Characterization of zinc uptake and translocation visualized with positron-emitting 65Zn tracer and analysis of transport-related gene expression in two Lotus japonicus accessions. (10th August 2022)

• Record Type: Journal Article
• Authors: Noda, Yusaku; Furukawa, Jun; Suzui, Nobuo; Yin, Yong-Gen; Matsuoka, Keita; Kawachi, Naoki; Satoh, Shinobu
• Is Part Of: Annals of botany. Volume 130:Number 6(2022)
• Page Start: 799
• Page End: 810
• Publication Date: 2022-08-10
• Subjects: Zinc -- Lotus japonicus -- uptake -- translocation -- positron emitting tracer imaging system -- gene expression; Botany -- Periodicals; 580
• DOI: 10.1093/aob/mcac101
• Languages: English
• ISSNs: 0305-7364

Abstract

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 ( 65 Zn) 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 65 Zn images, 65 Zn 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 65 Zn 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 65 Zn 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.