Abstract
BackgroundArsenic (As) is a toxic metalloid found ubiquitously in the environment and widely considered an acute poison and carcinogen. However, the molecular mechanisms of the plant response to As and ensuing tolerance have not been extensively characterized. Here, we report on transcriptional changes with As treatment in two Arabidopsis accessions, Col-0 and Ws-2.ResultsThe root elongation rate was greater for Col-0 than Ws-2 with As exposure. Accumulation of As was lower in the more tolerant accession Col-0 than in Ws-2. We compared the effect of As exposure on genome-wide gene expression in the two accessions by comparative microarray assay. The genes related to heat response and oxidative stresses were common to both accessions, which indicates conserved As stress-associated responses for the two accessions. Most of the specific response genes encoded heat shock proteins, heat shock factors, ubiquitin and aquaporin transporters. Genes coding for ethylene-signalling components were enriched in As-tolerant Col-0 with As exposure. A tolerance-associated gene candidate encoding Leucine-Rich Repeat receptor-like kinase VIII (LRR-RLK VIII) was selected for functional characterization. Genetic loss-of-function analysis of the LRR-RLK VIII gene revealed altered As sensitivity and the metal accumulation in roots.ConclusionsThus, ethylene-related pathways, maintenance of protein structure and LRR-RLK VIII-mediated signalling may be important mechanisms for toxicity and tolerance to As in the species. Here, we provide a comprehensive survey of global transcriptional regulation for As and identify stress- and tolerance-associated genes responding to As.
Highlights
Arsenic (As) is a toxic metalloid found ubiquitously in the environment and widely considered an acute poison and carcinogen
Effects of As stress on root elongation in Arabidopsis accessions Col-0 and Ws-2 Root growth inhibition is the primary response of the plant exposed to heavy metals
We analyzed the effect of As (V) exposure on primary root elongation to evaluate As toxicity and tolerance in A. thaliana accessions, including Col-0, Ws-2 and Ler-0
Summary
Arsenic (As) is a toxic metalloid found ubiquitously in the environment and widely considered an acute poison and carcinogen. Arsenic (As) is a ubiquitously present non-essential metalloid of serious environmental concern because of everincreasing contamination [1,2]. Alterations of root architecture and inhibition of root elongation are considered primary symptoms of As-toxicity [9,10]. In many circumstances, it is the As-sensitivity of the root that limits the productivity of the entire plant [11]. Plants exposed to As show inhibited root growth and reduced photosynthetic rate [8,12]. Upregulated generally by As (V) Heat response Col-0, Ws-2 Oxidative stress Chitin response.
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