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Molecular Plant Pathology

Requirement of the Common Region of DNA-B and the BL1 Open Reading Frame of Bean Golden Mosaic Geminivirus for Infection of Phaseolus vulgaris. Denise R. Smith, Department of Plant Pathology, University of Wisconsin, Madison 53706; Douglas P. Maxwell, Department of Plant Pathology, University of Wisconsin, Madison 53706. Phytopathology 84:133-138. Accepted for publication 25 October 1993. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/Phyto-84-133.

Infectious clones of bean golden mosaic geminivirus (BGMV) can be inoculated onto the economically important host Phaseolus vulgaris, causing a reaction indistinguishable from that seen in the field. To elucidate the functions of the BGMV genome in beans, six clones, each with a point mutation, insertion, or deletion in the common region or BL1 open reading frame (ORF) of DNA-B of BGMV (Guatemalan isolate), were constructed. These clones were coinoculated with wild-type DNA-A of BGMV into bean radicles (P. vulgaris) by particle acceleration to determine the effect of the mutations on infectivity. Four mutants caused symptoms ranging from very mild mosaic to wild-type mosaic. Two mutants did not cause systemic infection: one that should have produced a truncated BL1 protein and another in which a 74-nucleotide section of the common region, including a putative stem-loop, was removed. We conclude that the BL1 ORF and the area of the DNA-B common region containing the putative stem-loop are required for systemic infection of P. vulgaris.