A
ripening fruit undergoes many processes,
including the production of ethylene,
chlorophyll degradation, a loss of flesh
firmness, and an increase in sugar content.
Chlorophyll catabolism (de-greening) is
significant because of its economic
importance related to shelf life and taste
of the fruit. Ethylene indirectly controls
this process by regulating genes coding for
components associated with the light
reactions of photosynthesis. Of these
components, the chlorophyll a/b-binding
(CAB) proteins have been most extensively
studied. This family of proteins serves a
wide variety of purposes, including the regulatory function of light energy
direction in the photosystems and the
protection of light harvesting complexes
upon exposure to intense light.
Jonathan Gilkerson,
undergraduate research student from
2002-2004, in collaboration with Dr. Carole
Basset (Appalachian Fruit Research Station,
Kearneysville, WV) studied ethylene
regulation of CAB expression. He evaluated
CAB expression in Arabidopsis plants transiently
transformed by particle
bombardment, and stably transformed tomato
plants using a DNA construct composed of the
regulatory region of the CAB gene (promoter)
fused to a reporter gene. Overall, his
results suggested that this peach type II
chlorophyll a/b binding protein gene is not
regulated by exogenous ethylene. However,
results from transient expression assays
demonstrate that
wound ethylene resulting from the bombardment procedure interferes with
expression when the CAB promoter is driving
gene expression. Jonathan presented
his work at the annual meeting of the
American Society of Plant Biologists,
Honolulu, HI. Jonathan received his Ph.D.
from the Plant Biology
Department at the University of California,
Davis and is a Postdoctoral scholar, Salk Institute, San Diego, CA.
Articles:
Gilkerson, J.G., J.A. Kelley, and M.A. Harrison. 2009. Evaluation of ethylene production in tobacco and
Arabidopsis induced by particle bombardment.
Presentations:
Gilkerson, J. and M. A. Harrison. 2003. Regulation of a Peach Type II Chlorophyll a/b-binding Protein Gene by
Exogenous Ethylene. Plant Biology 2003: 147. Poster at the American
Society of Plant Biologists meeting, Honolulu, HI.
