Abstract

Iron (Fe) is an essential micronutrient and plays an irreplaceable role in plant growth and development. Although its uptake and translocation are important biological processes, little is known about the molecular mechanism of Fe translocation within seed. Here, we characterized a novel small kernel mutant yellow stripe like 2 (ysl2) in maize (Zea mays). ZmYSL2 was predominantly expressed in developing endosperm and was found to encode a plasma membrane-localized metal–nicotianamine (NA) transporter ZmYSL2. Analysis of transporter activity revealed ZmYSL2-mediated Fe transport from endosperm to embryo during kernel development. Dysfunction of ZmYSL2 resulted in the imbalance of Fe homeostasis and abnormality of protein accumulation and starch deposition in the kernel. Significant changes of nitric oxide accumulation, mitochondrial Fe–S cluster content, and mitochondrial morphology indicated that the proper function of mitochondria was also affected in ysl2. Collectively, our study demonstrated that ZmYSL2 had a pivotal role in mediating Fe distribution within the kernel and kernel development in maize.

中文翻译：

---

玉米ZmYSL2是内核铁分配和开发所必需的。

摘要

铁（Fe）是必需的微量营养素，在植物生长发育中起着不可替代的作用。尽管其吸收和转运是重要的生物学过程，但对种子内铁转运的分子机制知之甚少。在这里，我们表征了玉米（玉米（Zea mays））中像2（ysl2）这样的新型小核突变黄色条纹。ZmYSL2主要在发育中的胚乳中表达，并被发现编码质膜定位的金属烟碱胺（NA）转运蛋白ZmYSL2。转运蛋白活性的分析显示，ZmYSL2介导的铁在胚乳发育过程中从胚乳转运到胚胎。ZmYSL2的功能障碍导致铁稳态失衡，蛋白质积累和淀粉在籽粒中沉积异常。一氧化氮累积，线粒体Fe-S簇含量和线粒体形态的显着变化表明ysl2也影响线粒体的正常功能。总体而言，我们的研究表明ZmYSL2在介导铁在玉米粒内的分布和玉米粒的发育中具有关键作用。