Poster: Cell Walls

Abs # 1252: Differential expression screen for apple genes expressed at one month or five months of storage

Presenter:	Mann, Harpartap S, mann0188@umn.edu
Authors	Mann, Harpartap S (A)   Alton, Jennifer J (A)   Tong, Cindy B (A)
Affiliations:	(A): Department of Horticulture, University of Minnesota

Postharvest fruit softening is a unique biological phenomenon and is a major problem for the fruit industry. Tomatoes have been used as a model system to study fruit softening, but the texture of tomatoes is quite different from that of other fruits, such as apples. The typical softening profile for apples is nonlinear, which suggests that differential enzyme activity occurs at various stages in stored fruit. We used a PCR-based cDNA subtraction technique called suppression subtractive hybridization to enrich for cDNAs from fruit cortex tissue of the apple cultivar 'Macoun'. Fruit that had been stored for one month were compared to those stored for five months. Forty-seven putatively differentially-expressed cDNAs were identified. six of the clones had significant sequence similarity to genes for xyloglucan endo-transglycosylase, protein phosphatase 2C, 6-phosphoglucanolactanose, cysteine protease and a high molecular weight heat shock protein. Eleven clones did not match to any known gene sequence in the NCBI nucleotide database. Ten of the eleven 'unknowns' had a significant sequence similarity to entries from tomato, potato and peach fruit EST libraries. Differential expression of the clones of interest will be confirmed through RNA gel blots.