Cadmium (Cd) is a highly toxic pollutant to all organisms due to its solubility in water, which determines a rapid distribution in the ecosystem. Uptake of this heavy metal by crop plants is the main entry pathway into the food chain. To identify the genetic and physiological mechanisms of plant that are able to prevent its absorption or translocation is needed to prevent Cd entering the food chain. Likewise, understanding the mechanism of Cd accumulation in the vegetative parts of hyperaccumulator plants is crucial to the promising approach of using plants as ecological remediation of Cd polluted environments. In this respect, a differential screening analysis was performed to identify genes modulated by Cadmium (Cd) treatment in Brassica juncea. Among them a gene induced after two hours of Cd exposure was selected for additional studies. Sequence analysis revealed that this gene is orthologous to an Arabidopsis thaliana MYB transcription factor. Therefore, further analyses were carried out in this species. Real Time PCR confirmed the induction by Cd of this gene in A. thaliana. Knock-out myb mutant was more tolerant to Cd in seed germination compared to wild-type, and showed different distribution of this heavy metal, in shoot and root. In addition, myb mutant presented a reduced leaf area and smaller protoplast size than wild-type. Comparative microarray analysis between wild-type and myb mutant revealed the upregulation of genes involved in Cd response and in calcium (Ca) homeostasis and signaling. Among them the transcription of the antiporter CAX1 (calcium exchanger 1) was higher in myb mutant compared to wild-type. Since CAX1 co-segregates with Cd tolerance in the metal hyperaccumulator A. halleri (Baliardini et al., Plant Physiol. 2015), further investigation on the role of this MYB transcription factor in this species will be presented.
Analysis of a MYB transcription factor induced by cadmium and modulated by calcium
E. Fasani;G. Dal Corso;A. Furini
2017-01-01
Abstract
Cadmium (Cd) is a highly toxic pollutant to all organisms due to its solubility in water, which determines a rapid distribution in the ecosystem. Uptake of this heavy metal by crop plants is the main entry pathway into the food chain. To identify the genetic and physiological mechanisms of plant that are able to prevent its absorption or translocation is needed to prevent Cd entering the food chain. Likewise, understanding the mechanism of Cd accumulation in the vegetative parts of hyperaccumulator plants is crucial to the promising approach of using plants as ecological remediation of Cd polluted environments. In this respect, a differential screening analysis was performed to identify genes modulated by Cadmium (Cd) treatment in Brassica juncea. Among them a gene induced after two hours of Cd exposure was selected for additional studies. Sequence analysis revealed that this gene is orthologous to an Arabidopsis thaliana MYB transcription factor. Therefore, further analyses were carried out in this species. Real Time PCR confirmed the induction by Cd of this gene in A. thaliana. Knock-out myb mutant was more tolerant to Cd in seed germination compared to wild-type, and showed different distribution of this heavy metal, in shoot and root. In addition, myb mutant presented a reduced leaf area and smaller protoplast size than wild-type. Comparative microarray analysis between wild-type and myb mutant revealed the upregulation of genes involved in Cd response and in calcium (Ca) homeostasis and signaling. Among them the transcription of the antiporter CAX1 (calcium exchanger 1) was higher in myb mutant compared to wild-type. Since CAX1 co-segregates with Cd tolerance in the metal hyperaccumulator A. halleri (Baliardini et al., Plant Physiol. 2015), further investigation on the role of this MYB transcription factor in this species will be presented.
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