Problem of Mercury Toxicity in Crop Plants: Can Plant Growth Promoting Microbes (PGPM) Be an Effective Solution?
Mercury is ranked as the most toxic heavy metals. It enters into the environment due to some natural processes and anthropogenic activities. It has a property of bioaccumulation into the food chain through uptake by crop plants from the contaminated agricultural lands, leading to detrimental impact on human health. Mercury has the toxic effect on plants as it disturbs many biological processes, including photosynthesis, respiration, transpiration, cell division and so on. Phytoremediation involves several plant species which have the ability to accumulate or degrade contaminants, including heavy metals. Another important strategy is the utilization of transgenic plants transformed with bacterial mer genes to increase phytoremediation of mercury. The mercury-resistant plant growth promoting microbes (PGPM) enhance plant growth under mercury stress as well as increase the mercury uptake by plants. This chapter summarizes the present understanding toward the mercury toxicity and their molecular responses in plants. It also illustrates the plethora of mechanism adapted by PGPM for plant growth promotion and detoxification of mercury. It also highlights the paradigms for synergistic use of PGPM for improved phytoremediation of mercury from agricultural lands.
KeywordsMercury Mercury hyperaccumulators Mer genes Plant growth promotion PGPM-assisted phytoremediation
The author I. Gontia-Mishra acknowledges the funding provided by Science and Engineering Research Board, New Delhi, India, grant number PDF/2017/001001.
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