Our lab is addressing the biochemistry and molecular biology of fruit ripening
and senescence with the goal of understanding
the factors that contribute to the deterioration and loss of quality in harvested horticultural commodities. Included are mechanisms of programmed cell death, both senescence and apoptosis, and how these are influenced by commodity type and maturity at harvest.
Current objectives are directed toward understanding the mechanism of watersoaking and associated membrane and cell wall catabolism, in situ factors
that restrict the activities of wall-localized enzymes, and the synergy between
cell wall metabolism and membrane deterioration in response to mechanical and
chilling stress. We are also interested in the effects of ethylene antagonists,
particularly 1-methylcyclopropene, on fruit ripening and senescence, apoptosis, and the differential recovery of ripening parameters in 1-MCP-treated fruits.
Additional interests related to ethylene antagonists include their possible
benefits with use with fresh-cut commodities.
Influence of 1-methylcylclopropene on quality maintenance of 'Galia' melons.
Fruit were treated with 1-MCP at concentrations of 1 ppm, 100 ppb, 10 ppb and 0 ppb (control). Cross-sectional images of fruit stored for 5 days are shown. Note that the control fruit and fruit treated with low levels of 1-MCP exhibit clear signs of over-ripening (watersoaking) whereas the fruit treated with 1-MCP at 1 ppm remain structurally sound with no evidence of internal deterioration.
Watersoaking of watermelon fruit exposed to ethylene and the prophylatic effect of 1-methylcyclopropene (1-MCP) on this response.
Pictured, left to right, are representative fruits following 8 days storage in air, 1-MCP alone, 1-MCP + ethylene, and ethylene alone. The more intense red coloration of the ethylene-treated fruit reflects acute watersoaking and tissue maceration. We are currently studying the role of membrane and cell wall hydrolysis in this disorder
mRNA differential display analysis of gene expression in fresh cut and intact papaya fruit.
Click the image to get a larger picture.
Fresh cut and intact papaya fruit were stored at 5 ° C for 12h, and the total RNA extracted from each sample was reverse transcribed and then amplified using three different oligo dT primers and 8 different arbitrary primers. From left to right, lanes adjacent to each other show intact and fresh fruit respectively.
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