Deficiency of zinc (Zn) and iron (Fe) is common in apple grown in orchards, which affects fruit yield and quality. However, the mechanisms of absorption and transport of Zn and Fe in apples are still unclear. In the present study, we aimed to identify MdZIP genes and explore the mechanism of response of MdZIPs to Zn and Fe deficiencies. Eighteen Zn- and Fe-regulated transporter-like protein (ZIP) family members were identified in apple (Malus domestica L.) and named according to their chromosomal location. Phylogenetic analysis divided MdZIPs into four groups, and the most closely related MdZIPs in the phylogenetic tree showed similar gene structures and protein motifs. Expression pattern analysis indicated that ZIP genes in apple were differentially expressed among tissues and developmental stages under Zn and Fe deficiency. The overexpression of MdZIP10 increased the content of Zn and Fe in Arabidopsis thaliana L. and MdZIP10 played crucial roles in the uptake and transport of Zn and Fe. MdZIP10 was able to rescue growth of Zn2+ and Fe2+ uptake defective yeast mutants under Zn2+ and Fe2+ deficient conditions, respectively. Symptoms of Zn and Fe deficiency were alleviated in the MdZIP10 transgenic plants. The expression of genes related to Fe and Zn uptake and transport was induced in the MdZIP10 transgenic plants, thereby stimulating endogenous Fe and Zn uptake and transport mechanisms. The present study lays the foundation for future functional analysis of ZIP genes in apple.

中文翻译：

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苹果中锌和铁调节的转运蛋白样蛋白家族成员的全基因组分析和ZIP10的功能验证。

果园里的苹果普遍缺乏锌（Zn）和铁（Fe），这会影响果实的产量和品质。但是，苹果中锌和铁的吸收和运输机制仍不清楚。在本研究中，我们旨在鉴定MdZIP基因并探索MdZIP对锌和铁缺乏的响应机制。在苹果（Malus domestica L.）中鉴定了18个Zn和Fe调节的转运蛋白样蛋白（ZIP）家族成员，并根据它们的染色体位置命名。系统发育分析将MdZIPs分为四类，在系统发育树中关系最密切的MdZIPs具有相似的基因结构和蛋白质基序。表达模式分析表明，锌和铁缺乏时苹果中的ZIP基因在组织和发育阶段差异表达。MdZIP10的过表达增加了拟南芥中Zn和Fe的含量，MdZIP10在Zn和Fe的吸收和运输中起着至关重要的作用。MdZIP10能够挽救Zn2 +和Fe2 +缺乏条件下Zn2 +和Fe2 +摄取缺陷型酵母突变体的生长。MdZIP10转基因植物中锌和铁缺乏的症状得到缓解。在MdZIP10转基因植物中诱导了与铁和锌的吸收和运输相关的基因的表达，从而刺激了内源性铁和锌的吸收和运输机制。本研究为苹果ZIP基因的未来功能分析奠定了基础。MdZIP10能够挽救Zn2 +和Fe2 +缺陷条件下Zn2 +和Fe2 +摄取缺陷型酵母突变体的生长。MdZIP10转基因植物中锌和铁缺乏的症状得到缓解。在MdZIP10转基因植物中诱导了与铁和锌的吸收和运输相关的基因的表达，从而刺激了内源性铁和锌的吸收和运输机制。本研究为苹果ZIP基因的未来功能分析奠定了基础。MdZIP10能够挽救Zn2 +和Fe2 +缺乏条件下Zn2 +和Fe2 +摄取缺陷型酵母突变体的生长。MdZIP10转基因植物中锌和铁缺乏的症状得到缓解。在MdZIP10转基因植物中诱导了与铁和锌的吸收和运输相关的基因的表达，从而刺激了内源性铁和锌的吸收和运输机制。本研究为苹果ZIP基因的未来功能分析奠定了基础。