HD-Zip transcription factors play an important role in regulating plants’ response to salt stress, but there have been few studies of HD-Zip transcription factors in poplar and their role in salt-stress responses. In this study, the PnHB7 was cloned from Populus nigra L., a bioinformatics analysis was conducted, and a genetic transformation vector was constructed. The results show that PnHB7 was a transcription factor belonging to the HD-Zip family I subfamily, located on chromosome 14, with a length of 717 bp, encoding 238 amino acids, a molecular formula of C₁₁₈₅H₁₈₆₁N₃₂₉O₃₈₇S₈. Multiple cis-acting elements related to stress response are contained in the upstream promoter region. Subcellular localization showed that the PnHB7:GFP fusion protein was located in the nucleus. Under a 0.4 % NaCl treatment, the growth and physiological indexes of overexpressed tobacco (Nicotiana tabacum L.) were better than those of wild-type tobacco, and salt tolerance was higher. The stress responses of tobacco seedlings transformed by 35S:pro-PnHB7:GUS showed that PnHB7 responded to abscisic acid, ethylene, methyl jasmonate, and NaCl stress. The transcriptome sequencing results of overexpressed tobacco showed that hormone-related protein genes (abscisic acid, gibberellin, ethylene, salicylic acid), oxidase genes (oxygenase, peroxidase, polyphenol oxidase) and transcription factor protein genes were significantly upregulated, and most were located in the signal pathway of ABA transduction. It is speculated that PnHB7 plays an important role in the ABA regulation pathway.

HD-Zip转录因子在调节植物对盐胁迫的响应中起着重要作用，但是很少有关于杨树中HD-Zip转录因子及其在盐胁迫响应中的作用的研究。本研究从黑杨中克隆了PnHB7，进行了生物信息学分析，并构建了遗传转化载体。结果表明，PnHB7是属于HD-Zip I家族的转录因子，位于14号染色体上，全长717 bp，编码238个氨基酸，分子式为C ₁₁₈₅ H ₁₈₆₁ N ₃₂₉ O ₃₈₇ S ₈。与应激反应有关的多个顺式作用元件包含在上游启动子区域中。亚细胞定位表明PnHB7：GFP融合蛋白位于细胞核中。在0.4％NaCl处理下，过表达烟草（Nicotiana tabacum L.）的生长和生理指标要优于野生型烟草，并且耐盐性更高。35S：pro-PnHB7：GUS转化烟草幼苗的胁迫反应表明PnHB7对脱落酸，乙烯，茉莉酸甲酯和NaCl胁迫有反应。过表达烟草的转录组测序结果表明，与激素相关的蛋白基因（脱落酸，赤霉素，乙烯，水杨酸），氧化酶基因（加氧酶，过氧化物酶，多酚氧化酶）和转录因子蛋白基因被显着上调，并且大多数位于ABA转导的信号途径。推测PnHB7在ABA调节途径中起重要作用。