Low temperature is a major stress that severely affects plant growth and development. ICE1 (Inducer of CBF Expression 1) 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 × P. 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 thier 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 and ABRE elements, 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.

中文翻译：

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杨树 PsnICE1 通过与不同的顺式作用元件结合以提高活性氧清除能力来增强耐寒性

低温是严重影响植物生长发育的主要胁迫。ICE1 ( I nducer of C BF E expression 1 )通过调节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 × P. nigra）中PsnICE1的功能和潜在调控机制进行了表征。PsnICE1对根、茎和叶的冷胁迫显着诱导。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着增强，具有更高的存活率和抗氧化酶活性水平，并减少了活性氧 (ROS) 的积累。相反，具有 RNA 抑制介导的PsnICE1沉默的植物表现出相反的表型。PsnICE1可以与H-box和ABRE元件结合，更重要的是，它主要与IBS1（一种新发现的顺式作用元件）和E-box元件结合，调节参与ROS清除的应激相关基因。总体而言，这些结果表明PsnICE1作为耐寒性的正调节因子，可作为通过分子育种提高植物耐寒性的潜在候选基因。