Cloning And Transcriptional Expression Analysis Of Chalcone Reductase Gene In Astragalus Membranaceus (Fisch.) Bunge

Astragalus membranaceus(Fisch.)Bunge is one of the commonly used for nourishing Chinese herbal medicines and is commonly used in traditional Chinese medicine and clinical treatment.Isoflavonoids are important natural organic compounds of Astragalus membranaceus,but their molecular biosynthesis mechanism is not yet clear.The chalcone reductase gene is located in an important position of the phenylpropanol metabolism pathway and its derivative pathway,and is a key gene for the catalytic synthesis of isoflavone compounds.In this paper,the full-length and promoter of the chalcone reductase(AmCHR)gene was cloned from Astragalus membranaceus as the research material,and the differential expression of AmCHR in different organs was studied.Based on the promoter bioinformatics,the transcription of AmCHR by external factors was analyzed.The influence of expression regulation laid a foundation for understanding the biosynthesis mechanism of the isoflavones in Scutellaria baicalensis.In this paper,the CHR gene was cloned from Astragalus membranaceus by RT-PCR and RACE technology for the first time and named as AmCHR.The full-length cDNA sequence and gene were 1171 bp and 1246 bp,respectively,containing three exons and two introns.AmCHR encodes a 318 amino acid polypeptide with a molecular weight of approximately 35.58 and a theoretical isoelectric point pI of 6.26.At the same time qRT-PCR results showed that the expression of AmCHR in different organs was consistent with the content order of different organs of calycosin isoflavone glucoside.The results showed that there was a significant correlation between the expression of AmCHR and the accumulation of lannin,which was positively correlated.To further understand the conditions that influence and control the expression of AmCHR,the flank-unknown sequences used to amplify AmCHR using a chromosome walking technique were used.The AmCHR upstream promoter sequence is 1164 bp and it is named AmCHRP.It has the necessary expression control elements for the promoter structure of eukaryotic genes,and also includes stress response elements,light response elements,and cis-acting regulatory elements.qRT-PCR results showed that low temperature and light induced expression of AmCHR,ABA and JA inhibited the expression of AmCHR,MJ,EBR and drought first downregulated,then upregulated the expression of AmCHR,and GA had no effect.