Tendril morphogenesis is regulated by a CsaTEN-CsaUFO module in cucumber

Area of Science:

• Plant morphology
• Evolutionary developmental biology
• Molecular genetics

Background:

• Tendrils are crucial for plant climbing ability, representing a significant evolutionary innovation.
• The molecular mechanisms underlying tendril morphogenesis remain largely unexplored.
• A mutant defective in tendril development (tmd1) was identified in cucumber, exhibiting leaf-like structures instead of tendrils.

Purpose of the Study:

• To elucidate the molecular basis of tendril morphogenesis in cucumber.
• To identify the gene responsible for the tmd1 mutant phenotype.
• To understand the regulatory network controlling tendril development.

Main Methods:

• Map-based cloning to identify the causal gene.
• Quantitative PCR (qPCR) for gene expression analysis.
• Bioinformatic analysis, yeast one-hybrid, electrophoretic mobility shift assay (EMSA), and luciferase assays to investigate gene interactions and regulation.

Main Results:

• The candidate causal gene was identified as CsaUFO.
• A promoter deletion in the tmd1 mutant impaired CsaUFO expression.
• A conserved motif (motif 1) in the CsaUFO promoter, containing TCP binding sites, was found to be essential for regulation by CsaTEN.
• CsaTEN directly binds motif 1 and positively regulates CsaUFO expression.

Conclusions:

• A CsaTEN-CsaUFO regulatory module governs cucumber tendril morphogenesis.
• The evolution of tendrils in cucumber is linked to CsaTEN's regulation of CsaUFO.
• The identified conserved motif offers a potential target for engineering tendril-less crops within the Cucurbitaceae family.