Phenotypic Diversity and Association Mapping of Ascorbic Acid Content in Spinach

Area of Science:

• Plant genetics
• Nutritional science
• Agricultural breeding

Background:

• Ascorbic acid (vitamin C) is vital for human health and acts as an antioxidant in plants.
• Spinach is a nutritious vegetable, and enhancing its nutritional content, particularly vitamin C, is a key breeding objective.
• Limited knowledge exists regarding the diversity of vitamin C content within spinach germplasm.

Purpose of the Study:

• To screen a diverse spinach panel for ascorbic acid (AsA) content variability.
• To conduct a genome-wide association study (GWAS) to identify genetic markers associated with AsA content.
• To explore the potential of identified markers for spinach breeding programs.

Main Methods:

• Screening of 352 worldwide spinach accessions for AsA content.
• Genome-wide association study using Generalized Linear Model (GLM), Compressed Mixed Linear Model (CMLM-P3D), and perMarker models.
• Functional annotation analysis of associated markers.

Main Results:

• High variability in AsA content was observed across the spinach germplasm.
• A total of 490 significant markers associated with AsA content were identified across all six chromosomes.
• 27 markers were consistently identified by all three GWAS models, indicating robust associations.
• Bioinformatic analysis confirmed the utility of identified markers in differentiating high and low AsA content accessions.

Conclusions:

• Spinach germplasm possesses significant genetic diversity for AsA content, valuable for cultivar improvement.
• The identified markers provide a foundation for marker-assisted selection in breeding programs to enhance vitamin C in spinach.
• High AsA content accessions can serve as parents for developing improved spinach varieties with enhanced nutritional value.