Recent Perspectives on Cross Talk Between Cadmium, Zinc, and Arbuscular Mycorrhizal Fungi in Plants

Soils polluted with heavy metals result into various environmental and ecological tribulations like alterations in microbial community, deterioration of soil, and induction of metals into the human food chain. Noxious heavy metals, for instance, cadmium (Cd) and essential micronutrients like zinc (Zn) have identical chemical properties and are normally taken up by plants via similar carrier proteins as those of indispensable micronutrients. Cohesive interactions between plants and microbes and their co-existence or struggle for survival play a fundamental role in acclimatizing to metal-polluted environments. In this context, arbuscular mycorrhizal (AM) fungi are regarded as a prospective biotechnological approach for increasing tolerance of plants to heavy metal-polluted soils. However, the vital molecular factors responsible for regulating metal homeostasis/balance in these microbes have been poorly understood. Moreover, combined studies assessing the effect of AM fungal inoculation in alleviating Cd and/or Zn toxicity in plants and the underlying mechanisms are still unclear. This review presents the updated information on cross talk between Cd–Zn–AM in plants grown on agricultural and metal-contaminated soils.