Physiological Response And Mechanism Of Pigment Potato To Low Temperature

Yunnan belongs to the low-latitude plateau monsoon-type three-dimensional climate,and the temperature varies significantly vertically with the height of the terrain.Potatoes originated in the Andes Mountains of South America and formed an adaptation to the cool climate,and the suitable temperature for growth is 10-23 °C.Yunnan and it’s unique climatic conditions make it possible to grow potatoes year-round.According to the suitable temperature for potato growth,it is divided into a potato area in spring,two seasons in spring and autumn,and a potato area in winter.The production practice experience found that the color of the same pigment potato variety in the same season,the color of the pigment potato planted at high altitude was obviously darker than that of the medium and low altitude.For example,the color of the local red potato variety Jianchuanhong planted in the alpine mountainous area of Jianchuan County,Dali,Yunnan,is obviously darker than that of Kunming,and it is believed that it is caused by the strong light in the high-altitude area.However,the dam area of the potato planting area in spring and autumn is shady in autumn,and the light intensity is weaker than that in spring and summer.The color of autumn-sown potatoes is darker than that of spring-sown potatoes,which is inconsistent with the theory that light is the key environmental factor affecting anthocyanin synthesis.Compared with the dam area,the alpine mountain area has stronger sunlight and lower temperature.It is speculated that low temperature has an important stimulating effect on the synthesis of pigment potato anthocyanins.Therefore,studying the molecular mechanism by which low temperature affects the accumulation of anthocyanins in pigment potato has important guiding significance for cultivating widely suitable and excellent pigment potato varieties and selecting a suitable cultivation environment.In this study,the Yunnan local characteristic pigment potato varieties Jianchuanhong and Huaxinyangyu were used as test materials to preliminarily determine the effects of different temperature treatments on potato growth and tuber nutrients,especially anthocyanin accumulation,and to explore the key transcription factors affecting anthocyanin synthesis in pigment potato tubers.Factors and structural genes provide a theoretical basis and technical guidance for the selection of the planting environment of pigment potato varieties and the formulation of cultivation measures.The main research results are as follows:1.We investigated the physiological responses of Jianchuanhong and Huaxinyangyu after experiencing appropriate low temperatures(15 °C and 10 °C)during the whole growth period.The results showed that the two different low-temperature treatments significantly inhibited the growth of the aerial parts of the plant,significantly increased the enzyme activities related to leaf stress resistance,and increased the ratio of roots to shoots.The low-temperature treatment at 15 °C significantly improved the yield and quality of tubers,especially the flower color.The content of antioxidant compounds such as glycosides increased significantly,while the low-temperature treatment at 10 °C resulted in the failure of potato formation in Huaxinyangyu and the small tuber of Jianchuanhong and no accumulation of pigment,which proved that the low-temperature treatment was not conducive to the growth of primary and secondary potato products.accumulate.2.On the basis of the above experimental results,the treatment and period with the highest anthocyanin content were selected for transcriptome sequencing.The results showed that the structural genes of anthocyanin synthesis,such as St ANS,St UFGT,St DFR,St F3’H,St PAL and St CHS,were upregulated at 15 °C,and three transcription factors,StMYB113,StMYB308 and StbHLH93,were also upregulated.Low-temperature treatment may promote the accumulation of anthocyanins by increasing the relative expression of structural genes and transcription factors involved in anthocyanin synthesis.The temporal and spatial changes in the gene relative expression of the StMYB113,StMYB308 and StbHLH93 genes in different periods were found to be in the same organization as in the same period.The content of anthocyanins in the samples showed a significant positive correlation.It was speculated that StMYB113,StMYB308 and StbHLH93 could respond to low temperature and regulate the synthesis of anthocyanins.3.Then,the three transcription factors StMYB113,StMYB308 and StbHLH93 screened were cloned and analyzed by bioinformatics,and it was found that StMYB113 has only one MYB domain,StMYB308 has two MYB domains,which are R2R3-MYB transcription factors,and StbHLH93 has one MYB domain.The HLH domain and StMYB113,StMYB308 and StbHLH93 are all similar to Arabidopsis thaliana and low temperature and anthocyanin synthesis families in the evolutionary tree;the subcellular localization of StMYB113,StMYB308 and StbHLH93 genes are all in the nucleus,and they are nuclear transcription factors.Nuclear transcriptional regulatory activity.4.The overexpressed StMYB113,StMYB308 and StbHLH93 genes were transferred into the leaves of safflower Dajinyuan.It was observed that the leaves overexpressing StMYB308 and StbHLH93 had obvious pigment accumulation.The bimolecular fluorescence complementary experiment confirms that StMYB308 and StbHLH93 can form an interacting protein.q-RT-PCR proved that the relative expression of endogenous transcription factors Nt AN1 a and Nt AN1 b related to anthocyanin synthesis were significantly increased in transgenic tobacco.It is speculated that StMYB308 and StbHLH93 regulate the synthesis of anthocyanins through interaction.