Zhai Rui, Zhang Xiangrui, Wang Shuying, Chen Shuai, Zhang Zhiqi, Zhang Yuhan, Shi Dunwen, Li Xinshu, Li Futian, Chen Guoqiang, Xu Juntian
Jiangsu Provincial Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, 222005, China.
Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, 222005, China.
Sci Rep. 2025 Mar 26;15(1):10492. doi: 10.1038/s41598-024-82161-9.
Iron is an essential microelement for all living organisms. The vacuolar iron transporters (VIT) gene family is found in various species, including yeast, fungi, protozoa, and plants, where it plays a crucial role in sequestration, homeostasis, and tolerance of the heavy metals, particularly iron and manganese. However, the presence and function of VIT genes in marine phytoplankton have not been previously reported. The study aims to identify the VIT family within the marine diatom Phaeodactylum tricornutum and to analyze the function of these genes. We conducted a comprehensive analysis of the VIT genes in P. tricornutum genome, examining their phylogenetic relationship, physicochemical properties, gene structures, conserved motifs, domains, expression profile, and cis-acting elements using in silico methods. Function analysis were performed through complementation experiments and the expression of eGFP fusion protein in yeast. Four members of the VIT family were identified in P. tricornutum. All belonging to the VTL (VIT like) group in phylogenetic tree and containing a VIT1 domain. These genes are distributed across chromosomes 2, 4, and 13, with tandem duplication of the PtVTL1 and PtVTL2 contributed to the expansion of this gene family. Expression profile showed that the PtVTL3 is induced to express highly under light condition, others are induced to express highly under dark. PtVTL2 is highly induced to express at low Fe condition, and PtVTL3 is highly induced to express at high Fe condition. Analysis of cis-acting regulatory elements indicated that these genes are primarily involved in responses to environmental stress and phytohormones. Heterologous expression of PtVTL3 successfully rescued the iron-sensitive phenotype in yeast mutant △ccc1. The expression of eGFP-PtVTL3 fusion protein in yeast demonstrated that PtVTL3 is located to the tonoplast. These findings suggest that PtVTL3 function to transport Fe across the tonoplast into the vacuole, thereby maintaining iron homeostasis in yeast. Four PtVTL genes were identified in the genome of P. tricornutum, with PtVTL3 playing a key role in iron transport at the tonoplast, highlighting its potential significance in iron homeostasis in marine diatoms.
铁是所有生物必需的微量元素。液泡铁转运蛋白（VIT）基因家族存在于包括酵母、真菌、原生动物和植物在内的各种物种中，在重金属（特别是铁和锰）的螯合、稳态和耐受性方面发挥着关键作用。然而，此前尚未报道VIT基因在海洋浮游植物中的存在和功能。本研究旨在鉴定海洋硅藻三角褐指藻中的VIT家族，并分析这些基因的功能。我们对三角褐指藻基因组中的VIT基因进行了全面分析，采用计算机模拟方法研究了它们的系统发育关系、理化性质、基因结构、保守基序、结构域、表达谱和顺式作用元件。通过互补实验和eGFP融合蛋白在酵母中的表达进行功能分析。在三角褐指藻中鉴定出了VIT家族的四个成员。它们在系统发育树中均属于VTL（类VIT）组，并含有一个VIT1结构域。这些基因分布在2号、4号和13号染色体上，PtVTL1和PtVTL2的串联重复导致了该基因家族的扩张。表达谱显示，PtVTL3在光照条件下被诱导高表达，其他基因在黑暗条件下被诱导高表达。PtVTL2在低铁条件下被高度诱导表达，PtVTL3在高铁条件下被高度诱导表达。顺式作用调控元件分析表明，这些基因主要参与对环境胁迫和植物激素的响应。PtVTL3的异源表达成功挽救了酵母突变体△ccc1中的铁敏感表型。eGFP-PtVTL3融合蛋白在酵母中的表达表明PtVTL3定位于液泡膜。这些发现表明，PtVTL3的功能是将铁转运穿过液泡膜进入液泡，从而维持酵母中的铁稳态。在三角褐指藻基因组中鉴定出了四个PtVTL基因，其中PtVTL3在液泡膜铁转运中起关键作用，突出了其在海洋硅藻铁稳态中的潜在重要性。
