Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 11/7/2003
Publication Date: 6/1/2004
Citation: Fish, W.W. 2004. The expression of polygalacturonase-inhibiting protein activity as a function of cantaloupe fruit maturation and fruit tissue origin [abstract]. Phytopathology. 94(6):S168.
Technical Abstract: Netted cantaloupe (Cucumis melo var. cantalupensis cv. Magnum 45) were harvested from five to thirty-five days postanthesis. The fruit of each age group were divided into exocarp, outer mesocarp, mid mesocarp, inner mesocarp, placenta, and seed tissues. Each tissue was extracted and assayed for polygalacturonase-inhibiting protein (PGIP) activity against polygalacturonases (PGs) from three fungal pathogens of cantaloupe fruit. The PGIP activity of all tissues except placenta was high from the flower stage through the first week of fruit development but decreased markedly between five and ten days postanthesis. PGIP activity in placental tissue against Phomopsis cucurbitae PG remained high and nearly constant throughout fruit development. However, PGIP activity in placental tissue versus Fusarium solani PG decreased during fruit development to about twenty-five percent of its original level in the five day-old fruit. This differential change in PGIP activity toward the two PGs suggests that different forms of the inhibitor are expressed between early and late stages of cantaloupe fruit development.