RNAi: Machinery and role in pest and disease management

Abstract

RNA interference (RNAi) is a homology-dependent gene silencing technology that is initiated by double stranded RNA (dsRNA). A multitude of small RNAs accumulate in plant tissues, although heterogeneous in size, sequence, genomic distribution, biogenesis, and action, most of these molecules mediate repressive gene regulation through RNA silencing. Micro and small interfering RNAs represent small RNA families that are recognized as critical regulatory species across the eukaryotes. Besides their roles in developmental patterning and maintenance of genome integrity, small RNAs are also integral components of plant responses to adverse environmental conditions, including biotic stress. Recent studies broaden the role of RNAi, and many successful examples have described the application of RNAi for engineering plant resistance against a range of prokaryotic and eukaryotic organisms. Expression of dsRNA directed against suitable pathogen and insect genes in transgenic plants showed protection against pests, opening the way for a new generation of pest and disease resistant crops. Here, current knowledge on the uptake mechanisms of dsRNA in plant pests and the potential of RNAi to control pest and pathogen is described. Concerns regarding further research on dsRNA uptake mechanisms and the promising application possibilities for RNAi in pest and disease management have been discussed. Further, the progress of RNAi-based transgenic plant resistance against eukaryotic pests, as well as future challenges and prospects are addressed.