尖萼耧斗菜UGT基因家族成员鉴定及表达分析

Identification and expression analysis of UGT gene members in Aquilegia oxysepala

【目的】明确尖萼耧斗菜和黄花尖萼耧斗菜中UGT家族成员的结构特性,挖掘合成花青素的关键UGT基因。【方法】基于尖萼耧斗菜花色转录组,筛选与鉴定UGT家族基因成员并分析其理化性质、保守基序、系统进化和顺式作用元件等,结合UGT基因在2种尖萼耧斗菜萼片中不同时期的表达模式,筛选出合成花青素的候选基因。【结果】共鉴定出154个AoUGT基因成员,编码蛋白质含有52~1293个氨基酸,相对分子量为5.897~144.174 kDa,其理论等电点范围为3.21~7.14之间,偏酸性蛋白较多,均为亲水性蛋白;二级结构以α-螺旋和无规则卷曲为主,均具有UGT保守结构域。尖萼耧斗菜UGT基因家族成员共分为14个亚家族,A组UGT基因成员数量最多,G和J组的UGT基因成员数量最少。MEME保守基序分析显示UGT基因家族均含有2个高度保守的基序Motif 1和Motif 4,这2个保守基序共同组成UGT基因家族的PSPG保守结构域。启动子顺式作用元件分析发现,AoUGT家族成员启动子的顺式作用元件涉及光响应、激素、胁迫及MYB结合位点等。AoUGT147/127/45/143在尖萼耧斗菜的开花前期(S2)中处于高表达水平,而在黄花尖萼耧斗菜中始终处于低表达水平。【结论】AoUGT147/127/45/143是尖萼耧斗菜花色差异的关键基因,在花色的形成过程中发挥重要作用,为后续花色研究提供了重要线索。

【Objective】The present paper aimed to reveal the structural characteristics of UGT family members in Aquilegia oxysepala and A.oxysepala f.pallidiflora,and screen the key UGT genes for anthocyanin biosynthesis.【Method】Based on previous floral color transcriptome of A.oxysepala and A.oxysepala f.pallidiflora,members of UGT family were selected and identified.Their physicochemical properties,conserved motifs,phylogenetic evolution and cis⁃acting elements were analyzed.Combining with expression patterns of UGT genes in the sepals of two A.oxysepala species at different periods,candidate genes for anthocyanin synthesis were screened out.【Result】A total of 154 AoUGT gene mem⁃bers were identified.Their encoded proteins contained 52-1293 amino acids,relative molecular weight was 5.897-144.174 kDa,theoreti⁃cal isoelectric points were 3.21-7.14,and most of proteins were acidic and hydrophilic.The secondary structures were dominated byα⁃helix and random crimp,both of which had UGT domains.The UGT gene family members of A.oxysepala were divided into 14 subfamilies.The number of UGT gene members in group A was the largest,and the number of UGT gene members in group G and group J was the least.MEME conserved motif analysis showed that the UGT gene family contained two highly conserved motifs Motif 1 and Motif 4,which together formed the PSPG conserved domain of the UGT gene family.The analysis of cis⁃acting elements of promoter showed that the promoter regions of AoUGT family members involved in light responsive,hormone responsive,stress responsive and flavonoid MYB binding sites.According to ex⁃pression patterns and cognate relationship,AoUGT147/127/45/143 significantly increased during pre⁃flowering period in A.oxysepala,howev⁃er,these gene expressions were continuously sustained at low levels in A.oxysepala f.pallidiflora.Therefore,these members played important roles during floral color variation,which were determined to be candidate genes.【Conclusion】AoUGT147/127/45/143 are key genes for flower color variation in A.oxysepala and play an important role in the formation of flower color.