Roles of Plant Small RNAs in Biotic Stress Responses

Abstract

A multitude of small RNAs (sRNAs, 18-25 nt in length) 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. Besides their roles in developmental patterning and maintenance of genome integrity, sRNAs are also integral components of plant responses to adverse environmental conditions, including biotic stress. Until recently, antiviral RNA silencing was considered a paradigm of the interactions linking RNA silencing to pathogens: Virus-derived sRNAs silence viral gene expression and, accordingly, viruses produce suppressor proteins that target the silencing mechanism. However, increasing evidence shows that endogenous, rather than pathogen-derived, sRNAs also have broad functions in regulating plant responses to various microbes. In turn, microbes have evolved ways to inhibit, avoid, or usurp cellular silencing pathways, thereby prompting the deployment of counter-defensive measures by plants, a compelling illustration of the never-ending molecular arms race between hosts and parasites.

Identification of Potential microRNAs and Their Targets in Brassica rapa L.

“…Since the discovery of plant miRNAs in, 2002 (Llave et al, 2002b), miRNAs have become an important and integral topic in functional genomic research; consequently, several studies show that miRNAs are important regulatory elements involved in plant development, metabolism, biotic and abiotic stresses, and many other functions (Lu et al, 2005;Pulido and Laufs, 2010;Ruiz-Ferrer and Voinnet, 2009;Zhang et al, 2006a;2007c). B. rapa is an important crop with varying leaf and plant morphophytes.…”

Botrytis small RNA Bc-siR37 suppresses plant defense genes by cross-kingdom RNAi

“…8,16,5 Small RNAs (sRNAs), such as small interfering RNAs (siRNAs) and microRNAs (miRNAs) that trigger RNA interference (RNAi) are important in regulation and fine-tuning of plant immunity genes. 26,19,35 Several plant endogenous siRNAs and miRNAs contribute to the regulation of PTI, such as Arabidopsis miR393, miR160, and miR167; 22,37 ETI, such as natural antisense (nat)-siR-NAATGB2, 20 Arabidopsis long-siRNA-1, 18 and miRNA863-3p 23 ; or both PTI and ETI, as in the case of miR393 Ã . 38 Even though the regulatory role of endogenous plant sRNAs in plant immunity has been well characterized, little is known about the role of pathogen-derived sRNAs in microbial pathogenicity and host adaptation.…”

Biotech Potatoes in the 21st Century: 20 Years Since the First Biotech Potato

“…Plant microRNAs (miRNAs) are short (20-24 nucleotides), non-coding RNA molecules important in posttranscriptional regulation of gene expression. Hundreds of endogenous plant miRNAs have been identified and can have wide-ranging effects on plant development, abiotic and biotic stress responses, protein turnover, and signaling through the regulation of specific genes, many of which are transcription factors (reviews by Zhang et al 2006;Ruiz-Ferrer and Voinnet 2009). In potato, hundreds of miRNAs have been identified (Zhang et al , 2013Yang et al 2010;Kim et al 2011;Xie et al 2011).…”