Abstract
Modulation of gene expression through RNA interference is well conserved in eukaryotes and is involved in many cellular processes. In the oomycete Phytophthora, research on the small RNA machinery and function has started to reveal potential roles in the pathogen, but much is still unknown. We examined Argonaute (AGO) homologs within oomycete genome sequences, especially among Phytophthora species, to gain a clearer understanding of the evolution of this well-conserved protein family. We identified AGO homologs across many representative oomycete and stramenopile species, and annotated representative homologs in P. sojae. Furthermore, we demonstrate variable transcript levels of all identified AGO homologs in comparison to previously identified Dicer-like (DCL) and RNA-dependent RNA polymerase (RDR) homologs. Our phylogenetic analysis further refines the relationship of the AGO homologs in oomycetes and identifies a conserved tandem duplication of AGO homologs in a subset of Phytophthora species.
Highlights
The RNA interference (RNAi) machinery, including Argonaute (AGO) proteins, is well conserved among most eukaryotic supergroups (Cerutti and Casas-Mollano, 2006)
To infer the evolutionary history of Phytophthora AGO homologs, we conducted a phylogenetic analysis of AGO homologs including species selected across the Chromalveolate supergroup and representatives of eukaryote AGO-like and PIWI-like homologs, including an Archaea PIWI-like homolog as an outgroup (Figure 1)
Oomycete AGO homologs formed a separate group with AGO-like homologs from C. elegans, humans, and Arabidopsis
Summary
The RNA interference (RNAi) machinery, including Argonaute (AGO) proteins, is well conserved among most eukaryotic supergroups (Cerutti and Casas-Mollano, 2006). The N-domain has been shown to be required for unwinding of the small RNA duplex in the process of forming the mature RISC complex (Kwak and Tomari, 2012) and in some AGOs it is required for cleavage of the target mRNA (Hauptmann et al, 2013). The MID domain binds the 5 nucleotide of the guide sRNA (Frank et al, 2010, 2012), which, in addition to the structure of the small RNA duplex, is important for the binding specificity seen in some AGOs (Tomari et al, 2007; Jannot et al, 2008; Czech et al, 2009; Okamura et al, 2009; Ghildiyal et al, 2010).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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.
