Identification of a Protein Content-Associated Gene in Peanut (Arachis hypogaea) and Functional Characterization of the Gene and Its Homolog in Arabidopsis thaliana

Peanut is a vital cash crop globally, and enhancing its seed protein content is essential for nutritional security. However, the genetic basis of seed protein content in peanut remains unclear. In this study, bulked segregant analysis combined with next-generation sequencing (BSA-Seq) was employed to isolate a candidate gene, AhSPC, associated with peanut seed protein content. Its function was then characterized in Arabidopsis thaliana through CRISPR/Cas9-mediated gene knockout and overexpression analysis. Gene editing of the homologous gene in Arabidopsis significantly reduced seed protein content in six lines, while two lines showed no obvious change. Overexpression of the AhSPC gene in Arabidopsis led to an increase in seed protein content in three transgenic lines, but some lines showed no significant change, or even a decrease. These inconsistent results might be attributed to functional redundancy, epigenetic modifications, resource competition, or feedback regulation mechanisms within the protein synthesis pathway. This study provides insights into the molecular mechanisms of peanut seed protein content regulation and offers a potential genetic target for molecular breeding.