目的 克隆珍稀濒危兰科药用植物铁皮石斛蛋白磷酸酶（protein phosphatase，PP）DoPP2C1基因，并进行生物信息学和表达模式分析。方法 采用实时定量PCR（qRT-PCR）和RACE技术获基因全长；利用生物信息学软件预测蛋白的理化性质、结构域和亚细胞定位等分子特性；用DNASTAR 7.0和MEGA 6.0分别进行氨基酸多序列比对和进化关系分析；借助qRT-PCR检测基因表达模式。结果 分离到DoPP2C1基因（GenBank注册号KJ995533），cDNA全长1 221 bp，编码1条由285个氨基酸组成的多肽，相对分子质量31 080，等电点6.18；推定的DoPP2C1氨基酸序列具有植物PP2C蛋白家族保守的1个PP2C结构域（27-285）；该蛋白预测无信号肽或跨膜域，定位在细胞质；DoPP2C1蛋白与多种植物PP2C蛋白一致性较高（56.3%~73.7%），与水稻OsPP2C62、高粱XP_002462907、大麦BAK00362和乌拉尔图小麦EMS47641蛋白等亲缘关系近，聚在PP2C分子进化树的F1分支；DoPP2C1基因具有组织表达特异性，其转录本在石斛根和茎中表达量较高，分别为叶中的7.57倍和1.79倍。结论 获得DoPP2C1基因分子特征，为深入研究该基因在铁皮石斛生长发育、逆境生理以及次级代谢调控中的生物学功能奠定基础。

Objective To isolate and characterize a protein phosphatase (PP) encoding gene DoPP2C1 in a rare endangered medicinal orchid species Dendrobium officinale, followed by bioinformatics analysis and expression pattern detection. Methods qRT-PCR and RACE technologies were used to isolate the full length cDNA of DoPP2C1. Characteristics of physiochemical properties, conserved domains, and subcellular localization of DoPP2C1 protein were determined using a series of bioinformatics tools. The analyses of multiple alignment and phylogenetic tree were performed using DNASTAR 7.0 and MEGA 6.0 softwares, respectively. Quantitative PCR was used for gene expression analysis. Results The full length cDNA of DoPP2C1 (GenBank accession KJ995533) was 1 221 bp in length, and encoded a 285-aa protein with a molecular weight of 31 080 and an isoelectric point of 6.18; The deduced DoPP2C1 protein had one PP2C domain (27-285), which are all conserved among the PP2C proteins. DoPP2C1 protein did not contain a signal peptide or a transmembrane region, and was predicted to locate in cytoplasm; DoPP2C1 had high identities (56.3%-73.7%) with various PP2C proteins in plants; DoPP2C1 was closely related to Oryza sativa OsPP2C62, Sorghum bicolor XP_002462907, Hordeum vulgare BAK00362 and Triticum urartu EMS47641 proteins, and belonged to the Group F1 of the PP2C evolutionary tree; DoPP2C1 gene was differentially expressed in the three included organs. The transcripts were more abundant in the roots and stems, with 7.57 and 1.79 fold, respectively, over that in the leaves. Conclusion Molecular characterization of DoPP2C1 gene was obtained, which will be useful for further functional determination of the gene involving in the growth and development, physiological stress adaptations, and secondary metabolic regulations of D. officinale.

中国医学科学院医学与健康科技创新工程经费（2017-I2M-3-013）；陕西省普通高校青年杰出人才支持计划项目；咸阳市中青年科技创新领军人才项目