Apple, as one of the most important economic forest tree species, is widely grown in the world. Abiotic stresses, such as high salinity and iron deficiency, affect apple growth and development. WRKY transcription factors (TFs) are widely involved in the responses of plants to adverse stresses. In the present study, a new WRKY gene was isolated from Malus xiaojinensis and designated as MxWRKY55. Subcellular localization showed that MxWRKY55 was localized to the nucleus. The expression level of MxWRKY55 was highly affected by salt, low-Fe, and high-Fe stresses in M. xiaojinensis seedlings. When MxWRKY55 was introduced into Arabidopsis thaliana, it greatly enhanced the salt and Fe tolerance. When dealt with high- and low-Fe stresses, the overexpression of MxWRKY55 in transgenic A. thaliana resulted in higher levels of root length and fresh weight as well as contents of chlorophyll and Fe than wild type (WT). Increased expression of MxWRKY55 in transformed A. thaliana also contributed to higher contents of chlorophyll and proline and higher activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), while malondialdehyde (MDA) content was lower, especially in response to salt stress. Therefore, these results show that MxWRKY55 plays a positive role in the process of plant resistance to salt, low-Fe, and high-Fe stresses.

苹果作为最重要的经济林木树种之一，在世界范围内得到广泛种植。非生物胁迫，例如高盐度和铁缺乏，会影响苹果的生长发育。WRKY转录因子（TFs）广泛参与植物对逆境胁迫的反应。在本研究中，从小金海棠分离出一个新的WRKY基因，命名为MxWRKY55。亚细胞定位表明MxWRKY55定位到细胞核。的表达水平MxWRKY55是高度受的盐，低Fe和高铁在强调中号。小金树幼苗。当MxWRKY55引入拟南芥，大大提高了盐和铁的耐受性。当处理高铁和低铁胁迫时，转基因拟南芥中MxWRKY55的过表达导致根系长度和鲜重以及叶绿素和铁的含量高于野生型（WT）。MxWRKY55在转化拟南芥中表达的增加还有助于提高叶绿素和脯氨酸的含量，并提高超氧化物歧化酶（SOD），过氧化物酶（POD）和过氧化氢酶（CAT）的活性，而丙二醛（MDA）含量较低，特别是在对盐胁迫的反应。因此，这些结果表明，MxWRKY55在植物抗盐，低铁和高铁胁迫的过程中发挥积极作用。