Virus Evolution Workgroup: 1999 Workshop Abstract

1999 Workshop Abstracts | Virus Evolution Home Page | Plant Biology Home Page

Heterogeneity in the 3'untranslated region of tobacco mild green mosaic virus from Nicotiana glauca resulting in variants with 3 or 6 pseudoknots

Martin Ngon A Yassi^{1, 2} Sohrab Bodaghi¹ and J. Allan Dodds¹¹ Dept. of Plant Pathology, University of California Riverside, Riverside, CA 92521
² Plant Biology Division, The S. R. Noble Foundation, P. O. Box 2180 Ardmore, OK 73402

Isolates of tobacco mild green mosaic tobamovirus (TMGMV) were obtained from 58 plants of Nicotiana glauca in southern California and placed in one of two groups, small type and large type based on the size of the subgenomic RNA for the coat protein (CP). The CP sequence differed by no more than one amino acid for the two types, and the small type was identical to that of the published type TMGMV. Thirty six of the isolates had a dsRNA profile that matched that of TMGMV, and the nucleotide sequence of the 3’ untranslated region (3’UTR) of six of these isolates was similar to the published sequence of TMGMV. Twenty-two isolates had a larger dsRNA fro the CP and I2 subgenomic RNAs. Six of these were sequenced and all had a repeat sequence of between 147 and 165 bases in the part of the 3’UTR that is involved in the formation of pseudoknots. Small type (type TMGMV with 3 pseudoknots) yielded twice as much virus after purification than Large types (six pseudoknots). In N. rustica, Large type but not small type gave a systemic necrosis. In N. benthamiana, Large type but not small type induced rapid wilting. In N. clevelandii, Small type but not Large type induced systemic lethal necrosis. Both Large type and Small type cross-protected against each other in N. tabacum. Almost all isolates of TMGMV used in this study were initially associated with satellite tobacco mosaic virus (STMV) and both types supported STMV in greenhouse experiments.

Abstract - Presented at the Virus Evolution Workshop
Ardmore, OK
October 21 - 24th, 1999

Virus Evolution Workshop - Main Page
Poster Presentations

To contact the organizers:
e-mail: mroossinck@noble.org

Dr. Marilyn Roossinck
Plant Biology Division
The Noble Foundation
P.O. Box 2180
Ardmore, OK 73402

phone: 580 224-6630