Response Of Flower Color To Temperature And Analysis Of Flower Color Related Gene Expression In Red-flowered Strawberry

The red-flowered strawberry belongs to the intergeneric hybrid(Fragaria × Potentilla)and is a new member of the strawberry family.It has high ornamental value and economic value,but the influence of temperature on its flower color is rarely reported.In this study,the hybrids of red-flowered strawberry varieties ’Fine Beauty’ and ’Qiaojiaren’ were used as test materials.After treatment at different temperature conditions,the change of flower color was observed,and the change of color value was measured.The pH difference method was used to determine the change.The contents of anthocyanins in the petals of red-flowered strawberry were measured.The related physiological indexes of flower color of red-flowered strawberry and the changes of the color values of petals were analyzed.The real-time fluorescence quantitative analysis was used to analyze the color-related genes of red-flowered strawberry at different temperatures.After the expression level,the response of temperature and the mechanism of the color of red-flowered strawberry flower were clearly established,which laid a theoretical foundation for the garden application,flowering period and flower color regulation of red-flowered strawberry.The main results were as follows:After treatment of two red-flowered strawberry cultivars at different temperatures,the petals were all white or slightly pale pink at 30°C.At this time,the brightness values of the two flowers were higher,and the ‘Fenyun’ color brightness of red-flowered strawberry was excellent.That is,as the temperature increases,the anthocyanin content decreases,the flower color decreases,and the brightness value L* increases.When the temperature is 15° C.,the petals of the two red-flowered strawberries show red or dark red,which means that the anthocyanin accumulation increases,the flower color deepens,and the brightness value L* of the petals decreases,indicating that the brightness value L* and red-flowered strawberry petal anthocyanin The content was negatively correlated,and the content of anthocyanin was significantly positively correlated with the a* value of the red and green parameters,and was also significantly positively correlated with the value of the color parameter C*,indicating that the accumulation of anthocyanins was determined by The degree of pigmentation of the red-flowered strawberry petals;whereas the yellow-blue parameter value b* is not affected by temperature.In this experiment,the anthocyanin content of red-flowered strawberry petals was determined by p H differential method,and the anthocyanins in the petals of red-flowered strawberry were extracted by soaking in 0.2% formic acid in methanol.The results of determination of anthocyanin content in two red-flowered strawberry varieties at different temperatures after treatment were the highest at 15°C.Among them,the anthocyanin content in petals of red-flowered strawberry “Fenyun” was 452.19 μg·g-1.The cultivar ‘Xiaotaohong’ has a content of 536.27 μg·g-1.At this time,the petal has the deepest color and is red or dark red.The anthocyanin content was the lowest at 30°C,66.79 μg·g-1 and 87.92 μg·g-1,respectively,and the petals were slightly pale pink or white.With the increase of temperature,the content of anthocyanin decreased,the change of the content of the anthocyanin was consistent with that of the petal color at different temperatures,and the content of anthocyanin was significantly different after treatment at different temperatures.In this experiment,the activity changes of PAL enzyme in the petals of two red-flowered strawberry lines treated at different temperatures were as follows: when the temperature rose,the activity of PAL enzyme gradually weakened,and the activity was highest at 15°C.The activity was the lowest at 30°C,which was reduced by 61.84% and 68.59% in the petals of ‘Fenyun’,‘Xiaotaohong’ of red-flowered strawberry,respectively.The activity was the highest except at 15°C,and the activity change was gentle at other temperatures.The change trend of the activity of CHI enzyme was similar to that of PAL enzyme,and the activity was the highest at 15°C.at 30°C,the PAL enzyme activities of the two were 12.472 U/gFW and 14.293 U/gFW,respectively,which was less than 1/3 of that of 15°C.The enzyme activity of CHI was also regulated by temperature and involved in the synthesis of anthocyanins.At 25°C and 30°C,the activity of CHI enzyme changed little,that is,the CHI enzyme activity was basically stable at this time,the expression level of CHI gene was correspondingly decreased,and the anthocyanin content was reduced.Soluble sugars are a crucial substrate involved in the synthesis of anthocyanins,and their low content will lead to the lack of substrates in the process of where anthocyanins occur,resulting in their synthesis being blocked.After treatment with different temperature conditions,the highest soluble sugar content was found at 15°C,and between 15°C and 20°C,the soluble sugar content in the superior petal of two red-flowered strawberry varieties was 6.77% and 9.84%,respectively;compared with 25°C and 30°C,the soluble sugar content changes were 9.86% respectively,10.63%,compared with the contents of anthocyanins in the superior petals of two kinds of red-flowered strawberry,it was found that the content of both anthocyanins was not consistent,and the content of soluble sugar was positively correlated with the content of anthocyanin,but the relationship was not significant.The soluble protein content was significantly positively correlated with the activity of phenylalanine dehydrogenase and chalcone isomerase,and the activity of both was greatly affected.After treatment of two red-flowered and strawberry lines under different temperature conditions,it was found that when the temperature was lower,CHS,ANS,DFR and UFTG all had higher expression levels,and gene expression at 15°C was higher than that at 30°C.The amount is more than fifty times higher,ie,when the temperature is low,the gene expression level is very high.At this time,the accumulation of anthocyanins is higher,indicating that CHS,ANS,DFR and UFGT genes are directly involved in the regulation of anthocyanin synthesis,and there was a significant positive correlation between the expression level and temperature,which may be the main structural genes that caused the accumulation of anthocyanins and affected the shade of flowers.