中文摘要：

苯丙氨酸解氨酶（PAL）是植物木质素生物合成途径中的关键酶,参与木质素、类黄酮和花青素等次生代谢产物的形成。本研究以‘N51’象草（Pennisetum purpureum）为材料,通过同源克隆、3′RACE和hi-Tail PCR的方法,对PAL基因进行克隆,得到PpPALcDNA序列2429bp以及DNA序列全长3907bp。PpPAL编码的蛋白包含720个氨基酸,具有典型的GTITASGDLVPLSYIAG苯丙氨酸解氨酶保守活性基序。运用生物信息学进行分析,PpPAL基因cDNA序列与玉米（Zea mays L.）ZmPAL的相似性最高为94%,与其他禾本科植物也有着较高的相似性。在氨基酸序列系统进化分析中,PpPAL与ZmPAL遗传距离最近,并与其他禾本科植物PAL聚为一类。PpPAL蛋白的三维结构模型显示,PpPAL蛋白具有典型的＂海马状＂结构,表明PpPAL是典型的苯丙氨酸解氨酶家族,对木质素的合成起着重要的作用。

英文摘要：

Phenylalanine ammonia-lyase（PAL）is a key enzyme involved in lignin biosynthesis.It catalyzes the first step of phenylpropanoid pathway,which supplies precursors for a variety of secondary metabolites including phenolics,flavonoids and anthocyanin.In this study we isolated a PALgene fromPennisetum purpureumcv.N51 using homology cloning and RACE（Rapid Amplification of cDNA Ends）methods as well as hi-Tail PCR.The length of PpPALcDNA sequence was 2429 bp.The nucleotide sequence of PpPALgene was 3907 bp long and high similarity to ZmPAL,with 94%identity.The PpPALgene encoded a 720-amino-acid protein,which contained a conserved motif of GTITASGDLVPLSYIAG.In phylogenetic tree,the PpPALhad a close genetic distance with ZmPAL,and was clustered in the same group with other gramineous plants involved in lignin biosynthesis.By predicting,the three-dimensional structure of the PpPALprotein showed a typical ＂sea horse＂ shape,which indicated that PpPALis a typical family member of phenylalanine ammonia-lyase,should play an important role in lignin synthesis.