Study On The Regulatory Function Of PdMYB113 And PdMYB111 Of Populus Deltoids Cv.zhonghua Hongye In The Phenylpropane Pathway

Compared with the green garden landscape plants with single color,the colorful-leaf plants are more and more popular.In the future,the cultivation of urban garden plants will tend to be diversified,including not only the diversification of plant varieties but also the diversification of plant colors.The colorful-leaf plants greatly enrich the urban garden landscape level,create a good visual effect,and have high ornamental value and broad development prospects.Anthocyanins are the main flavonoid compounds involved in the formation of plant flower color and fruit color,and changes in their content can directly cause changes in plant leaf color.It was known that MYB,b HLH and WD40 transcription factors could form a complex to coordinate the accumulation of anthocyanins.In recent years,there have been more and more reports about MYB transcription factors involved in regulating anthocyanin biosynthesis,but there are relatively few reports about MYB transcription factors regulating anthocyanin synthesis in woody plants,especially poplars,thereby affecting leaf color.Based on the screening work,this study explored whether the key transcription factors Pd MYB111 and Pd MYB113 of Populus ’Zhonghua Hongye’ could regulate the synthesis of anthocyanins in the phenylpropane flavonoid pathway,and identified the Pd MYB113 gene has a greater contribution to leaf color.I hope to use this gene to breed new varieties of colorful-leaf plants,and lay a foundation for enriching the material resources of colorful-leaf plants.(1)The L~*a~*b~* value of Populus deltoides cv.Zhonglin 2025 and its bud varieties,P.deltoides cv.Quanhong and P.deltoides cv.Lianghong were determined by NF333 colorimeter and the anthocyanin content was determined.The results show that the red intensity of Quanhong and Lianghong leaves is greater than that of the Zhonglin 2025 leaves.In addition,the anthocyanin content in the leaves of the Quanhong and Lianghong significantly increased compared to Zhonglin2025.It is speculated that the increase of anthocyanin content is the main reason for the red leaves of Quanhong and Lianghong.The above results provide ideas for subsequent experiments.(2)Pd MYB113、Pd MYB111、Pd GL3、Pd EGL1 and Pdb HLH42-like,which have relatively high expression levels in the middle and top leaves of Quanhong and Lianghong were selected from the second-generation transcriptome sequencing data.It was found that Pd MYB113 protein could interact with Pd GL3 protein by the yeast two-hybrid technology(Y2H).It is speculated that Pd MYB113 and Pd GL3 may interact to regulate anthocyanin biosynthesis pathway,but Pd MYB111 cannot interact with the candidate interaction proteins b HLH.(3)Through genetic transformation experiments,22 Nicotiana tabacum Pd MYB113 transgenic lines and 9 Nicotiana tabacum Pd MYB111 transgenic lines were obtained;5 poplar Pd MYB113 transgenic lines and 4 poplar Pd MYB111 transgenic lines were obtained.The results showed that some Pd MYB113 transgenic Nicotiana tabacum lines showed purple-red in the veins,and even some leaves showed the characteristics of chlorosis.The roots of Pd MYB113 transgenic poplar showed dark pink,and the leaves and stems showed varying degrees of purple-red.The colorful-leaf plants with stable expression were obtained.Pd MYB111 transgenic plants showed no color changes in roots,stems,leaves and other tissues.This provides more clues that are new and material background for further research on whether MYB transcription factors can regulate the production of anthocyanins and even lignin and other secondary metabolites in the plant phenylpropane pathway.(4)NF333 colorimeter was used to measure the L*a*b* value of 84 K and Pd MYB113 transgenic poplar leaves.The results showed that the red intensity of transgenic leaves was much higher than that of 84 K wild-type leaves.Moreover,compared with 84 K,the expression levels of the structural gene CHS、CHI、FLS/F3H、DFR and ANS in anthocyanin regulation pathway of Pd MYB113 transgenic poplar were significantly up-regulated.It is speculated that overexpression of Pd MYB113 can increase the expression of structural genes in anthocyanin regulatory pathway,thereby increasing the anthocyanin content of plants,and finally forming colorful-leaf plants.