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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Cereal Crops Research » Research » Publications at this Location » Publication #321067
Title: ORF43 of Maize rayado fino virus is dispensable for systemic infection of maize and transmission by leafhoppers

Author
item Edwards, Michael
item Weiland, John
item Todd, Jane
item Stewart, Lucy
item Lu, Shunwen

Submitted to: Virus Genes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/2/2016
Publication Date: 2/2/2016
Publication URL: http://handle.nal.usda.gov/10113/62152
Citation: Edwards, M.C., Weiland, J.J., Todd, J., Stewart, L.R., Lu, S. 2016. ORF43 of maize rayado fino virus is dispensable for systemic infection of maize and transmission by leafhoppers. Virus Genes. 52:303-307.

Interpretive Summary: Viruses generally have very compact genomes and therefore have evolved various mechanisms to encode all of the genes needed within those compact genomes. One such mechanism is to express two different genes from the same RNA sequence by translating them from different reading frames. Maize rayado fino virus (MRFV) possesses such an overlapping gene or open reading frame (ORF) encoding a protein with a predicted mass of 43 kDa (ORF43) that has been postulated to be a viral movement protein (a protein that helps the virus move through the infected plant). To test this, we introduced mutations designed to prevent the expression of ORF43. Inoculation of maize seed resulted in plants that exhibited symptoms typical of MRFV infection for all mutants tested. Furthermore, corn leafhoppers transmitted the virus mutants to healthy plants at a frequency similar to that for wild type MRFV. Viral RNA recovered from plants infected with mutants both prior to and after leafhopper transmission retained mutations blocking ORF43 expression. The results indicate that ORF43 of MRFV is dispensable for both systemic infection of maize and transmission by leafhoppers.

Technical Abstract: Maize rayado fino virus (MRFV) possesses an open reading frame (ORF) encoding a protein with predicted mass of 43 kDa (ORF43) that has been postulated to be a viral movement protein. Using a clone of MRFV (pMRFV-US) from which infectious RNA can be produced, point mutations were introduced to either prevent initiation from three potential AUG initiation codons near the 5’-end of ORF43 or prematurely terminate translation of ORF43. Inoculation of maize seed via vascular puncture inoculation (VPI) resulted in plants exhibiting symptoms typical of MRFV infection for all mutants tested. Furthermore, corn leafhoppers (Dalbulus maidis) transmitted the virus mutants to healthy plants at a frequency similar to that for wild type MRFV-US. Viral RNA recovered from plants infected with mutants both prior to and after leafhopper transmission retained mutations blocking ORF43 expression. The results indicate that ORF-43 of MRFV is dispensable for both systemic infection of maize and transmission by leafhoppers.