Analysis Of Physiological And Biochemical Factors And Related Gene Expression In The Color Presentation Of Lagerstroemia Indica Flowers

Lagerstroemia indica is an important summer ornamental plant in China,also known as the Hundred Day Red or Purple Blossom.It is a deciduous shrub or small tree.Although crape myrtle has a wide variety and rich colors,the common colors are mainly purple and red.However,in order to meet the needs of different environments and occasions,cultivating new varieties is of great significance.This study selected 14 different varieties of crape myrtle and measured their flower color,petal vacuole environment,nutrients,and pigment content.At the same time,qRT PCR was used to analyze the genes related to flower color,comprehensively analyzing the impact of various indicators on crape myrtle flower color,and exploring the reasons why crape myrtle presents different flower colors,which helps to deeply understand the synthesis mechanism of crape myrtle flower pigments.In addition,this study also explored the role of LiUFGT gene in the biosynthesis of anthocyanin in crape myrtle,providing valuable scientific basis for the improvement of crape myrtle flower color research.The main research findings are as follows:(1)According to the RSHCC colorimetric results,14 crape myrtle varieties can be divided into purple,red,pink,white,and multicolor systems.The brightness L*value of the white color system is the highest,while the values of the red and purple colors are the lowest,indicating that the darker the color,the lower the brightness value.The white color has the lowest redness a*value,indicating a small amount of anthocyanin.The yellowness b*value of the red color system is the highest,while the purple color system is the lowest and negative.(2)The pH value of the petal cell fluid of crape myrtle is between 3.59 and 4.11,and the lower the value,the darker the flower color.The cell moisture content ranges from 73%to 81%,and there is no significant difference between different color systems.The soluble protein content varies significantly among different color systems,with the purple system having the lowest content and the red and pink systems having the highest content,which may be one of the factors contributing to the difference in flower color.There is no significant difference in soluble sugar content among different varieties,indicating that its impact on flower color may be influenced by other factors.The content of anthocyanin is the main reason for the difference in flower color of crape myrtle.Total total flavonoids and carotenoid are auxiliary pigments,and varieties with darker flower colors have higher anthocyanin content and richer components.(3)The expression levels of LiCHS,LiANS,LiF3’H,and LiUFGT genes are highest in the red line,while the expression levels of LiCHI,LiF3H,and LiF3’5’H genes are highest in the purple line.Correlation analysis found a significant positive correlation between anthocyanin content and the expression of LiANS and LiF3’H genes,indicating that LiANS and LiF3’H genes contribute to anthocyanin accumulation.(4)The open reading frame length of the LiUFGT gene in crape myrtle is 1431 bp,encoding 476 amino acids,with a relative molecular weight of 52465.22 Da and a theoretical isoelectric point of 5.66.LiUFGT protein α-Spiral and irregular curls are mainly unstable hydrophobic proteins.After multiple sequence alignment,it was found that the similarity between LiUFGT protein and pomegranate was the highest,at 68.70%;System evolution analysis shows that the LiUFGT protein has the closest genetic relationship with poplar,pomegranate,and summer oak,and the farthest genetic relationship with mountain jute and soil bottle grass.