Abstract
Non-coding small RNAs (sRNA) act as mediators of gene silencing and regulate plant growth, development and stress responses. Early insights into plant sRNAs established a role in antiviral defense and they are now extensively studied across plant–microbe interactions. Here, sRNA sequencing discovered a class of sRNA in rice (Oryza sativa) specifically associated with foliar diseases caused by Xanthomonas oryzae bacteria. Xanthomonas-induced small RNAs (xisRNAs) loci were distinctively upregulated in response to diverse virulent strains at an early stage of infection producing a single duplex of 20–22 nt sRNAs. xisRNAs production was dependent on the Type III secretion system, a major bacterial virulence factor for host colonization. xisRNA loci overlap with annotated transcripts sequences, with about half of them encoding protein kinase domain proteins. A number of the corresponding rice cis-genes have documented functions in immune signaling and xisRNA loci predominantly coincide with the coding sequence of a conserved kinase motif. xisRNAs exhibit features of small interfering RNAs and their biosynthesis depend on canonical components OsDCL1 and OsHEN1. xisRNA induction possibly mediates post-transcriptional gene silencing but they do not broadly suppress cis-genes expression on the basis of mRNA-seq data. Overall, our results identify a group of unusual sRNAs with a potential role in plant–microbe interactions.
Highlights
Non-coding small RNAs act as mediators of gene silencing and regulate plant growth, development and stress responses
Small RNA sequencing of rice leaves infected with Xanthomonas oryzae pv. oryzae (Xoo) BAI3 identifies small RNAs (sRNA) loci that are upregulated in a T3SS‐dependant manner
The discovery of Xanthomonas-induced small RNAs (xisRNAs) prompted an examination of rice genetic requirement for their biogenesis. xisRNA production appears to utilize host regulatory small RNA synthesis pathways components OsDCL1 and OsHEN1 but not OsDCL4 (Fig. 5)
Summary
Non-coding small RNAs (sRNA) act as mediators of gene silencing and regulate plant growth, development and stress responses. SRNAs are typically 20–24 nucleotides (nt) in size and derive from a double stranded RNA (dsRNA) precursor that is diced into a single or multiple distinct sRNA duplexes by Dicer-like proteins (DCL). Several major classes of endogenous plant regulatory sRNAs have been defined based on the specifics of their biogenesis pathways and their mode of action[3, 5]: Micro RNAs (miRNAs) are arguably the best characterized class of sRNAs. Hairpins of MIRNA gene transcripts (pri-miRNA) are cleaved and diced by the plant DCL1 protein to generate a single miRNA duplex. This family includes Receptor-Like Cytoplasmic Kinases (RLCKs) that lack the transmembrane and extracellular domains and function intracellularly as substrates of receptor-kinase complexes for signal t ransduction[11]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
