Wang Yan-Min, Zhang Yi-Ming, Zhang Xin, Zhao Xin, Zhang Yu, Wang Chao, Wang Yu-Cheng, Wang Liu-Qiang
State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Dongxiaofu 1, Xiangshan Road, Beijing 100091, China.
State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 51 Hexing Road, Harbin 150040, China.
Tree Physiol. 2021 Dec 4;41(12):2424-2437. doi: 10.1093/treephys/tpab084.
Low temperature is a major stress that severely affects plant growth and development. Inducer of CBF expression 1 (ICE1) plays a key role in plant cold tolerance by regulating the expression of cold stress-responsive genes. In the present study, we characterized the function and underlying regulatory mechanism of PsnICE1 from Xiaohei poplar (Populus simonii × Populus nigra). PsnICE1 was significantly induced in response to cold stress in the roots, stems and leaves. PsnICE1 proteins were found to localize to the nucleus and exert transactivation activity via their N-terminal transactivation domain. Compared with non-transgenic poplar, transgenic poplar overexpressing PsnICE1 showed substantially enhanced tolerance to cold stress, with higher survival rates and antioxidant enzyme activity levels and reduced reactive oxygen species (ROS) accumulation. In contrast, plants with RNA inhibition-mediated silencing of PsnICE1 showed the opposite phenotype. PsnICE1 can bind to H-box element and abscisic acid-responsive element (ABRE), and more importantly, it mainly binds to IBS1 (a newly discovered cis-acting element) and E-box elements to regulate stress-related genes involved in ROS scavenging. Overall, these results indicated that PsnICE1 functions as a positive regulator of cold tolerance and serves as a potential candidate gene for plant cold tolerance improvement via molecular breeding.
低温是严重影响植物生长发育的主要胁迫因素。CBF表达诱导因子1（ICE1）通过调控冷胁迫响应基因的表达在植物耐寒性中起关键作用。在本研究中，我们对小黑杨（Populus simonii×Populus nigra）的PsnICE1的功能及其潜在调控机制进行了表征。PsnICE1在根、茎和叶中对冷胁迫有显著诱导。发现PsnICE1蛋白定位于细胞核，并通过其N端反式激活结构域发挥反式激活活性。与非转基因杨树相比，过表达PsnICE1的转基因杨树对冷胁迫的耐受性显著增强，存活率和抗氧化酶活性水平更高，活性氧（ROS）积累减少。相反，RNA干扰介导的PsnICE1沉默植株表现出相反的表型。PsnICE1可以与H盒元件和脱落酸响应元件（ABRE）结合，更重要的是，它主要与IBS1（一个新发现的顺式作用元件）和E盒元件结合，以调控参与ROS清除的胁迫相关基因。总体而言，这些结果表明PsnICE1作为耐寒性的正调控因子，是通过分子育种提高植物耐寒性的潜在候选基因。
