Comparative biochemical and transcriptional profiling of two contrasting varieties of Brassica juncea L. in response to arsenic exposure reveals mechanisms of stress perception and tolerance
Open Access
- 15 June 2009
- journal article
- research article
- Published by Oxford University Press (OUP) in Journal of Experimental Botany
- Vol. 60 (12), 3419-3431
- https://doi.org/10.1093/jxb/erp181
Abstract
The mechanisms of perception of arsenic (As)-induced stress and ensuing tolerance in plants remain unresolved. To obtain an insight into these mechanisms, biochemical and transcriptional profiling of two contrasting genotypes of Brassica juncea was performed. After screening 14 varieties for As tolerance, one tolerant (TPM-1) and one sensitive (TM-4) variety were selected and exposed to arsenate [As(V)] and arsenite [As(III)] for 7 d and 15 d for biochemical analyses. The tolerant variety (TPM-1) demonstrated higher accumulation of As upon exposure to both 500 μM As(V) and 250 μM As(III) [49 μg g−1 and 37 μg g−1 dry weight (dw) after 15 d] as well as a better response of thiol metabolism as compared with the responses observed in the sensitive variety (TM-4). Transcriptional profiling of selected genes that are known to be responsive to sulphur depletion and/or metal(loid) stress was conducted in 15-d-old seedlings after 3 h and 6 h exposure to 250 μM As(III). The results showed an up-regulation of sulphate transporters and auxin and jasmonate biosynthesis pathway genes, whereas there was a down-regulation of ethylene biosynthesis and cytokinin-responsive genes in TPM-1 within 6 h of exposure to As(III). This suggested that perception of As-induced stress was presumably mediated through an integrated modulation in hormonal functioning that led to both short- and long-term adaptations to combat the stress. Such a coordinated response of hormones was not seen in the sensitive variety. In conclusion, an early perception of As-induced stress followed by coordinated responses of various pathways was responsible for As tolerance in TPM-1.Keywords
This publication has 53 references indexed in Scilit:
- Thiourea modulates the expression and activity profile of mtATPase under salinity stress in seeds of Brassica junceaAnnals of Botany, 2008
- Transcriptional responses of Arabidopsis thaliana plants to As (V) stressBMC Plant Biology, 2008
- Rice–arsenate interactions in hydroponics: whole genome transcriptional analysisJournal of Experimental Botany, 2008
- Ethylene Regulates Root Growth through Effects on Auxin Biosynthesis and Transport-Dependent Auxin DistributionPlant Cell, 2007
- A Mutant of the Arabidopsis Phosphate Transporter PHT1;1 Displays Enhanced Arsenic AccumulationPlant Cell, 2007
- Specificity and Similarity of Functions of the Aux/IAA Genes in Auxin Signaling of Arabidopsis Revealed by Promoter-Exchange Experiments among MSG2/IAA19, AXR2/IAA7, and SLR/IAA14Plant Physiology, 2007
- TheMedicago truncatulaCRE1 Cytokinin Receptor Regulates Lateral Root Development and Early Symbiotic Interaction withSinorhizobium melilotiPlant Cell, 2006
- Standardized determination of real-time PCR efficiency from a single reaction set-upNucleic Acids Research, 2003
- Trp-dependent auxin biosynthesis in Arabidopsis: involvement of cytochrome P450s CYP79B2 and CYP79B3Genes & Development, 2002
- Relative expression software tool (REST(C)) for group-wise comparison and statistical analysis of relative expression results in real-time PCRNucleic Acids Research, 2002