Endophytic Fungi Piriformospora indica Mediated Protection of Host from Arsenic Toxicity.

Shayan Mohd,Jagriti Shukla,Ram Narayan,Jai Shankar,Prem N Saxena,Manoj Kumar,Nidhi Arjaria,Somendu K Roy,Kapil Mandrah,Aparna S Kushwaha

doi:10.3389/fmicb.2017.00754

Abstract

Complex intercellular interaction is a common theme in plant-pathogen/symbiont relationship. Cellular physiology of both the partners is affected by abiotic stress. However, little is known about the degree of protection each offers to the other from different types of environmental stress. Our current study focused on the changes in response to toxic arsenic in the presence of an endophytic fungus Piriformospora indica that colonizes the paddy roots. The primary impact of arsenic was observed in the form of hyper-colonization of fungus in the host root and resulted in the recovery of its overall biomass, root damage, and chlorophyll due to arsenic toxicity. Further, fungal colonization leads to balance the redox status of the cell by adjusting the antioxidative enzyme system which in turn protects photosynthetic machinery of the plant from arsenic stress. We observed that fungus has ability to immobilize soluble arsenic and interestingly, it was also observed that fungal colonization restricts most of arsenic in the colonized root while a small fraction of it translocated to shoot of colonized plants. Our study suggests that P. indica protects the paddy (Oryza sativa) from arsenic toxicity by three different mechanisms viz. reducing the availability of free arsenic in the plant environment, bio-transformation of the toxic arsenic salts into insoluble particulate matter and modulating the antioxidative system of the host cell.

Highlights

Cellular metabolism shapes the phenotypes of cells/organism
It was observed that pre-colonization of P. indica in paddy plant is a time dependent process and is unaffected by arsenic salt concentration that is otherwise toxic to plants
Almost all terrestrial plants make an association with arbuscular mycorrhizal fungi (AMF) except a limited number of plant, resulting in a range of beneficial consequences to their hosts

Summary

Introduction

Cellular metabolism shapes the phenotypes of cells/organism. Kinetic changes in cellular metabolism provide flexibility and robustness for adaptability in response to environmental cues. The changes are much more evident when cells are challenged either with toxic doses of chemicals or in response to infectious virus, fungi, and bacteria. The interaction becomes much more complex when both the biotic and abiotic factors act in collusion. Heavy anthropological and geological activities are a major contributor of toxic products in nature. The toxicants, in turn, pose a serious risk to health and environment when they end up at the top of the food chain after being taken up by the plants. Toxicity of the harmful chemical largely depends on the geological and biological activities that determine the free availability of the toxic ions. Metal and metalloid toxicity is a serious environmental and health issue.

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Results

Conclusion