Cloning cDNAs for genes preferentially expressed during fruit growth in cucumber

A cDNA library was constructed from poly(A)(+)RNA extracted from pollinated fruit of 'PMR-142' cucumber (Cucumis sativus L.), Subtraction hybridizatio n was made between the cDNAs and poly(A)(+)RNA from unpollinated fruit to i solate cDNA clones that corresponded to the genes preferentially expressed in the pollinated fruit, We isolated three cDNAs, which were 756, 826, and 998 nucleotides long and designated Csf1, Csf2, and Csf3, respectively. Whe n fruit growth was triggered by pollination, auxin treatment and natural pa rthenocarpy, Csf2 was always expressed. Time course of expression of the Cs f2 gene was nearly parallel to that of the fruit growth. Nucleotide sequenc es of the Csf cDNAs were fully determined. Homology of the deduced amino ac id sequence for Csf1 showed 75 % identity with a pea extensin. Only 37%, 33 %, and 26% homology was found between Csf2 and hell pepper CaSn-2, tobacco FB7-4, and opium poppy gMLP15, respectively. The Csf3 sequence showed 68% i dentity with the large subunit of 60S ribosomal protein L3 of Arabidopsis t haliana.