Functional characterization of a silicon transporter gene implicated in silicon distribution in barley

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

Silicon (Si) is a beneficial element for plant growth. In barley (Hordeum vulgare), Si uptake by the roots is mainly mediated by a Si channel, Low Silicon1 (HvLsi1), and an efflux transporter, HvLsi2. However, transporters involved in the distribution of Si in the shoots have not been identified. Here, we report the functional characterization of a homolog of HvLsi1, HvLsi6. HvLsi6 showed permeability for Si and localized to the plasma membrane. At the vegetative growth stage, HvLsi6 was expressed in both the roots and shoots. The expression level was unaffected by Si supply. In the roots, HvLsi6 was localized in epidermis and cortex cells of the tips, while in the leaf blades and sheaths, HvLsi6 was only localized at parenchyma cells of vascular bundles. At the reproductive growth stage, high expression of HvLsi6 was also found in the nodes. HvLsi6 in node I was polarly located at the transfer cells surrounding the enlarged vascular bundles toward the numerous xylem vessels. These results suggest that HvLsi6 is involved in Si uptake in the root tips, xylem unloading of Si in leaf blade and sheath, and intervascular transfer of Si in the nodes. Furthermore, HvLsi2 was found to be localized at the parenchyma cell layer adjacent to the transfer cells with opposite polarity of HvLsi6, suggesting that the coupling of HvLsi6 and HvLsi2 is involved in the intervascular transfer of Si at the nodes. Si translocated via the enlarged vascular bundles is unloaded to the transfer cells by HvLsi6, followed by HvLsi2 to reload Si to the diffuse vascular bundles, which are connected to the upper part of the plant, especially the panicles, the ultimate Si sink.

Original languageEnglish
Pages (from-to)1491-1497
Number of pages7
JournalPlant Physiology
Volume160
Issue number3
DOIs
Publication statusPublished - Nov 2012

Fingerprint

Silicon
Hordeum
silicon
transporters
barley
Genes
genes
vascular bundles
Blood Vessels
Xylem
cells
leaf blade
parenchyma (plant tissue)
Growth
developmental stages
uptake mechanisms
shoots
Meristem
xylem vessels
epidermis (plant)

ASJC Scopus subject areas

  • Plant Science
  • Genetics
  • Physiology

Cite this

Functional characterization of a silicon transporter gene implicated in silicon distribution in barley. / Yamaji, Naoki; Chiba, Yukako; Mitani, Namiki; Ma, Jian Feng.

In: Plant Physiology, Vol. 160, No. 3, 11.2012, p. 1491-1497.

Research output: Contribution to journalArticle

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