橡胶草APX基因家族的全基因组鉴定及表达分析

该研究利用生物信息学方法,在橡胶草(Taraxacum kok-saghyz)全基因组中鉴定出7个TkAPXs基因家族成员,进一步分析发现7个成员中有1对是复制基因(TkAPX4/TkAPX6)。进化分析结果显示,7个基因可分为4个亚组;染色体定位分析表明,TkAPX基因家族成员分布广泛,7个TkAPXs基因位于7条不同的染色体上;亚细胞定位结果表明,TkAPX1、TkAPX3、TkAPX5和TkAPX7定位于细胞质,TkAPX4和TkAPX6定位于质膜,TkAPX2定位于叶绿体。启动子区域顺式作用元件分析结果显示,橡胶草APX基因含有大量的应激反应元件,推测APX基因可能对各种外界刺激和胁迫存在灵敏的应激反应机制。实时荧光定量PCR分析表明,橡胶草7个TkAPXs基因家族成员在花萼、花瓣、花梗中表达量均较低,大多数TkAPXs在根茎叶中的表达水平大于花及胶乳,其中TkAPX1在根和茎中的表达水平最高,推测TkAPX1基因可能在橡胶草生长发育过程中起重要作用。进一步对TkAPXs基因家族在逆境胁迫(冷、热、盐、旱)和激素(乙烯、茉莉酸甲酯)处理下的表达分析显示,TkAPX3在根及叶中的表达水平均较对照有大幅度升高,推测TkAPX3基因可能在橡胶草应答逆境胁迫和激素处理反应过程中起重要作用。

Genome wide Identification and Expression Analysis of APX Gene Family in Taraxacum kok saghyz

In this study, 7 TkAPXs genes were identified in Taraxacum kok saghyz whole genome using bioinformatic methods. Further analysis revealed that 2 genes (TkAPX4/TkAPX6) were replication genes. According to the results of phylogenetic relationships, 7 TkAPX genes were divided into four groups. The chromosomal localization analysis indicated that the 7 TkAPX genes were widely distributed and located on 7 different chromosomes. Subcellular localization results indicated that TkAPX1, TkAPX3, TkAPX5 and TkAPX7 were localized in the cytoplasm, TkAPX4 and TkAPX6 were localized on the plasma membrane, and TkAPX2 was localized in the chloroplast. The analysis of the cis acting element in the promoter region shows that there are a large number of stress response elements in TkAPXs sequence, suggesting that there might be sensitive stress response of TkAPXs to various external stress. Real time quantitative PCR analysis showed that the expression levels of 7 TkAPX genes family members in calyxes, petals and pedicels were low. The expression level of most TkAPXs in roots and leaves was greater than that of flowers and latex. TkAPX1 has the highest expression level in roots and stems, suggesting that it may play an important role in the growth and development of T. kok saghyz. Furthermore, we detected the expression level of TkAPX genes after stress (cold, hot, salt, drought) and hormone (ethylene, methyl jasmonate) treatments. The expression levels of TkAPX3 in roots and leaves increased significantly compared with the control indicated that TkAPX3 may be involved in the stress response and hormone response in T. kok saghyz.