Crosstalk between plant miRNA and heavy metal toxicity

Abstract

Plants have the ability to survive under excess and hampered nutrient supply. Heavy metal (HM) stress considerably reduces the growth of plants and ultimately proves to be the most limiting factor toward sustainable crop production. Essential and non-essential metals both fall in this category. MicroRNA (miRNA) participates in mediating posttranscriptional regulation through the mechanism of cleaving transcripts or through translational inhibition. So, it is obvious that the study of these miRNAs can be used as a tool to improve tolerance of plants against different environmental stresses. With the help of next-generation sequencing, the structures and functions of these miRNAs have been studied in detail with their different functions and roles in several plants facing stressed conditions. These miRNAs are modulators of plant responses in case of heavy metal stress. Data related to metal-responsive miRNAs of plants grown under metal stress showed that miRNAs activate some genes or transcription factors that ameliorate the toxic effects of metals and thus acts in detoxification. Working as systematic signals, these are also found to be involved in some physiological mechanisms that stimulate plants to show responses under imposed metal stresses. On the other hand, using above-mentioned approaches, miRNAs proved a very helpful, programmatic, and reasonable technique. Earlier, the use of miRNA technique was practiced to engineer tolerance in plants against heavy metal stress. Thus, we need to augment our knowledge about multifarious functions of miRNAs in HM stresses. This chapter throws light on the importance of miRNAs in the enhancement of HM stress tolerance and their functions in amelioration of HM-caused toxicity. This chapter also deals with the functions of miRNAs with respect to different metals and functions of different metal-responsive miRNAs.