High salinity is one of the major environment factors threatening crop productivity and quality. Identification and function characterization of stress-related transcription factors (TFs) can provide genetic resources for transgenic plants to improve their tolerance to salt stress. In this study, a total of 49 Homeodomain-leucine zipper (HD-ZIP) genes in the tomato genome were identified and the expression profiling of all HD-Zip III members under salt and hormone treatments was investigated. A member of the HD-Zip III sub-family, Solanum lycopersicon homeodomain-leucine zipper 34 (SlHDZ34), significantly responded to salt stress. Under salinity, compared with control, silencing SlHDZ34 in tomato inhibited plant growth, including shorter plant height and less dry weight of shoot and root; promoted the accumulation of reactive oxygen species (ROS) leading to severe oxidative damage; in addition, lower photosynthetic rates and reduced abscisic acid (ABA) biosynthetic genes expressions were detected in SlHDZ34-silenced plants. Collectively, our findings revealed that SlHDZ34 plays a critical role in tomato tolerance to salinity stress. Our work can provide a promising candidate for future breeding salt-tolerant tomatoes.

高盐度是威胁作物生产力和质量的主要环境因素之一。胁迫相关转录因子（TFs）的鉴定和功能表征可以为转基因植物提高其对盐胁迫的耐受性提供遗传资源。在这项研究中，共鉴定了番茄基因组中的 49 个同源域-亮氨酸拉链 (HD-ZIP) 基因，并研究了盐和激素处理下所有 HD-Zip III 成员的表达谱。HD-Zip III 亚家族的一个成员，茄属番茄同源域-亮氨酸拉链 34 (SlHDZ34)，对盐胁迫有显着响应。在盐度下，与对照相比，沉默SlHDZ34在番茄中抑制植物生长，包括较短的株高和较少的芽和根干重；促进活性氧（ROS）的积累，导致严重的氧化损伤；此外，在SlHDZ34沉默的植物中检测到较低的光合速率和减少的脱落酸 (ABA) 生物合成基因表达。总的来说，我们的研究结果表明SlHDZ34在番茄对盐分胁迫的耐受性中起着关键作用。我们的工作可以为未来培育耐盐番茄提供一个有希望的候选者。