Arsenic Transport, Metabolism and Toxicity in Plants

Sudhakar Srivastava, Rudra D. Tripathi, Om Parkash Dhankhera, Munish Kumar Upadhyay

Abstract


Arsenic is a toxic metalloid present in large areas in some parts of world including densely
populated areas of Bangladesh and West Bengal, India. Being a carcinogenic metalloid, it
affects the health of millions of people of affected areas through drinking water and food.
Nonetheless, the spread of arsenic contamination reaches to non-affected areas also. Rice
is the major crop of the affected areas and is thus the most important carrier of arsenic in
grains and in various rice based products throughout the world. Arsenic exists in various
inorganic and organic forms with arsenite and arsenate being the major inorganic forms of
concern. This global issue has got attraction of a number of studies to understand the
details of arsenic uptake, transport, metabolism and toxicity in plants. The transporters
responsible for the uptake and root-to-shoot transport of inorganic arsenic have been
identified. In addition, transporters responsible for sequestration of arsenic in vacuoles
are also discovered. Inside the plants, arsenic induces the production of reactive oxygen
species and causes oxidative stress leading to damage to proteins, carbohydrates, lipids
and DNA and ultimately cell death. Various antioxidant enzymes and molecules are
increased to counteract the oxidative stress. In addition, specific arsenic-binding ligands
like phytochelatins are synthesized to chelate and sequester arsenic in vacuoles. This is
achieved througth concerted modulation of synthesis and degration of thiols. A number of
molecular changes including altered expression of microRNAs and transcription factors
take place. The available knowledge about the arsenic metabolism and its toxicity paves
the way to tackle the issue. This update discusses not only the present knowledge on this
issue but also the lacunae, which need to be filled.

Keywords


Anthropogenic, impacts Arsenic, contamination, Arsenic transport, Carcinogen Metabolism, Toxicity

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DOI: http://dx.doi.org/10.18811/ijpen.v2i1-2.6614

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