|Chaouch, R - OHIO STATE UNIVERSITY|
|Hogenhout, S - OHIO STATE UNIVERSITY|
Submitted to: International Congress of Plant Pathology Abstracts and Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: July 29, 2002
Publication Date: February 3, 2003
Citation: Gingery, R.E., Chaouch, R., Redinbaugh, M.G., Hogenhout, S.A. 2003. Genetic variability in maize chlorotic dwarf virus. International Congress of Plant Pathology Abstracts and Proceedings. Vol. 2. p. 245. Technical Abstract: Maize chlorotic dwarf virus (MCDV) (genus Waikavirus; family Sequiviridae) is a picorna-like virus transmitted by the black-faced leafhopper, Graminella nigrifrons, in a semi-persistent manner using a virus-encoded helper protein. The MCDV genome contains one large open reading frame encoding a polyprotein that is subsequently cleaved by proteases into an unknown number of individual viral proteins. Two MCDV isolates (MCDV-OH (Ohio) and MCDV-TN (Tennessee)) were previously sequenced. In this study, two other isolates (MCDV-S (severe) and MCDV-M1) were sequenced to obtain additional information about genetic variability within this group. The nucleotide and deduced amino acid sequences of MCDV-OH and MCDV-S were both >99% identical. The specific alterations contributing to the differences in symptom severity are unknown. The high level of sequence identity between these two isolates clearly identifies them as strains of the same virus. On the other hand, the sequences of MCDV-TN, MCDV-OH, and MCDV-M1 are more highly divergent. MCDV-M1, an isolate which causes mild symptoms by itself, but acts synergistically with other MCDV isolates to produce severe symptoms, had only 59% nucleotide sequence identity with MCDV-OH and 68% with MCDV-TN. MCDV-OH and MCDV-TN were 58% identical. The deduced amino acid sequence comparisons were comparable. Overall, MCDV-M1 had 61% amino acid identity with MCDV-OH and 74% with MCDV-TN; MCDV-OH and MCDV-TN were 61% identical. However, several highly conserved regions were identified. MCDV-OH, MCDV-M1, and MCDV-TN share the same vector, are serologically related, and have overall genomic similarity. However, based on sequence analysis, they may represent three distinct virus species.