利用正电子发射的 65Zn 示踪剂对锌摄取和转运进行表征，并分析两个 Lotus japonicus 品系中与转运相关的基因表达。

Characterization of zinc uptake and translocation visualized with positron-emitting 65Zn tracer and analysis of transport-related gene expression in two Lotus japonicus accessions.

机构信息

Takasaki Advanced Radiation Research Institute, National Institutes for Quantum Science and Technology (QST), Gunma, 370-1292Japan.

Faculty of Life and Environmental Sciences, University of Tsukuba, Ibaraki, 305-8572Japan.

出版信息

Ann Bot. 2022 Dec 16;130(6):799-810. doi: 10.1093/aob/mcac101.

DOI:10.1093/aob/mcac101

PMID:35948001

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC9758300/

Abstract

BACKGROUND AND AIMS

Zinc (Zn) is an essential element for humans and plants. However, Zn deficiency is widespread and 25 % of the world's population is at risk of Zn deficiency. To overcome the deficiency of Zn intake, crops with high Zn content are required. However, most crop-producing areas have Zn-deficient soils, therefore crops with excellent Zn uptake/transport characteristics (i.e. high Zn efficiency) are needed. Our objective was to identify the crucial factors responsible for high Zn efficiency in the legume Lotus japonicus.

METHODS

We evaluated Zn efficiency by static and real-time visualization of radioactive Zn (65Zn) uptake/transport in two L. japonicus accessions, MG-20 and B-129, that differ in Zn efficiency. The combination of visualization methods verified the dynamics of Zn accumulation and transport within the plant. We compared gene expression under a normal Zn concentration (control) and Zn deficiency to evaluate genetic factors that may determine the differential Zn efficiency of the accessions.

KEY RESULTS

The accession B-129 accumulated almost twice the amount of Zn as MG-20. In the static 65Zn images, 65Zn accumulated in meristematic tissues, such as root tips and the shoot apex, in both accessions. The positron-emitting tracer imaging system (PETIS), which follows the transport process in real time, revealed that 65Zn transport to the shoot was more rapid in B-129 than in MG-20. Many genes associated with Zn uptake and transport were more highly expressed in B-129 than in MG-20 under the control condition. These gene expression patterns under Zn deficiency differed from those under the control Zn condition.

CONCLUSIONS

PETIS confirmed that the real-time transport of 65Zn to the shoot was faster in B-129 than in MG-20. The high Zn efficiency of B-129 may be due to the elevated expression of a suite of Zn uptake- and transport-related genes.

摘要

背景与目的

锌（Zn）是人和植物必需的元素。然而，Zn 缺乏广泛存在，全球有 25%的人口面临 Zn 缺乏的风险。为了克服 Zn 摄入不足的问题，需要高 Zn 含量的作物。但是，大多数作物种植区的土壤都缺乏 Zn，因此需要具有良好 Zn 吸收/转运特性（即高 Zn 效率）的作物。我们的目标是确定豆科植物百脉根中高 Zn 效率的关键因素。

方法

我们通过对两个不同 Zn 效率的百脉根品系 MG-20 和 B-129 进行放射性 Zn（65Zn）吸收/转运的静态和实时可视化，评估了 Zn 效率。可视化方法的结合验证了 Zn 在植物体内积累和转运的动态。我们比较了在正常 Zn 浓度（对照）和 Zn 缺乏条件下的基因表达，以评估可能决定品系差异 Zn 效率的遗传因素。

主要结果

品系 B-129 积累的 Zn 量几乎是 MG-20 的两倍。在静态 65Zn 图像中，65Zn 积累在分生组织组织中，如根尖和茎尖。正电子发射追踪成像系统（PETIS）实时跟踪转运过程，结果显示，B-129 中 65Zn 向地上部的转运比 MG-20 更快。在对照条件下，许多与 Zn 吸收和转运相关的基因在 B-129 中的表达水平高于 MG-20。在 Zn 缺乏条件下，这些基因的表达模式与对照 Zn 条件下的表达模式不同。