甘蔗Δ~1-吡咯啉-5-羧酸合成酶(ScP5CS)基因分离及其分析(英文)

Isolation and characterization of a gene encoding the Δ~1-pyrroline-5-carboxylate synthetase in sugar (Saccharum officinarum L.)

以甘蔗品种ROC22为材料,待甘蔗生长至4～5叶期直接以25%PEG6000淋灌根部模拟水分胁迫。采用同源克隆与RT-PCR法从甘蔗叶片中得到甘蔗Δ1-吡咯啉-5-羧酸合成酶(Saccharum officinarum L.Δ1-pyrroline-5-carboxy-late synthetase,ScP5CS)基因的编码区cDNA序列,其长度为2151 bp,为一个完整的ORF,编码716个氨基酸,GenBank注册号为EU005373。核苷酸序列与前人已注册的甘蔗P5CS(EF155655)相比,同源率达到98%,但推断编码的氨基酸同源率仅为92%。该基因具有P5CS共有的结构域与结合位点:Putative ATP-binding site;Putative leucine domains;Glu-5-kinase domain;Putative NADPH-binding domain;Conserved GSA-DH domain保守区,脯氨酸反馈抑制作用位点。与前人已注册的甘蔗P5CS基因氨基酸序列(ABM30223)比较,在γ-GK保守域(Glu-5-kinase domain)内氨基酸变化较大,而与水稻、小麦的相比,其变化较小。因此,推断为甘蔗P5CS基因家族中的一个新成员。

Sugarcane variety ROC22 was used as the experimental material, and the water stress treatment was performed for the 4 or 5-leafed plants with 25% polyethylene glycol （PEG） 6000 solutions. The eDNA sequence of ScPSCS gene in sugarcane with 2151 bp in length was isolated by homologous cloning, which contained an open reading frame encoding a protein of 716 amino acids, with GenBank accession number EU005373. Comparing the sequence of ScPSCS with that of sugarcane PSCS reported in GenBank, the nucleotide acid showed high identity（98%）, but the deduced amino acid was only 92%. The deduced protein contains putative ATP-binding site, putative leucine domains, Glu-5-kinase domain, putative NADPH-binding domain, conserved GSA-DH domain and feedback inhibition site. Besides, there were more differences in Glu-5-kinase domain from the deduced amino acid of sugarcane PSCS reported （ABM30223）, but less for the PSCSs from rice （Oryza sativa） and wheat （Triticum aestivum）. So it is confirmed this gene is a new gene of sugarcane P5CS.