从芹菜(Apium graveolens Linn.)品种‘津南实芹’(‘Jinnanshiqin’)和‘美国西芹’(‘Meiguoxiqin’)中分别克隆获得泛变应原基因 Api g 4;2 个品种的 Api g 4 基因均包含 1 个长度为 405 bp 的开放阅读框,二者间有 3 个核苷酸位点的差异。 2 个品种的 Api g 4 基因均能编码 134 个氨基酸,但二者编码的氨基酸序列有 2 个位点的差异。 多重比对以及进化树分析结果均表明:2 个芹菜品种 Api g 4 基因编码的氨基酸序列与其他植物的泛变应原氨基酸序列同源性较高,氨基酸序列高度保守;与同科植物欧芹[Petroselinum crispum ( Miller) Nyman ex A. W. Hill]和胡萝卜(Daucus carota Linn.)的泛变应原氨基酸序列的同源性均达到 90% 以上,在进化树上也归为同一支。 2 个品种的泛变应原 Api g 4 均为疏水性蛋白,具有相似的三维空间结构,均包含 3 个 α 螺旋和 7 个 β 折叠。 实时定量 PCR 分析结果显示:Api g 4 基因在‘津南实芹’和‘美国西芹’根中的表达水平均最高,在茎和茎尖分生组织中的表达水平相对较低,在叶中的表达水平很弱,且 2 个品种间同一组织的 Api g 4 基因表达水平也有差异,表明 Api g 4 基因的表达具有明显的组织特异性。

Panallergen Api g 4 gene was cloned from two cultivars ‘Jinnanshiqin’and ‘Meiguoxiqin’of Apium graveolens Linn., respectively, and Api g 4 gene of two cultivars contains an open reading frame. with the length of 405 bp, which exists the difference of three nucleotide sites and can encode 134 amino acids but the amino acid sequences encoded by both exist the difference with two amino acids. The analysis results of alignment and phylogenetic tree show that the amino acid sequences encoded by Api g 4 gene from two cultivars and those of panallergens from other plants are highly homologous and are highly conserved. Homology of the amino acid sequences encoded by Api g 4 gene from two cultivars and those of panallergens from same family species Petroselinum crispum (Miller) Nyman ex A. W. Hill and Daucus carota Linn. is above 90%, and they also are clustered in the same branch in phylogenetic tree. Panallergen Api g 4 of two cultivars are all the hydrophobic protein, which have the similar three-dimensional structure with threeα-helixes and seven β-sheets. The result of quantitative real-time PCR shows that the expression level of Api g 4 gene is the highest in root of ‘ Jinnanshiqin’ and ‘Meiguoxiqin’, relatively lower in their stem and shoot-tip meristem and the weakest in their leaf, and the expression level of Api g 4 gene in same tissue of two cultivar also has the difference, indicating the expression of Api g 4 gene in ‘Jinnanshiqin’and ‘Meiguoxiqin’has an obvious tissue specificity.