Rice–arsenate interactions in hydroponics: a three-gene model for tolerance

Abstract

In this study, the genetic mapping of the tolerance of root growth to 13.3 μM arsenate [As(V)] using the Bala×Azucena population is improved, and candidate genes for further study are identified. A remarkable three-gene model of tolerance is advanced, which appears to involve epistatic interaction between three major genes, two on chromosome 6 and one on chromosome 10. Any combination of two of these genes inherited from the tolerant parent leads to the plant having tolerance. Lists of potential positional candidate genes are presented. These are then refined using whole genome transcriptomics data and bioinformatics. Physiological evidence is also provided that genes related to phosphate transport are unlikely to be behind the genetic loci conferring tolerance. These results offer testable hypotheses for genes related to As(V) tolerance that might offer strategies for mitigating arsenic (As) accumulation in consumed rice.

Arsenate-Resistant Genes in Egyptian Rice Cultivars as Soil Pollution Sensors

“…Results indicated combination between the plant disease resistance genes with outer membrane lipoprotein, which affect the physiological parameters for the cell to diminish the effect of the (As). These results are in agreement with those obtained by Norton who demonstrated three-genes in rice contaminated with (As) and the involvement of epistemic interaction between these genes [41]. They proved also physiological evidence that genes related to phosphate transport are unlikely to be behind the genetic loci conferring tolerance which confirmed the induction of the Om1A among genes discovered in the present study.…”

“…Five genes have significant differences in gene expression under As (V) treatment in the candidate gene region on chromosome 10. Induction of three different hypothetical proteins in the treated rice cultivars especially those grown on medium contains high As concentrations (1 and 10 mg/l) is supported by results obtained by Norton [41]. In that study two genes showed higher levels of gene expression in the rice cultivar (Bala) i.e.…”

“…The mechanism of how they tolerate high (As) burdens in their tissues is not well understood, although tolerance is not due to enhanced phytochelatin production or metabolism of inorganic As to organic species. The role of methylation as a detoxification mechanism in plants has not been fully investigated, although it is clear that >10% of a plant's (As) burden can be dimethyl arsenate DMA(V) depending on As exposure concentrations and on nutrition [41,44]. In the present study it is proved that at least three rice cultivars are able to accumulate high amounts of As.…”

Genetic mapping of the rice ionome in leaves and grain: identification of QTLs for 17 elements including arsenic, cadmium, iron and selenium

“…The parents of the mapping population selected for this study have previously been shown to differ in their arsenate tolerance (Dasgupta et al 2004) and a genetic model has been proposed for this (Norton et al 2008).…”

Comparative Proteomic Analysis of Rice Shoots Exposed to High Arsenate

“…However, these studies cannot provide a comprehensive understanding on the molecular mechanisms of the arsenic toxicity response in rice. Recently, two transcriptomic studies on rice under arsenic stress were performed (Norton et al ; Chakrabarty et al ). Studies of the non‐coding miRNAs were also conducted on rice exposed to arsenite and arsenate (Tuli et al ).…”