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
Crown gall disease is an agricultural problem caused by the soil-borne bacterium,
Agrobacterium tumefaciens. A. tumefaciens oncogenes cause transformed plant cells
to overproduce the hormones, auxin and cytokinin. High hormone levels cause
unorganized plant cell growth resulting in a gall. Control of crown gall disease is
difficult because after plant...
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...
Vaccinia virus (VV) is a large DNA virus belonging to the Orthopoxvirus
family. The viral replicative life cycle takes place solely within the cytoplasm
of a mammalian host cell. The VV genome contains 196 open reading frames
which are expressed in a highly regulated and temporal fashion in order to...
The phytohormones auxin and cytokinin control plant development through a complex network of interactions which include synergistic, additive, and opposite effects whose mechanisms are unknown. The auxin-insensitive diageotropica (dgt) mutant provided a tool to dissect the relationship between auxin- and cytokinin-induced responses in tomato. Morphological, physiological, and molecular data support...
The plant hormone auxin regulates many aspects of plant growth and
development. At the cellular level, auxin can stimulate cell division, cell elongation, and
cell differentiation. Little is known about the molecular mechanisms that mediate auxin
action at this level, although changes in gene expression have been implicated in each...
Plant growth, development, and environmental responsiveness are
dependent on hormone-induced gene expression. This dissertation reports
multiple interactions between the plant hormones auxin and ethylene and
investigates their contribution to the gravitropic response, elongation
growth, adventitious root formation, callus and tracheary element initiation
and growth, and flower development.
Four mutants of...