PSC1, a basic/helix-loop-helix transcription factor controlling the purplish-red testa trait in peanut

Area of Science:

• Plant genetics
• Crop science
• Biochemistry

Background:

• Seed color is a crucial agronomic trait in peanuts, influencing nutritional and commercial value.
• Darker seed coats are sought after for their higher anthocyanin content.
• Identifying the genetic basis of seed color can aid in crop improvement.

Purpose of the Study:

• To identify the gene responsible for the purplish-red seed coat trait in peanuts.
• To elucidate the molecular mechanism regulating anthocyanin accumulation in the seed coat.
• To provide a genetic resource for breeding enhanced peanut varieties.

Main Methods:

• Bulk segregant analysis was employed to locate the causative gene.
• Transcriptomic and metabolomic analyses were performed to understand gene function.
• Gene expression, protein-protein interactions, and functional assays in model organisms were utilized.

Main Results:

• A novel gene, PURPLE RED SEED COAT1 (PSC1), encoding a basic/helix-loop-helix transcription factor, was identified.
• A 35-bp insertion in the PSC1 promoter increases PSC1 mRNA abundance, leading to purplish-red seed coats.
• PSC1 suppresses anthocyanidin reductase (ANR) expression by interacting with AhMYB7, promoting anthocyanin accumulation.

Conclusions:

• PSC1 is a key regulator of anthocyanin metabolism and seed coat color in peanuts.
• The identified PSC1 gene and its regulatory mechanism offer a valuable resource for breeding.
• Overexpression of PSC1 enhances anthocyanin content in both peanut and Arabidopsis.