Six plant pathogenic isolates of Pseudomonas
syringae pv. glycinea, the causal agent of bacterial
blight of Glycine max (L.) Merrill, and one isolate of
P. syringae pv. phaseolicola, the causal agent of halo
blight of Phaseolus vulgaris L., have been examined for
the presence of circular duplex deoxyribonucleic acid
(DNA)....
A pathogenicity locus of Pseudomonas syringae pv.
syringae identified by Tn5 mutagenesis was investigated.
The mutant strain PS9024 is attenuated for disease
expression in its host, Phaseolus vulgaris, but produces
the hypersensitive reaction (HR) in the nonhost, tobacco
(Nicotina tabacum). A cosmid clone carrying 16 kilobases
(kb) of contiguous genomic...
1S801 is a transposable element isolated from Pseudomonas syringae pathovar
(pv.) phaseolicola, the causal agent of halo blight of bean. Fragments of the element are
present in multiple copies on an indigenous plasmid, pMMC7105, of strain LR781, and
have been implicated as sites of homologous recombination leading to imprecise
excision...
Inbreeding of the avirulent physiologic race 8 strains of Ustilago hordei was
purported to have increased its pathogenicity in a stepwise manner that led to a highly
pathogenic race, designated race 14. The analysis of electrophoretic karyotypes and
restriction fragment length polymorphism profiles detected with a telomere-specific probe
(TelomereRFLP) in...
Five strains of the bean pathogen Pseudomonas syringae pv.
phaseolicola were analyzed for plasmid number, size, and relatedness.
Each strain contained one or two indigenous plasmids which ranged in
size from 6.8 to 151 kbp. BamHI and EcoRI restriction patterns revealed that total plasmid DNA from each strain had a...
Electrophoretic karyotypes were obtained from intact cells of four wild
type strains of Tilletia caries and T. controversa, and 5 inter specific hybrid
progeny using clamped homogeneous electric field, pulsed field gel
electrophoresis (CHEF PFGE). Each karyotype was polymorphic and unique
relative to the other strains. However, the relative size...
Experiments were performed to assess regulatory factors governing maize
embryo maturation and vivipary. Both visual and molecular markers of embryo
development were used to examine the roles of the hormones abscisic acid (ABA)
and gibberellins (GAs), as well as water stress in governing transit from early
embryogeny to maturation-phase development....
Maize defective kernel (dek) mutants identify genes necessary for the
successful passage of embryos through the embryogenic and maturation
phases of embryo development. The goal of this thesis was to characterize the
developmental potential of three dek mutants that appeared to be
morphologically blocked prior to the maturation phase of...
Attempts to develop dual-purpose durum wheat cultivars for both pasta and bread-making
have been unsuccessful. To better understand this limitation, thirty durum
genotypes, selected based on their diverse geographical origin, and five bread wheat
cultivars were compared as to their flour mixing properties, dough physical characteristics
and baking performance. The...