siRNAs Derived from Cymbidium Mosaic Virus and Odontoglossum Ringspot Virus Down-modulated the Expression Levels of Endogenous Genes in Phalaenopsis equestris

Lan, Han-hong; Wang, Cui-mei; Chen, Shuang-shuang; Zheng, Jian-ying

In BLAST2GO analysis, a total of 54 predicted target genes of CymMV and ORSV siRNAs were annotated and classified into three Gene Ontology (GO) categories (biological process, cellular component, and molecular function) (Fig. 5) . For target genes of CymMV siRNAs, five terms under the biological process section, "stress response," "defense response or innate immune responses," "protein phosphorylation," "metabolic process," and "cytoskeleton," represented 85% of the classified targets (Fig. 5A) ; the four most highly represented GO terms were "integral component of membrane," "nucleus," "myosin complex," and "proteasome" under the cellular component category, comprising 75% of the annotated genes (Fig. 5A) ; and the five most abundant GO terms under the molecular function category, "protein kinase activity," "nucleic acid binding," "ubiquitin-protein transferase activity," "DNA binding transcription factor activity," and "microtubule motor activity," represented 65% of the annotated genes (Fig. 5A) . For target genes of ORSV siRNAs, four terms under the biological process section, "fatty acid biosynthetic process," "RNAi," "cytoskeleton," and "DNA replication," represented 86% of the classified targets (Fig. 5B) ; the four most highly represented GO terms were "RNAi components," "intermediate filament," "integral component of membrane," and "DNA replication factor C complex" under the cellular component category, comprising 60% of the annotated genes (Fig. 5B) ; and the seven most 5 . Gene Ontology categories of predicted target genes of small interfering RNAs (siRNAs) derived from Cymbidium mosaic virus (CymMV) and Odontoglossum ringspot virus (ORSV) in Phalaenopsis equestris. The predicted target genes were subject to BLAST alignment and Gene Ontology annotation using BLAST2GO software. A and B denoted respectively the predicted genes targeted by siRNAs derived from CymMV and ORSV in P. equestris. RNAi, RNA interference. abundant GO terms under the molecular function category, "binding", "oxidoreductase activity," "siRNA metabolic process," "structural molecule activity," "hydrolase activity," "regulation of transcription," and "protein kinase activity", represented 83% of the annotated genes (Fig. 5B) . Thus, there are some similar and different GO categories when compared with target genes of CymMV siRNAs (Fig. 5B ).