蔡元保 杨祥燕 庞新华 李季东 林玉虹

摘  要：以澳洲坚果品种‘O.C.’为试材，利用RT-PCR技术克隆获得2个丝氨酸/苏氨酸磷酸酶基因，分别命名为MiSTPP3和MiSTPP7，其编码序列长度分别为2095 bp和1700 bp。序列分析和系统进化分析表明，MiSTPP3含有MPP_PP5_C结构域，属于PP5亚家族;MiSTPP7含有MPP_PP7结构域，属于PP7亚家族。蛋白理化性质和亚细胞定位分析表明，MiSTPP3是一个稳定的亲水性蛋白，可能定位于质膜;MiSTPP7是一个不稳定的亲水性蛋白，可能定位于线粒体基质。生物信息学分析表明，MiSTPP3和MiSTPP7都是非分泌跨膜蛋白，其二级和三级结构的主要元件都是α螺旋、无规则卷曲和延伸链。RT-qPCR分析表明，MiSTPP3和MiSTPP7在澳洲坚果根、茎、叶、花和小果中都有不同的表达量;MiSTPP3受低温胁迫下调表达，而MiSTPP7上调表达，且二者都受干旱胁迫上调表达。因此，推测MiSTPP3和MiSTPP7可能参与澳洲坚果的生长发育及逆境胁迫反应。

关键词：澳洲坚果;PP5;PP7;基因克隆;表达分析

中图分类号：S664.9      文献标识码：A

Abstract： Two serine / threonine phosphatase genes were named MiSTPP3 and MiSTPP7， with coding sequences 2095 bp and 1700 bp in length， respectively， which were cloned by RT-PCR from macadamia cultivar ‘O.C.’ （Macadamia integrifolia）. Sequence analysis and evolution analysis indicated that MiSTPP3 with the MPP_PP5_C domain belonged to PP5 subfamily， and MiSTPP7 with the MPP_PP7 domain belonged to PP7 subfamily. Physicochemical properties of protein and subcellular localization analysis showed that MiSTPP3 as a stable hydrophilic protein may be located in the plasma membrane， and MiSTPP7 as an unstable hydrophilic protein may be located in the mitochondrial matrix. Bioinformatics analysis indicated that MiSTPP3 and MiSTPP7 were non-secreted transmembrane proteins， α-helix， random coil and extended strand were the backbone of the secondary and 3D protein structures. RT-qPCR analysis indicated that MiSTPP3 and MiSTPP7 expressed differently in roots， stems， leaves， flowers and small fruits of M. integrifolia; MiSTPP3 was down regulated by low temperature stress， while MiSTPP7 was up-regulated， and both of them were up-regulated by drought stress. The results suggested that MiSTPP3 and MiSTPP7 may be involved in the growth and development of M. integrifolia and the stress response.

Keywords： Macadamia ternifolia; PP5; PP7; gene cloning; expression analysis

DOI： 10.3969/j.issn.1000-2561.2021.11.007

蛋白質可逆磷酸化是通过蛋白激酶和蛋白磷酸酶催化蛋白质磷酸化和去磷酸化[1-2]，这一过程几乎涉及细胞所有的生命活动，如生长发育、代谢调控、信号感知与转导、分化与衰老等[3-6]。蛋白磷酸酶催化的去磷酸化负调控蛋白激酶的生化作用，从而抑制蛋白激酶的细胞学功能，并在细胞应答信号通路中起到重要的作用，特别对于调控植物生长发育和响应逆境胁迫具有重要意义。

蛋白磷酸酶是一个庞大的蛋白家族，主要分为丝氨酸/苏氨酸蛋白磷酸酶（PSP）和酪氨酸蛋白磷酸酶（PTP）两大类，根据蛋……