CYTOKININ-RESPONSIVE GATA FACTOR 1 negatively regulates ascorbic acid biosynthesis in non-heading Chinese cabbage.

Area of Science:

• Plant Genetics
• Molecular Biology
• Nutritional Science

Background:

• Ascorbic acid (AsA) is vital for human health, primarily sourced from fruits and vegetables.
• Genetic complexity underlies AsA accumulation in plants, necessitating detailed investigation.

Purpose of the Study:

• To investigate the genetic regulation of AsA biosynthesis in non-heading Chinese cabbage (NHCC).
• To identify key genes and regulatory mechanisms controlling AsA accumulation in NHCC.

Main Methods:

• Quantitative trait locus (QTL) analysis across multiple environments.
• Integrated QTL mapping and comparative transcriptome analysis.
• Gene silencing, overexpression, and protein-protein interaction studies.

Main Results:

• Identified 19 AsA-associated QTLs, with qAsA.A01.1 being environmentally stable.
• Discovered BcCGA1 (GATA transcription factor) as a negative regulator of AsA biosynthesis.
• BcCGA1 directly represses promoters of key AsA biosynthesis genes (BcGGP.c, BcGMP.b, BcKJC.c).
• BcCGA1 interacts with BcPSBO1, showing complex regulatory effects on AsA synthesis.

Conclusions:

• Elucidated a regulatory network involving BcCGA1 and BcPSBO1 in AsA biosynthesis.
• Established BcCGA1's role as a transcriptional repressor of AsA accumulation.
• Provided a theoretical foundation for breeding NHCC with enhanced AsA content.