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采用RT-PCR和RACE技术从杜梨(Pyrus betulifolia)根系中克隆得到1个质膜内在蛋白(plasma membrane intrinsic proteins,PIPs)类的水孔蛋白基因全长c DNA序列,命名为Pb PIP1。该基因全长为1 297 bp,包含1个870 bp的完整开放阅读框,编码289个氨基酸。氨基酸序列分析表明,Pb PIP1含有水孔蛋白家族高度保守的2个天冬酰胺-哺氨酸-丙氨酸基序(Asn-Pro-Ala,NPA)基序和6个跨膜区,并具有高等植物特有的PIPs高度保守序列。聚类分析表明该基因编码蛋白属于PIP1亚家族。基因表达分析结果表明,Pb PIP1在杜梨根、茎、叶中均有表达,在根中表达量最高,茎中最少。20%PEG处理时,该基因在杜梨根系中的表达水平随胁迫时间的延长先上升后降低;但在4°C低温、100 mmol·L~(-1) Na Cl处理时该基因的表达水平差异不明显。这说明Pb PIP1可能主要在杜梨根系中发挥作用,其表达丰度可能与杜梨的抗旱性密切相关。
The full length c DNA sequence of aquaporin gene was cloned from Pyrus betulifolia root by RT-PCR and RACE techniques and named as Pb PIP1. The gene was 1 297 bp in length and contained a complete 870 bp ORF encoding 289 amino acids. Amino acid sequence analysis showed that Pb PIP1 contains two asparagine-alanine-alanine motif (NPA) motifs and six transmembrane domains that are highly conserved in aquaporin and has Higher plant-specific PIPs are highly conserved sequences. Cluster analysis showed that the gene encoded protein belongs to the PIP1 subfamily. The results of gene expression analysis showed that Pb PIP1 was expressed in the roots, stems and leaves of Pear, and the expression was the highest in roots and the least in stems. When treated with 20% PEG, the expression level of this gene increased firstly and then decreased with the prolongation of stress time in Pyrus pyrifolia. However, the expression of this gene at 4 ° C and 100 mmol·L -1 NaCl The difference is not obvious. This indicates that Pb PIP1 may play a major role in the root system of Petiole, and its abundance may be closely related to the drought resistance of Pear.