Recently, a research paper titled “A freezing responsive UDP-glycosyltransferase improves potato freezing tolerance via modifying flavonoid metabolism” was published online in Horticultural Plant Journal (a top-tier journal in the field of agricultural and forestry sciences, ranked in the 1st district by the Chinese Academy of Sciences) by the team of Zhu Guangtao at the School of Life Sciences, Yunnan Normal University. The paper cites the Jiupo BPC500H Growth Chamber and reveals that ScUGT73B4 specifically responds to frost stress and regulates the accumulation of flavonoids, thereby enhancing potato freezing tolerance by increasing reactive oxygen species scavenging ability.
Potato (Solanum tuberosum) is an important staple crop globally, providing a significant source of carbohydrates and nutrients to humans. Cultivated potatoes are highly sensitive to low-temperature frost stress, which is a major abiotic stress factor in potato production. Once frost damage occurs, yield losses are severe. However, several wild potato varieties, such as S. commersonii, exhibit strong cold resistance, offering valuable resources for frost resistance gene mining and cold-resistant potato breeding. Through metabolomic and transcriptomic association analysis, key metabolic pathways and core genes involved in frost response in S. commersonii were identified, and the mechanism by which ScUGT73B4 regulates cold tolerance in wild potatoes was elucidated, with its potential application in cold-resistant potato breeding explored.
Flavonoids exhibit distinct clustering patterns under low-temperature stress in DM (sensitive) and CM (cold-resistant) varieties. Several glycosylated flavonoids of quercetin and kaempferol at the 3-O or 7-O position were significantly upregulated at 6 and 12 hours of cold stress in CM, with levels significantly higher than in DM. Transcript-metabolite association analysis revealed that the expression of 8 UGTs was strongly correlated with these glycosylated flavonoids, with UGT73B4 being significantly induced under cold stress specifically in CM (Figure 1).
Figure 1:Cold stress promotes the transcription of ScUGT73B4 and the accumulation of glycosylated flavonoids in CM.
Phenotypic analysis of transgenic potatoes showed that overexpression of ScUGT73B4 enhanced the freezing tolerance of cultivated varieties (Figure 2). ScUGT73B4 promotes the accumulation of glycosylated flavonoids under cold conditions, which enhances the antioxidant capacity of potato leaves under low-temperature stress. Further studies indicated that foliar application of flavonoids significantly improved the cold tolerance of cultivated potatoes. This research lays the theoretical foundation for utilizing wild potato resources and improving frost-resistant varieties.
Figure 2: Overexpression of ScUGT73B4 enhances freezing tolerance in cultivated potatoes.
Yunnan Normal University PhD student Bao Huihui and Associate Researcher Yuan Li from the Shenzhen Agricultural Genomics Institute of the Chinese Academy of Agricultural Sciences are the first authors of this paper, with Professor Zhu Guangtao from the Potato Science Research Institute, Yunnan Normal University, serving as the corresponding author. This research was funded by the National Natural Science Foundation of China (U2002204 and 32272725), the National Key R&D Program (2022YFF1002500), and other projects.