Screening and functional analysis of StMYB transcription factors in pigmented potato under low-temperature treatment.

MYB transcription factors play an extremely important regulatory role in plant responses to stress and anthocyanin synthesis. Cloning of potato StMYB-related genes can provide a theoretical basis for the genetic improvement of pigmented potatoes. In this study, two MYB transcription factors, StMYB113 and StMYB308, possibly related to anthocyanin synthesis, were screened under low-temperature conditions based on the low-temperature-responsive potato StMYB genes family analysis obtained by transcriptome sequencing. By analyzed the protein properties and promoters of StMYB113 and StMYB308 and their relative expression levels at different low-temperature treatment periods, it is speculated that StMYB113 and StMYB308 can be expressed in response to low temperature and can promote anthocyanin synthesis. The overexpression vectors of StMYB113 and StMYB308 were constructed for transient transformation tobacco. Color changes were observed, and the expression levels of the structural genes of tobacco anthocyanin synthesis were determined. The results showed that StMYB113 lacking the complete MYB domain could not promote the accumulation of tobacco anthocyanins, while StMYB308 could significantly promote the accumulation involved in tobacco anthocyanins. This study provides a theoretical reference for further study of the mechanism of StMYB113 and StMYB308 transcription factors in potato anthocyanin synthesis.

Effects of appropriate low-temperature treatment on the yield and quality of pigmented potato (Solanum tuberosum L.) tubers.

Temperature is one of the important environmental factors affecting plant growth, yield and quality. Moreover, appropriately low temperature is also beneficial for tuber coloration. The red potato variety Jianchuanhong, whose tuber color is susceptible to temperature, and the purple potato variety Huaxinyangyu, whose tuber color is stable, were used as experimental materials and subjected to 20 °C (control check), 15 °C and 10 °C treatments during the whole growth period. The effects of temperature treatment on the phenotype, the expression levels of structural genes related to anthocyanins and the correlations of each indicator were analyzed. The results showed that treatment at 10 °C significantly inhibited the potato plant height, and the chlorophyll content and photosynthetic parameters in the leaves were reduced, and the enzyme activities of SOD and POD were significantly increased, all indicating that the leaves were damaged. Treatment at 10 °C also affected the tuberization of Huaxinyangyu and reduced the tuberization and coloring of Jianchuanhong, while treatment at 15 °C significantly increased the stem diameter, root-to-shoot ratio, yield and content of secondary metabolites, especially anthocyanins. Similarly, the expression of structural genes were enhanced in two pigmented potatoes under low-temperature treatment conditions. In short, proper low temperature can not only increase yield but also enhance secondary metabolites production. Previous studies have not focused on the effects of appropriate low-temperature treatment during the whole growth period of potato on the changes in metabolites during tuber growth and development, these results can provide a theoretical basis and technical guidance for the selection of pigmented potatoes with better nutritional quality planting environment and the formulation of cultivation measures.