Physiological and molecular insights into rice-arbuscular mycorrhizal interactions under arsenic stress

The symbiotic associations between plants, microbes and fungi are examples of living in harmony. The intimate association between the arbuscular mycorrhizal fungi (AMF) and their host plants benefits the latter in nutrient (viz., phosphate, nitrogen etc.) acquisition in exchange of carbohydrates. Arsenic (As) accumulation in rice grains has become a serious issue in some parts of world having high As levels in soil and groundwater. To this end, experiments have demonstrated ameliorative potential of AMF colonization on As stress in rice. AMF colonization not only influences As concentrations in grains but also the speciation of As and reduces the ratios of inorganic/organic As concentrations. Positive influences of AMF colonization have also been linked to alteration in transport of As and phosphate, photosynthetic reactions and improved growth. A role of 14-3-3 proteins in AMF colonization under As stress is also suggested in recent studies. Importantly, grain yield has been found to increase in presence of AMF colonization. In this review, we discuss the molecular intricacies of rice-AMF in the context of As stress.