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羊草具有耐寒、耐盐和耐旱等特点,是一种兼具经济价值和生态价值的多年生重要牧草。脯氨酸是植物在渗透胁迫下积累的主要渗透调节物质之一。Δ1-吡咯啉-5-羧酸合成酶(P5CS)是脯氨酸的谷氨酸合成途径中的关键酶。根据前期Solexa测序结果的数据,设计同源引物,从羊草中克隆了一个P5CS基因,该基因cDNA序列全长2 197bp,推断其编码730个氨基酸,根据序列比对将其蛋白命名为LcP5CS1。同源性分析表明:LcP5CS1与单子叶植物短柄草P5CS的同源性为95%,而与双子叶植物的P5CS同源性较低。表达模式分析表明,在叶鞘、叶和茎中,LcP5CS1均有较高表达;在冷、ABA、盐和干旱胁迫下,该基因明显受胁迫诱导,并随胁迫时间的延长,其表达量总体呈上调趋势。对羊草人工创伤处理后的Solexa测序差异表达数据分析表明:LcP5CS1在处理2和6h后表达量明显提高,推测羊草创伤处理后体内脯氨酸含量升高可能是其耐牧的一种适应性机制。
Leymus chinensis has the characteristics of cold tolerance, salt tolerance and drought tolerance, and is a perennial important grass that has both economic value and ecological value. Proline is one of the major osmolytes accumulated by plants under osmotic stress. The 1-pyrroline-5-carboxylic acid synthase (P5CS) is a key enzyme in the glutamate synthesis pathway of proline. According to the data of previous Solexa sequencing, a homologous primer was designed and a P5CS gene was cloned from Leymus chinensis. The cDNA sequence of this gene was 2 197 bp in length, which deduced that it encoded 730 amino acids. The protein was named LcP5CS1 by sequence alignment. Homology analysis showed that LcP5CS1 shared 95% homology with P5CS of monocotyledon and low homology with P5CS of dicotyledon. Expression pattern analysis showed that LcP5CS1 was highly expressed in leaf sheath, leaf and stem. Under cold, ABA, salt and drought stress, the gene was significantly induced by stress, and with the prolonging of stress time, the expression level of LcP5CS1 was generally Up trend. The differential expression data of Solexa after artificial trauma treatment of Leymus chinensis showed that the expression of LcP5CS1 was significantly increased after 2 and 6 hours of treatment, suggesting that the increase of proline content after the treatment of Leymus chinensis injury may be an adaptation of its resistance to grazing Sexual mechanisms.