Skip to main content
eScholarship
Open Access Publications from the University of California

Department of Plant Sciences

UC Davis

Barley metal ion transport proteins involved in manganese acquisition and homeostasis

Abstract

Manganese (Mn) toxicity is a major problem for plant growth, often caused by acidic soils leading to an excessive plant availability of Mn2+. However, Mn deficiency is also a major nutritional disorder, commonly observed on slightly alkaline soils, which are favoring oxidation of soluble Mn2+ to the plant unavailable form MnO2. The work reported here was initiated with the aim of identifying and characterizing barley Mn2+ transport proteins. Using yeast as a model system we have identified and characterized barley genes encoding Mn2+ transport proteins. The plasma membrane localized HvIRT1 protein is a broad range metal ion transporter. The HvIRT1 transcript expression was induced under Mn and Fe deficiency and the expression level was correlated with the Mn2+ uptake capacity, suggesting an important role of HvIRT1 in Mn2+ acquisition. Two additional genes encoding Mn2+ transport proteins were identified in a Mn2+ tolerance yeast assay; one belonging to the CDF family designated HvMTP8.1 and one homologous gene to the yeast CCC1, named HvVIT1. It is proposed that HvMTP8.1 has a role in Mn2+ efflux mechanisms into the apoplast whereas HvVIT1 are involved in Mn2+ sequestration into internal cellular compartments. The results presented provide the basis for an improved understanding of the mechanisms involved in Mn2+ acquisition and homeostasis in crop plants. This information will facilitate engineering of genotypes able to grow efficiently on marginal soils.

Main Content
For improved accessibility of PDF content, download the file to your device.
Current View