Root transcripts associated with arsenic accumulation in hyperaccumulator Pteris vittata.

Hyperaccumulation of arsenic (As) by brake fern Pteris vittata has been described as an important genetic trait that provides an option for development of a sustainable phytoremediation process for As mitigation. Accumulation of very high concentration of arsenic in above-ground tissues may be the result of arsenic vacuole compartmentalization, but the mechanism(s) of arsenic uptake and transport by underground tissues are largely unknown. In this study, we made an attempt towards understanding the molecular mechanism of As hyperaccumulation in this plant. A time-dependent As accumulation study indicates an exponential accumulation of As from 7 to 30 days of arsenic exposure in fronds, and day 3-7 in roots. Root transcriptome analysis identified 554,973 transcripts. Further, subsets of 824 transcripts were differentially expressed between treated and control samples. Many of the genes of critical As-stress response, transcription factors and metal transporters, biosynthesis of chelating compounds involved in uptake and accumulation mechanisms were identified. The genes that were highly expressed such as cysteine-rich RLK, and ABC transporter G family member 26 needs further studies along with arsenite transmembrane transporter. The analysis of generated transcriptome dataset has provided valuable information and platform for further functional studies.