Please check these useful links and pdf attachments for the said query.

http://www.sciencedirect.com/science/article/pii/S0012160605007645

http://www.nature.com/articles/srep21577

https://plantmethods.biomedcentral.com/articles/10.1186/1746-4811-3-12

Goof Luck

Please check these links also.

https://www.researchgate.net/post/What_is_the_best_way_to_overexpress_miRNAs

http://jxb.oxfordjournals.org/content/61/9/2271.long

http://bmcplantbiol.biomedcentral.com/articles/10.1186/s12870-015-0413-9

http://www.protocol-online.org/biology-forums-2/microRNA.html

http://journal.frontiersin.org/article/10.3389/fpls.2015.00099/full

https://www.researchgate.net/publication/268380733_Advance_On_Detect_Methods_of_Plant_Microrna_Expression

Article Advance On Detect Methods of Plant Microrna Expression

@Arvind Singh Thank you very much.