Ethephon-mediated modulation of growth, tuber quality, and anthocyanin biosynthesis in pigmented potatoes (Solanum...

Plant growth regulators can regulate the metabolism of plants, thereby regulating the growth and development of plants. In this paper, the effect mechanism of plant growth regulator ethephon (ETH) on growth parameters, leaf physiological characteristics, and tuber quality traits of pigmented potato (Solanum tuberosum) were investigated. Two pigmented potato varieties, Jianchuanhong and Huaxinyangyu, which are rich in anthocyanins and have distinctive regional characteristics, were considered as the experimental materials, different concentrations of ETH were treated at the beginning flowering stage and the full flowering stage to investigate the optimal application stage and concentration that affect the physiological and biochemical properties of pigmented potatoes. The experiment results showed that the application of 1000 mg/L ETH at the full flowering stage significantly improved stress resistance and tuber quality, which as evidenced by a 2.7-fold and 1.3-fold increase for anthocyanin content in tuber of Jianchuanhong and Huaxinyangyu, respectively. Transcriptomic analysis revealed that these enhancements were driven by a substantial upregulation of key anthocyanin biosynthetic genes (St4CL, StF3H, StUFGT), which increased from 3.0 to 24.8-fold in variety Jianchuanhong and from 2.2 to 7.0-fold in variety Huaxinyangyu, as well as by associated MYB and ERF transcription factors. These findings provide a robust theoretical foundation and practical methodology for using ETH to improve pigmented potato cultivation.