Abstract
BACKGROUND: Steroidal glycoalkaloids (SGAs), derived from cholesterol, act as natural defenses against pathogens and pests. In cultivated potatoes, α-solanine and α-chaconine are the primary SGAs, distributed throughout the plant, with their biosynthesis mechanisms differing across various tissues. The variation in SGAs content between the cortex and perimedullary zone reflects tissue-specific metabolic regulation in potato tuber. Higher SGAs levels in the cortex may enhance defense against external threats. This spatial distribution provides a theoretical basis for breeding strategies aimed at balancing resistance and food quality by regulating SGAs accumulation in specific tissues of potato tubers. Excessive levels of SGAs in potato tubers can compromise both their quality and edibility. Additionally, SGAs exhibit pharmacological properties, including anti-protozoal, antibacterial, antiviral, anti-tumor, and anti-inflammatory effects. RESULTS: This study conducted genome-wide association study (GWAS) on SGAs content in the cortex and perimedullary zone of 117 diverse potato germplasm accessions, utilizing 22,983,689 high-quality SNPs. Candidate genes were subjected to analyses of stability, pleiotropy, GO and KEGG enrichment, and haplotype profiling. Twelve candidate genes associated with SGAs biosynthesis in potato tubers were identified, encoding UDP-glycosyltransferase superfamily proteins (Soltu.DM.11G005750, Soltu.DM.11G005760, Soltu.DM.11G005770, Soltu.DM.11G005820), fatty acid hydroxylase superfamily proteins (Soltu.DM.01G029600, Soltu.DM.01G029610, Soltu.DM.01G029620, Soltu.DM.01G029640, Soltu.DM.01G029650, Soltu.DM.10G008360), alkaline/neutral invertase (Soltu.DM.11G006090), and pleiotropic drug resistance (Soltu.DM.11G006080). CONCLUSIONS: This study provides a theoretical basis for elucidating the genetic mechanisms underlying SGAs biosynthesis in potatoes and will facilitate the breeding of new potato varieties.