercule formation in cucumber

Area of Science:

• Plant genetics
• Fruit development
• Agricultural science

Background:

• Fruit epidermal features, like tubercule size, are key quality traits in cucumber production.
• The genetic mechanisms controlling cucumber fruit tubercule formation are not well understood.

Purpose of the Study:

• To identify the genetic factors controlling cucumber fruit tubercule size.
• To elucidate the molecular mechanism of CsTS1 in regulating cucumber fruit development.

Main Methods:

• Map-based cloning was used to identify the tubercule size locus CsTS1.
• Quantitative real-time PCR (qRT-PCR) and RNA interference (RNAi) were employed to analyze CsTS1 expression and function.
• Transgenic complementation and gene silencing experiments were conducted in cucumber plants.
• Analysis of auxin content and related gene expression in transgenic fruits.

Main Results:

• The CsTS1 gene, encoding an oleosin protein, was identified as a key regulator of cucumber fruit tubercule size.
• Allelic variations in the CsTS1 promoter region correlated with differential gene expression and tubercule size.
• High CsTS1 expression positively correlated with larger fruit tubercules across multiple cucumber lines.
• CsTS1 positively regulates tubercule development, with expression peaking during formation and enlargement stages.
• The CsTu transcription factor directly binds to the CsTS1 promoter, enhancing its expression and promoting tubercule formation.

Conclusions:

• The study reveals CsTS1 as a crucial gene for cucumber fruit tubercule development.
• A novel regulatory mechanism involving the CsTu-TS1 complex in promoting cucumber fruit tubercule formation is proposed.
• Understanding this mechanism can aid in breeding cucumbers with desirable fruit quality traits.