Overexpression of Populus tomentosa cytosolic ascorbate peroxidase enhances abiotic stress tolerance in tobacco plants
Overexpression of Populus tomentosa cytosolic ascorbate peroxidase enhances abiotic stress tolerance in tobacco plants
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DOI：
10.1134/s1021443717020029
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发表时间：
2017-03-01
影响因子：
1.4
通讯作者：
Lu, H.
中科院分区：
文献类型：
--
作者：
Cao, S.;Du, X. -H.;Lu, H.
活性氧（ROS）在植物中起着重要作用，并受到多种ROS清除酶的调节。抗坏血酸过氧化物酶（APX）是催化过氧化氢还原为水的酶，是活性氧形成的重要组成部分，在高等植物中起着重要作用。本研究从毛白杨中克隆了一个胞质APX基因，命名为PcAPX。重组PcAPX分子量为33.24 kD，对抗坏血酸（ASA）和过氧化氢（H2O2）具有较高的活性。Real-time PCR分析表明，APX mRNA在毛白杨叶片中的表达量高于根和茎。与野生型相比，在正常条件下，转PcAPX基因烟草植株的形态无明显差异。然而，转基因植物对干旱、盐和氧化胁迫条件的抗性更强，表现为丙二醛水平降低和叶绿素水平增加。此外，降低H2O2水平，增加ASA消耗，NADP NADPH比率增加，以及转基因植物中较高的APX活性表明消除ROS的能力增加。这些数据表明，PcAPX在转基因烟草植物中的过表达可以增强对干旱，盐和氧化胁迫的耐受性。因此，APX在植物的非生物胁迫耐受性中起着至关重要的作用。
Reactive oxygen species (ROS) play key roles in plants and are regulated by several ROS-scavenging enzymes. Ascorbate peroxidase (APX), which catalyzes the reduction of hydrogen peroxide to water, a vital part of ROS formation, plays a significant role in higher plants. In this study, a cytosolic APX gene from Populus tomentosa, named PcAPX, was identified and characterized. Recombinant PcAPX had a calculated mass of 33.24 kD and showed high activity towards ascorbic acid (ASA) and hydrogen peroxide (H2O2). Real-time PCR analysis showed that APX mRNA expression levels were higher in leaves than roots or stems of P. tomentosa. Compared with wild-type, transgenic tobacco plants overexpressing PcAPX showed no significant difference in morphology under normal conditions. However, the transgenic plants were more resistant to drought, salt and oxidative stress conditions, as shown by decreased levels of malondialdehyde and increased levels of chlorophyll. Moreover, decreased H2O2 levels, increased ASA consumption, an increase in the NADP to NADPH ratio, and higher APX activity in the transgenic plants suggested an increased ability to eliminate ROS. These data suggest that PcAPX overexpression in transgenic tobacco plants can enhance tolerance to drought, salt and oxidative stress. Therefore, APX has a crucial role in abiotic stress tolerance in plants.