摘要
类黄酮-3＇-羟化酶（F3＇H）催化二氢堪非醇生成二氢栎皮黄酮,是花青素合成途径关键酶之一,主要参与决定植物花色、种皮和茎叶着色等性状。利用生物信息学手段对植物类黄酮-3＇-羟化酶基因的序列和进化特征进行系统性分析。基因结构分析表明,植物F3＇H基因外显子数变异范围为2~7,单子叶植物包括2个外显子,绝大多数双子叶与陆生低等植物具有3或4个外显子。蛋白序列分析显示,植物F3＇H蛋白具有13个保守基序,其中10个保守基序与结构域p450相互重叠,其他3个保守基序具有种属特异性。进化分析表明,植物F3＇H蛋白具有4个类群,在GroupⅠ、Ⅱ、Ⅲ、Ⅳ亚群中分别检测到4、6、1、7个正选择位点（P〉0.05）,这些位点主要分布在F3＇H蛋白不规则卷曲区,说明植物F3＇H蛋白主要受控于纯净选择。利用滑动窗口方法发现,5对直系同源基因受到负选择作用,但4对旁系同源基因受到正选择作用,发生适应性进化。试验结果可为进一步研究植物F3＇H基因功能及其关键氨基酸位点提供参考。
F3＇H is one of the key enzymes, that catalyze the hydroxylation reaction of dihydrokaemp-ferol to dihydroquercetin, in anthocyanin biosynthesis pathway. This enzyme usual y involves in the formation of plant flower, seed corx and stem color. Here, a systematic analysis of sequence and evolution of F3＇H genes in the plants was conducted using the in silico method. Analysis of gene structure showed that the number of exons ranged from 2 to 7 in plants. Al the monocot plants shared the two-exon gene structure, and F3＇H genes contained 3 or 4 exons in the eudicot and lower land plants. Protein sequence analysis indi-cated that a total of 13 conserved motifs were identified. Among the 13 motifs, 10 motifs shared the overlap-ping regions with the functional domain p450, but the remaining 3 motifs were genus or species-specific. Phy-logenetic analysis revealed that there were four groups, named as Group I,Ⅱ,Ⅲ, IV, each of which was further used to detect selective pressure at individual site level. This results showed that 4, 6, 1, and 7 positively selected sites （P＆gt;0.05） were identified from Group I-IV, respectively, suggesting that F3＇H proteins was un-der purifying selection. In addition, these sites were distributed on the irregular regions of F3＇H proteins. For homologous gene pairs, sliding windows was used to detect selective pressure, and the results showed that five orthologous gene pairs were under negative selection, but four paralogous gene pairs were under posi-tive selection. These results provide an important clue for further investigation of function of F3＇H genes and their corresponding critical amino acid sites in plants.
出处
《东北农业大学学报》
CAS
CSCD
北大核心
2015年第3期41-49,共9页
Journal of Northeast Agricultural University
基金
周口师范学院2014年高层次人才科研启动经费资助项目(ZKNU2014109)
