The potato (Solanum tuberosum L.) ranks among the most consumed agricultural products globally and is nutrient-rich. Exposure of potato tubers’ epidermal and subcutaneous tissues to light results in greening and the production of neurotoxic steroidal glycoalkaloids, which significantly reduces tuber quality, increases food safety risks, and leads to rejection by consumers and the processing industry. This review conducts an in-depth analysis of three key aspects: (1) the differences in various light conditions, namely, the disparities in light sources, wavelengths, intensities, and durations; (2) the characteristics of potato cultivars resistant to greening; and (3) the molecular mechanisms of light-induced biosynthesis of chlorophyll and steroidal glycoalkaloids (SGAs). This review is expected to provide technical support for potato food safety measures and a theoretical foundation for the molecular breeding of green-resistant potato varieties.

Potato tubers undergo greening and accumulate steroidal glycoalkaloids (SGAs) upon light exposure, posing potential food safety risks. In this study, six potato cultivars (“Favorita”, “Lucinda”, “Jizhangshu 12”, “Longshu 10”, “Qingshu 9”, and “Purple Potato”) were subjected to six light treatments (dark, UVA, blue, green, red, and white), and peel color, pigment content, SGAs, and the expression of genes related to light signaling, chlorophyll biosynthesis, and SGA biosynthesis was evaluated. Under green light, the contents of α-solanine and α-chaconine were 76.22 and 171.84 mg/kg fresh weight (FW), respectively; by contrast, their levels under blue and white light were approximately 60% higher. These effects may be mediated by the upregulation of HY5 and COP1 expression, which in turn could regulate the biosynthesis of chlorophyll-related genes (CHID, CHLI1) and SGA-related genes (HMGR, SGT1). Yellow-skinned cultivars exhibited pronounced light sensitivity (chlorophyll 18.47–18.52 mg/kg FW; SGAs up to 290.41 mg/kg FW), whereas red- and purple-skinned cultivars delayed greening through anthocyanin-mediated light attenuation. Collectively, these findings provide a framework for postharvest management and breeding, suggesting that reducing blue light while enhancing green light in spectral illumination, together with the development of anthocyanin-enriched cultivars, may serve as effective strategies to extend shelf life, mitigate food safety risks, and reduce postharvest losses.