Arsenic Hyperaccumulator Fern Pteris vittata: Utilities for Arsenic Phytoremediation and Plant Biotechnology
Arsenic is a toxic metalloid that is widespread in the environment due to both man-made and natural causes. Soils, food, and ground water contaminated with arsenic pose serious health risks to millions of people in different parts of the World. While engineering methods to remediate arsenic-contaminated environments are available, they are often prohibitively expensive and cumbersome. It was discovered about a decade ago that the Chinese brake fern (Pteris vittata) had an extraordinary ability to tolerate and hyperaccumulate arsenic, up to about 2% of dry weight in its fronds. This opened up new opportunities to develop the brake fern for a cost-effective green technology to remediate arsenic-contaminated environments. The objective of this review is to highlight some of the salient findings on this and related ferns regarding their arsenic tolerance and hyperaccumulation traits. Investigations have shown that arsenic hyperaccumulation in brake fern has evolved as a defense against herbivory. Research employing molecular biology tools have identified some of the key genes and proteins important for arsenic metabolism in this species including genes for arsenic-induced oxidative stress. Comparative biochemistry of how organisms adapt to arsenic suggests that many other fern genes related to arsenic transport and metabolism are yet to be characterized in this fern. Our research indicates that brake fern could be a source of genes that could inform us about how plants adapt to abiotic stress factors such as high temperature stress and drought that have oxidative stress as a component. Some of these genes can be expected to be valuable for improving crops for increased tolerance to stress.