摘要：

肉桂酸4-羟基化酶(C4H)是黄酮类化合物合成途径中的一个关键酶,在植物抗逆过程中发挥着重要作用。为了解3种药用甘草(乌拉尔、胀果和光果甘草)中C4H基因家族的生物信息学功能,探究其在非生物胁迫下的表达特性及与甘草苷积累的关系,利用生物信息学方法对C4H基因家族成员进行分析,同时结合转录组数据和RT-qPCR验证了解其在非生物胁迫下的表达情况及与甘草苷含量之间的关系。结果显示,在3种药用甘草全基因组中共鉴定出11个C4H基因,分别命名为GuC4H1~3、GiC4H1~3和GgC4H1~5。这些基因在乌拉尔和胀果甘草中分布在2条染色体上,而在光果甘草中分布在3条染色体上。各基因成员虽然在氨基酸数、等电点等理化性质上存在差异,但亚细胞预测均定位于内质网,且含有C端血红素结合域(PFGVGRRSCPG)。表达模式分析显示,11个C4H基因在3种药用甘草的不同组织中均有表达,且非生物胁迫可显著诱导地下部分中的C4H基因上调表达。其中,GgC4H5在盐胁迫24 h表达量最高,是对照组(24 h)的1.68倍;GuC4H3在干旱胁迫2 h表达量最高,是对照组(2 h)的3.03倍。此外,适度的非生物胁迫显著提升了3种甘草地下部分的甘草苷含量。NaCl胁迫2 h,胀果甘草中甘草苷含量增加最显著,是对照组(2 h)的2.92倍;PEG胁迫24 h,光果甘草中甘草苷含量增加最显著,是对照组(24 h)的2.31倍。GgC4H5在盐胁迫下表达与甘草苷含量趋势一致,GuC4H2、GuC4H3、GiC4H2和GiC4H3在干旱胁迫下表达与甘草苷含量趋势一致。因此,这些基因可能是3种药用甘草地下部分响应非生物胁迫并参与甘草苷合成的关键基因。

关键词: 甘草, 肉桂酸4-羟基化酶基因家族, 生物信息学分析, 基因家族鉴定, 甘草苷

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

中图分类号: 

• S567.23