2C型丝氨酸/苏氨酸蛋白磷酸酶(PP2C)是植物体内脱落酸ABA信号传导关键负调控酶,在植物耐非生物胁迫中发挥着重要的作用。本研究利用RT-PCR技术,克隆出编码杜梨PP2C蛋白的基因PbPP2C,其核苷酸序列全长1353 bp,开放阅读框长1263 bp,编码422个氨基酸残基,这些残基中包括了与二价金属离子结合的MED、DGH、DG和D结构域。系统发生分析结果表明,该氨基酸与拟南芥AHG3亲缘关系最近。实时荧光定量PCR分析结果表明：盐胁迫条件下,PbPP2C基因在根、茎、叶中的表达12 h达到峰值,同时在根中72 h达到第二个峰值；干旱胁迫条件下,PbPP2C基因在根、茎、叶中表达72 h达到峰值。说明PbPP2C与杜梨耐盐和耐干旱胁迫存在紧密关联。%Protein phosphatase PP2C is an important negative regu1ator and exerts crucia1 ro1es when p1ants are in abiotic stress. The cDNA of PbPP2C encoding protein phosphatase PP2C was c1oned by RT-PCR from sa1t-to1erant Pyrus betulaefolia Bunge. The 1ength of nuc1eotide sequence was 1 353 bp in 1ength with a 1 263 bp ORF ( open reading frame) , encoding 422 amino acids, which inc1uded meta1 ions-binding domain such as MED, DGH, DG and D amino acid resi-dues. Phy1ogenetic tree showed that PbPP2C was c1ustered c1ose1y with AHG3 of Arabidopsis. The resu1ts by qRT-PCR sug-gested that the expression of PbPP2C in roots, tems and 1eaf of pear achieved the peak at 12-h sa1t stress and the second peak at 72 h in roots. Under drought stress, the expression of PbPP2C in roots, stems and 1eaf of pear reached the peak at 72 h. It is suggested that the PbPP2C gene is c1ose1y re1ated to sa1t to1erance and drought to1erance of Pyrus betulaefolia Bunge.
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