Jujube development and ripening process provides a two-stage coloration model: ZjHY5-mediated flavonoid biosynthesis...

Area of Science:

• Plant Biology
• Fruit Ripening
• Pigmentation Genetics

Background:

• Fruit color is crucial for market value in jujube.
• The 'Dongzao' cultivar shows a unique two-stage ripening coloration.
• Molecular mechanisms of jujube fruit pigmentation are poorly understood.

Purpose of the Study:

• To elucidate the pigment composition and regulatory pathways of jujube fruit's two-stage coloration.
• To establish a molecular framework for jujube fruit pigmentation.

Main Methods:

• Bagging experiments to assess light dependency.
• Multi-omics analyses for comprehensive molecular profiling.
• Gene functional validation using in vivo assays.

Main Results:

• Reddish-brown stage (expansion) is light-dependent, involving flavonols/anthocyanins regulated by ZjHY5 activating ZjUFGT and ZjGT3.
• Deep-red stage (maturity) is light-independent, driven by ethylene-induced phenolic oxidation via ZjPPO1.
• A novel dual-stage coloration model for jujube fruit was established.

Conclusions:

• ZjHY5 acts as a key regulator for light-dependent flavonoid biosynthesis during jujube expansion.
• Ethylene signaling through ZjPPO1 controls light-independent browning via phenolic oxidation during ripening.
• Understanding these pathways offers strategies for improving jujube fruit color quality.