Abiotic Stress-Responsive Small RNA-Mediated Plant Improvement under a Changing Climate

Small, non-coding RNAs are a distinct class of regulatory RNAs in plants and animals that control a variety of biological processes. In plants, several classes of small RNAs with specific sizes and dedicated functions have evolved through a series of pathways. The major classes of small RNAs include microRNAs (miRNAs) and small interfering RNAs (siRNAs), which differ in their biogenesis. miRNAs control the expression of cognate target genes by binding to reverse complementary sequences, resulting in cleavage or translational inhibition of the target RNA. siRNAs have a similar structure, function, and biogenesis as miRNAs, but are derived from long double-stranded RNAs and can often direct DNA methylation at target sequences. Environmental stress factors such as drought, elevated temperature, salinity, and rising carbon dioxide (CO 2) levels affect plant growth and pose a growing threat to sustainable agriculture. This has become a hot issue due to concerns about the effects of climate change on plant resources, biodiversity, and global food security. Besides the roles of small RNAs in growth, development, and maintenance of genome integrity, small RNAs are also important components in plant stress responses. One way in which plants respond to environmental stress is by modifying their gene expression through the use of small RNAs. Thus, understanding how small RNAs regulate gene expression will enable researchers to explore the role of small RNAs in abiotic stress responses for adapting to climate change. Here, we present an overview of small RNA-mediated plant improvement under a changing climate.