Li Qilong, Zhang Xiaochen, Lv Qiang, Zhu Dong, Qiu Tianhang, Xu Yu, Bao Fang, He Yikun, Hu Yong
College of Life Sciences, Capital Normal UniversityBeijing, China.
Front Plant Sci. 2017 Jul 26;8:1316. doi: 10.3389/fpls.2017.01316. eCollection 2017.
Dehydrins (DHNs) as a member of late-embryogenesis-abundant (LEA) proteins are involved in plant abiotic stress tolerance. Two dehydrins PpDHNA and PpDHNC were previously characterized from the moss Physcomitrella patens, which has been suggested to be an ideal model plant to study stress tolerance due to its adaptability to extreme environment. In this study, functions of these two genes were analyzed by heterologous expressions in Arabidopsis. Phenotype analysis revealed that overexpressing PpDHN dehydrin lines had stronger stress resistance than wild type and empty-vector control lines. These stress tolerance mainly due to the up-regulation of stress-related genes expression and mitigation to oxidative damage. The transgenic plants showed strong scavenging ability of reactive oxygen species(ROS), which was attributed to the enhancing of the content of antioxidant enzymes like superoxide dismutase (SOD) and catalase (CAT). Further analysis showed that the contents of chlorophyll and proline tended to be the appropriate level (close to non-stress environment) and the malondialdehyde (MDA) were repressed in these transgenic plants after exposure to stress. All these results suggest the PpDHNA and PpDHNC played a crucial role in response to drought and salt stress.
脱水素（DHNs）作为晚期胚胎丰富（LEA）蛋白家族的成员，参与植物对非生物胁迫的耐受性。先前已从苔藓小立碗藓中鉴定出两种脱水素PpDHNA和PpDHNC，由于其对极端环境的适应性，小立碗藓被认为是研究胁迫耐受性的理想模式植物。在本研究中，通过在拟南芥中的异源表达分析了这两个基因的功能。表型分析表明，过表达PpDHN脱水素的株系比野生型和空载体对照株系具有更强的抗逆性。这些胁迫耐受性主要归因于胁迫相关基因表达的上调以及对氧化损伤的减轻。转基因植物表现出较强的活性氧（ROS）清除能力，这归因于超氧化物歧化酶（SOD）和过氧化氢酶（CAT）等抗氧化酶含量的增加。进一步分析表明，在受到胁迫后，这些转基因植物中的叶绿素和脯氨酸含量趋于适宜水平（接近非胁迫环境），丙二醛（MDA）含量受到抑制。所有这些结果表明PpDHNA和PpDHNC在应对干旱和盐胁迫中起关键作用。
