Expression profiling of Crambe abyssinicaunder arsenate stress identifies genes and gene networks involved in arsenic metabolism and detoxification

Abstract

BackgroundArsenic contamination is widespread throughout the world and this toxic metalloid is known to cause cancers of organs such as liver, kidney, skin, and lung in human. In spite of a recent surge in arsenic related studies, we are still far from a comprehensive understanding of arsenic uptake, detoxification, and sequestration in plants. Crambe abyssinica, commonly known as 'abyssinian mustard', is a non-food, high biomass oil seed crop that is naturally tolerant to heavy metals. Moreover, it accumulates significantly higher levels of arsenic as compared to other species of the Brassicaceae family. Thus, C. abyssinica has great potential to be utilized as an ideal inedible crop for phytoremediation of heavy metals and metalloids. However, the mechanism of arsenic metabolism in higher plants, including C. abyssinica, remains elusive.ResultsTo identify the differentially expressed transcripts and the pathways involved in arsenic metabolism and detoxification, C. abyssinica plants were subjected to arsenate stress and a PCR-Select Suppression Subtraction Hybridization (SSH) approach was employed. A total of 105 differentially expressed subtracted cDNAs were sequenced which were found to represent 38 genes. Those genes encode proteins functioning as antioxidants, metal transporters, reductases, enzymes involved in the protein degradation pathway, and several novel uncharacterized proteins. The transcripts corresponding to the subtracted cDNAs showed strong upregulation by arsenate stress as confirmed by the semi-quantitative RT-PCR.ConclusionsOur study revealed novel insights into the plant defense mechanisms and the regulation of genes and gene networks in response to arsenate toxicity. The differential expression of transcripts encoding glutathione-S-transferases, antioxidants, sulfur metabolism, heat-shock proteins, metal transporters, and enzymes in the ubiquitination pathway of protein degradation as well as several unknown novel proteins serve as molecular evidence for the physiological responses to arsenate stress in plants. Additionally, many of these cDNA clones showing strong upregulation due to arsenate stress could be used as valuable markers. Further characterization of these differentially expressed genes would be useful to develop novel strategies for efficient phytoremediation as well as for engineering arsenic tolerant crops with reduced arsenic translocation to the edible parts of plants.

The bio-based economy can serve as the springboard for camelina and crambe to quit the limbo

“…Crambe is adaptable to a broad range of soils including saline and contaminated (heavy metals) ones (Artus, 2006;Paulose et al, 2010). It is also a drought tolerant crop able to grow successfully in marginal or semiarid land .…”

Identification of Genes Related to Arsenic Detoxification in Rice Roots Using Microarray Analysis

“…As concentration in rice and some vegetables are exceed the safety limits [3]. Previous studies have reported the molecular mechanism in plants during As stress [4], [5]. However, these studies carried out in the plants exposed to high As concentrations, little is known on rice roots subjected to low concentration of AsV.…”

Genetic stability of micropropagated plants of Crambe abyssinica Hochst using ISSR markers

“…The use of molecular markers in crambe reported in the literature is limited to the study of genetic diversity (Lara-Fioreze et al, 2013), identification and characterization of genetic transformants (Wang et al, 2004;Wang et al, 2006;Li et al, 2010;Xu et al, 2010;Chhikara et al, 2012;Li et al, 2013), and identification of genes of interest (Paulose et al, 2010;Cheng et al, 2013). Therefore, the results presented herein are important, because no previous studies have evaluated genetic stability using DNA molecular markers in crambe plants regenerated in vitro.…”

“…Additionally, the agronomic characteristics of crambe, such as its short life cycle of approximately 90 days, high biomass, mean seed yield of 1800-2400 kg/ha, adaptation to different climatic conditions, resistance to insects, and tolerance to abiotic stresses such as salinity, low temperature, heat, drought, and exposure to heavy metals, make it an important species within the agricultural industry (Paulose et al, 2010;Chhikara et al, 2012).…”