Functional characterization of two half‐size ABC transporter genes in aluminium‐accumulating buckwheat

Abstract

Buckwheat (Fagopyrum esculentum Moench) is able to detoxify high aluminium (Al) internally by sequestering it to the vacuoles in the leaves; however, the molecular mechanisms underlying this sequestration are unknown. We performed proteomic analysis with the leaf tonoplast-rich fraction and identified two half-size ABC transporters; FeASL1.1 and FeALS1.2. We investigated the gene expression patterns and subcellular localization. To demonstrate their physiological role, we expressed FeALS1.1 or FeALS1.2 in the Arabidopsis atals1 mutant under the control of AtALS1 promoter. FeALS1.1 expression was upregulated by Al in both the leaves and the roots, and its expression level in the roots was six times higher than its homologous gene (AtALS1) of Arabidopsis. FeALS1.2 expression, however, was not affected by Al but showed a 39 times higher expression level than AtALS1 in the leaves. When FeALS1.1 or FeALS1.2 was expressed in atals1, both of them recovered their Al tolerance through altering the subcellular localization of Al in root cells. Taken together, our results indicate that FeALS1.1 and FeALS1.2 are involved in the internal detoxification of Al in the roots and leaves, respectively, by sequestering Al into the vacuoles. Their high expression is probably required for high Al tolerance in buckwheat.

Genome-Wide Transcriptome Analysis Reveals Conserved and Distinct Molecular Mechanisms of Al Resistance in Buckwheat (Fagopyrum esculentum Moench) Leaves

“…In the buckwheat root tip, we identified a gene encoding FeALS1 and a gene encoding FeIREG1, which is consistent with a previous report [ 17 , 20 ]. Very recently, based on the proteomic analysis of a tonoplast-rich fraction, Lei et al identified two FeALS1 proteins—FeALS1.1 and FeALS1.2—from buckwheat leaves, and demonstrated their function as tonoplast-localized transporters for Al sequestration into vacuoles [ 40 ]. While the expression of FeALS1.1 was induced by Al both in the roots and shoots, FeALS1.2 was constitutively expressed.…”

Comparative Transcriptome Analysis of Two Contrasting Soybean Varieties in Response to Aluminum Toxicity

“…For example, in buckwheat ( Fagopyrum esculentum Moench), internal detoxification of Al is achieved by Al-oxalate and this complex was sequestrated in the vacuoles of the leaves [ 22 , 23 , 24 , 25 ]. Two genes from buckwheat, FeALS1.1 and FeALS1.2 , which belong to the half-size ABC transporter genes, were found to play a role in the internal detoxification of Al [ 26 ]. For external detoxification, plant root apexes exudate organic acids to chelate Al in the rhizosphere [ 27 , 28 , 29 ].…”

Efficient transient gene expression system using buckwheat hypocotyl protoplasts for large-scale experiments

“…In Arabidopsis, protein-protein and DNA-protein interactions in plant cells have been examined in a high-throughput manner Kato 2007, Wehner et al 2011). In buckwheat, methods for protoplast isolation and transient gene expression have been reported previously, but have not been optimized for a high-throughput platform (Lei et al 2017a, 2017b, Shen et al 2002.…”