Aphid Transmission, Replication, and Transcription of BYDV -Pav -Il and Genome Organization of RhPV

Infectious full-length cDNA clones of an Illinois isolate of the PAV strain of Barley yellow dwarf virus (BYDV-PAV-IL), driven by Cauliflower mosaic virus-35S promoter (CaMV-35S), were constructed to study the mechanism of replication and transcription of BYDV-PAV-IL in oat protoplasts. Linearized wild-type and mutant cDNA clones express the 22-kDa coat protein and produced genomic and subgenomic RNAs in ratios similar to those observed in protoplasts inoculated with viral RNA. Genomic RNA regions were identified that either down-regulated promoters located 5'-proximally on positive strand RNA strands or altered the site of transcription initiation for subgenomic RNA2. Additionally, the 3' non-coding region of the BYDV-PAV-IL genome was found to be required for replication. These results illustrated that in vivo-transcribed cDNA clones can be effective tools for the analysis of the expression and replication of the BYDV-PAV genome. A Rhopalosiphum padi cDNA expression library was screened to identify aphid proteins that interact with the BYDV-PAV-IL capsid proteins using the yeast two-hybrid system. Seven clones activated the expression of the reporter genes, supposedly by interacting with capsid proteins of BYDV-PAV, but complementation tests indicated that all were false positives. Thus, other biochemical and genetic methods may be more successful for the identification of aphid proteins that interact with BYDV-PAV. The 10,011 nt sequence of the polyadenylated R. padi virus (RhPV) RNA genome was determined. The sequence contained two open reading frames (ORFs), but no subgenomic RNAs were found. The two ORFs are preceded by more than 500 nt of noncoding RNA that may facilitate the cap-independent initiation of translation. The predicted amino acid sequence of ORF1 was similar to the nonstructural proteins of several plant and animal RNA viruses. ORF2 encoded the structural proteins. This genomic organization is very similar to those of Drosophila C virus, Plautia stali intestine virus and Cricket paralysis virus . These data suggest that RhPV is a member of a unique group of small RNA viruses that infects primarily insects.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Crop Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Moon, Jae Sun

Contributors dc:contributor

• Domier, Leslie L.

• Biology, Microbiology

Language dc:language

eng

Identifier

(MiAaPQ)AAI9953092

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/85062