Role of Small RNAs in Plant Immunity

Abstract

Small RNAs play a crucial role in the regulation of gene expression, operating at both the transcriptional and post-transcriptional stages. These molecules have the ability to initiate target destruction or block translation. The activation of plant immunity is frequently associated with the increased expression of growth-regulatory microRNAs (miRNAs) following the detection of pathogens. Additionally, conserved miRNAs play a crucial role in regulating auxin signaling. Plants are capable of generating two distinct categories of short RNA molecules, namely microRNAs and small interfering RNAs. Three highly prevalent miRNA families induce the generation of secondary siRNAs from 74 out of the 79 NLR transcripts that produce siRNAs. This phenomenon highlights the appeal of employing secondary siRNA-mediated control as a viable technique. Two microRNAs (miRNAs) derived from plants have been found to target virulence genes in the fungal disease Verticillium dahliae. Additionally, it has been observed that secondary small interfering RNAs (siRNAs) can increase plant protection by facilitating host-induced gene silence. TasiRNAs have been observed to exhibit enhanced mobility and resilience in the context of non-cell-autonomous silencing. The production and function of short RNAs in fungal and oomycete infections have been minimally investigated. Verticillium dahliae, has been seen to make small RNAs (sRNAs) that range in size from 18 to 25 nucleotides (nt) without a preference for one size over the other. Additionally, a specific microRNA (miRNA) known as VdmilR1, measuring 21 nt in length, has been thoroughly studied and its functional characteristics have been elucidated. Phytophthora species, which are filamentous eukaryotic microbes, have been found to inflict substantial economic losses in the fields of agriculture and forestry. RNA interference (RNAi) has the potential to regulate the expression of neighboring effector genes by inducing the creation of heterochromatin. In plants, the movement of small RNAs has been observed both locally and across extended distances. These small RNAs have the potential to enhance plant defense mechanisms against nonviral diseases by acting as systemic signaling molecules. The domain of sRNAs in plant-pathogen/parasite interactions has experienced significant advancements; nonetheless, numerous obstacles remain in the realm of trans-species gene silencing that require more investigation.