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|Title:||The Genome of Bean Golden Mosaic Virus: Restriction Map and Use as a Probe to Sensitively Diagnose Geminivirus Infection|
|Author(s):||Haber, Stephen Michael|
|Department / Program:||Plant Pathology|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Subject(s):||Agriculture, Plant Pathology|
|Abstract:||The organization of the genome of bean golden mosaic virus (BGMV) is presented as a model for whitefly-transmitted geminiviruses. The twin-sphere 'geminate' particle is the unit particle and contains one molecule of circular, single-stranded (ss) DNA about 2600 bases long. Linear forms of the DNA, of unimodal size distribution and slightly shorter than the circular form, most likely arise from the circular form by random breakage. The results of restriction analyses and studies of dose/infection relationships in bean protoplasts inoculated with BGMV DNA suggest that the genome is divided between two components encapsidated in separate geminate particles.
A restriction site map, obtained by analysis of double digestions of double-stranded (ds) BGMV-specific DNA and of clones of the larger restriction fragments, is consistent with the divided genome model. Hybridization analysis, using probes made from one or the other of two BGMV DNA species separated by prolonged agarose gel electrophoresis, shows that most of the components' sequences show little homology to each other except for a unique, short (ca. 200 base) region on each component showing high homology to its counterpart on the other component.
The specific DNA-DNA hybridization methods used to study the BGMV genome can be applied to detect and characterize related DNA species extracted in crude form from plant tissues infected with other known or suspected geminiviruses. The characteristic "fingerprints" formed by the sets of specifically-hybridizing restriction fragments demonstrate that BGMV infects Malvastrum coromandelianum, a malvaceous weed hitherto unsuspected as a host. Fingerprint analysis also shows that isolates of BGMV from Puerto Rico and Venezuela are related, but distinct strains. The sensitivity, relative ease and rapidity of fingerprint analysis make it feasible to pursue seemingly superficial clues, such as the presence of symptoms resembling those of known geminivirus diseases. An example is the finding of specifically hybridizing fragments summing to about 5000 basepairs in leaves from hackberry (Celtis occidentalis) trees afflicted with island chlorosis.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1983.
|Date Available in IDEALS:||2014-12-15|