The Research Of CiMYB44 In Chrysanthemum Indicum Regulates Plant Pendulous Characteristics

Chrysanthemum indicum is an important resource plant,It has many medicinal and ornamental value.Pendulous plants are different from erect plants,It is popular with a variety of shapes.MYB transcription factors regulate the synthesis of lignin and participate in the function of phenylpropanoid metabolism,They are important transcription factors involved in the regulation of plant pendulous characteristics.In this study,pendulous plant of transfer CiMYB44 gene tobacco and Chrysanthemum indicum was taken as main research object.Stems cell anatomy was observed,The lignin and cellulose content of transgenic plant were determinated.And analysis transcriptome sequencing of transgenic gene Chrysanthemum indicum.Analyze the differences in related regulatory genes in the metabolic pathway of phenylpropanoids,and then explain the mechanism of their production of pendulous characteristics.The main results are as follows:1.Compared with control WT and EV,the stem of transgenic tobacco showed pendulous growth state and stem diameter becomes smaller in different nodes of transgenic tobacco.Microscopic observation of cell anatomy of the upper,middle and lower parts of wild-type and transgenic tobacco stems,The xylem of the vascular bundle of transgenic tobacco moves to the inside of the stem and the proportion of the middle column portion of the entire stem cross-sectional area is reduced,The distribution range of xylem vascular bundles and lignin content become smaller.Stem strength measurement results show that the hardness and penetration resistance of transgenic tobacco stems are reduced.The lignin and cellulose content of transgenic tobacco stems were significantly lower than EV and WT.Fluorescence quantitative analysis of key enzyme genes for lignin and cellulose synthesis,The results showed that CiMYB44 in Chysanthemum indicum can regulate the expression of key enzyme genes in tobacco lignin and cellulose synthesis.2.Compared with control WT and EV,the stem of transgenic Chrysanthemum indicum showed pendulous growth state and stem diameter becomes smaller in different nodes of transgenic tobacco.Microscopic observation of cell anatomy of wild-type and transgenic Chrysanthemum indicum stems,The proportion of transgenic Chrysanthemum indicum vascular bundles in the whole stem is lower than that of EV and WT,and the width of the xylem is significantly smaller.The hardness and penetration resistance of transgenic Chrysanthemum indicum stalks decreased,and the content of lignin and cellulose decreased significantly.The results of the transgenic Chrysanthemum indicum are consistent with transgenic tobacco.3.Transcriptome sequencing of wild-type wild chrysanthemum(CK)and transgenic CiNMYB44 gene Chrysanthemum indicum(MYB)resulted in a total of 136,735 Unigene.The KEGG database gene function annotation results showed that there were 5 metabolic pathways related to the synthesis of pyrethroids.Plant transcription factors were predicted and annotated to 4386 transcription factors of 68 transcription factor families.Differential analysis screened 2851 up-regulated genes and 2528 down-regulated genes.The DEG involved in the phenylpropanoid biosynthesis pathway,the phenylalanine metabolic pathway,the flavonoid biosynthesis pathwaythe and phenylalanine/tyrosine/tryptophan biosynthesis pathway are 30,12,3,and20 respectively.A total of 40 DEG up-regulated expression,25 DEG down-regulated expression.The HCT of the dehydrogenase gene involved in the phenylpropanoid biosynthesis pathway was down-regulated.AOC3 and 4CL were significantly up-regulated in the phenylalanine metabolic pathway.CHS and HCT were down-regulated in the flavonoid biosynthesis pathway.The results obtained by real-time PCR indicate that the data were reliable.