Expression of microRNAs and their targets regulates floral development in tobacco (Nicotiana tabacum).

MicroRNAs (miRNAs) are an extensive class of endogenous posttranscriptional gene regulators that function to mediate gene expression by cleaving target mRNAs or by preventing protein translation. Because of their importance in mediating gene regulation, identifying and elucidating the function of miRNAs have been the primary focus of many researchers. Now that many miRNAs have been identified and assessed for their functionality, the next step is to create expression profiles for miRNAs, so that gene expression studies can be further enhanced with knowledge of the basal expression levels of miRNAs and their targets. In a previous study, 259 putative miRNAs were identified in tobacco, in which 11 of them were confirmed. The primary goal of this study was to further expand on that study and create an expression profile for nine miRNAs and their targets in a tissue-specific manner in tobacco. We chose to study miRNAs that largely play a role in floral development and nutrient stress response. The results of our study show that all tested miRNAs and their targets were expressed in a differential manner. The results of our study also show that out of the tested miRNAs and their targets, miR159, miR157, miR167, miR172, and superoxide dismutase were expressed the highest, suggesting that these genes may play a vital role in the growth and development of tobacco. Corrected expression of miRNAs and their targets regulates floral development.