ABSTRACT
Genetically engineered plants have varied applications in agriculture for enhancing the values of food and feed.Genetic engineering aims to introduce selected genetic regions with desirable traits into target plants for bothspatial and temporal expressions. Promoters are the key elements responsible for regulating gene expressionsby modulating the transcription factors (TFs) through recognition of RNA polymerases. Based on theirrecognition and expression, RNA polymerases were categorized into RNA pol II and pol III promoters.Promoter activity and specificity are the two prime parameters in regulating the transgene expression. Since theuse of constitutive promoters like Cauliflower mosaic virus (CaMV) 35S may lead to adverse effects on nontarget organisms or ecosystem, inducible/tissue specific promoters and/or the RNA pol III promoters providemyriad opportunities for gene expressions with controlled regulation and with minimum adverse effects.Besides their role in transgene expression, their influence in synthetic biology and genome editing are alsodiscussed. This review provides an update on the importance, current prospects, and insight into the advantagesand disadvantages of promoters reported thus far would help to utilize them in the endeavour to developnutritionally and agronomically improved transgenic crops for commercialization.