Tapping RNA silencing pathways for plant biotechnology

Abstract

SummaryPlants have evolved a variety of gene silencing pathways mediated by small RNAs.Mostly 21 or 24 nt in size, these small RNAs repress the expression of sequence homologous genes at the transcriptional, post-transcriptional and translational levels.These pathways, also referred as RNA silencing pathways, play important roles in regulating growth and development as well as in response to both biotic and abiotic stress. Although the molecular basis of these complicated and interconnected pathways has become clear only in recent years, RNA silencing effects were observed and utilized in transgenic plants early in the plant biotechnology era, more than two decades ago. Today, with a better understanding of the pathways, various genetic engineering approaches have been developed to apply RNA silencing more effectively and broadly. In addition to summarizing the current models of RNA silencing, this review discusses examples of its potential uses and related issues concerning its application in plant biotechnology.

Sequence-specific protein aggregation generates defined protein knockdowns in plants

“…This method has several potential advantages in respect to known knockdown approaches that act at the genomic or transcriptional level, such as T-DNA or transposon insertions and RNA-mediated gene suppression (RNA interference [RNAi], artificial microRNA, and antisense RNA) that can often suffer from significant drawbacks, such as off-target effects or systemic silencing. Additionally, sensitivity to environmental and developmental stresses and the observed trait instability also affect the efficiency of the RNA-silencing technology (Small, 2007;Frizzi and Huang, 2010). The APR peptides can also be expressed over several generations without silencing, therefore overcoming the phenotypic instability of the RNAi technology.…”

Posttranscriptional gene silencing in nuclei

“…siRNA-based gene silencing is increasingly being used for crop improvement (11). Soybeans can be engineered to produce oil with low levels of polyunsaturated fatty acids through a reduction of FAD2, a fatty acyl Δ12 desaturase.…”

Gene Duplication and RNA Silencing in Soybean

“…An alternative approach to suppress gene expression in plants is the use of artificial miRNAs ( Figure 4) (amiRNAs; also called synthetic miRNAs) [38,126]. This approach involves modification of plant miRNA sequence to target specific transcripts, originally not under miRNA control, and downregulation of gene expression via specific cleavage of the target RNA.…”

“…It can also be used as a tool for analyzing specific gene functions and producing new features in organisms including plants [36][37][38]. Engineering novel traits through RNA silencing in soybean has been done using transgenes or virus vectors (Figure 1).…”