Abstract:

Cinnamic acid 4-hydroxylase (C4H),a key enzyme in the flavonoid synthesis pathway,plays a crucial role in plant stress resistance.To clarify the bioinformatic functions of the C4H gene family in three medicinal liquorice species (Glycyrrhiza uralensis Fisch.,Glycyrrhiza inflata Bat.,and Glycyrrhiza glabra L.),investigate their expression characteristics under abiotic stress,as well as their relationship with the synthesis and accumulation of liquiritin,we used bioinformatics methods to analyze the C4H gene family members,and combined transcriptome data and RT-qPCR validation to understand their expression under abiotic stress and their relationship with liquiritin content.Results showed that a total of 11 C4H genes were identified in the whole genomes of the three medicinal liquorice species and were named GuC4H1—3,GiC4H1—3,and GgC4H1—5,respectively.These genes were distributed on 2 chromosomes in G.uralensis and G.inflata and on 3 chromosomes in G.glabra.Although the gene members differed in physicochemical properties such as the number of amino acids and isoelectric points,all of them were predicted to be localized in the endoplasmic reticulum and contain a C-terminal heme-binding domain (PFGVGRRSCPG).Expression pattern analysis indicated that the 11 C4H genes were expressed in different tissues of the three medicinal liquorice species,and abiotic stress significantly induced the upregulation of C4H gene expression in the underground parts.Among them,the expression of GgC4H5 was the highest under salt stress for 24 h,which was 1.68 times that of the control group (24 h);the expression of GuC4H3 was the highest under drought stress for 2 h,which was 3.03 times that of the control group (2 h).In addition,moderate abiotic stress significantly increased the liquiritin content in the underground parts of the three liquorice species.Under NaCl stress for 2 h,the increase in liquiritin content in G.inflata was the most significant,which was 2.92 times that of the control group (2 h);under PEG stress for 24 h,the increase in liquiritin content in G.glabra was the most significant,which was 2.31 times that of the control group (24 h).GgC4H5 showed a similar expression trend to liquiritin content under salt stress,while GuC4H2,GuC4H3,GiC4H2,and GiC4H3 showed a similar expression trend to liquiritin content under drought stress.Therefore,these genes are likely to be the key genes involved in the response to abiotic stress and liquiritin synthesis in the underground parts of the three medicinal liquorice species.

Key words: Liquorice, C4H gene family, Bioinformatics ananlysis, Gene family identification, Liquiritin

CLC Number: 

• S567.23