Expression of a phenylcoumaran benzylic ether reductase-like protein in the ovules of Gossypium hirsutum

Two dimensional polyacrylamide gel electrophoresis (2D-PAGE) was used to identify differentially expressed proteins in wild-type (DP 5690) and fiberless (SL 1-7-1) cotton ovules. One protein, designated V2 was unique to ovules of the fiber producing DP 5690 line. The protein was purified from 2D-PAGE of 4 d post anthesis DP 5690 ovules and partially sequenced. The short amino acid sequence was nearly identical to the deduced amino acid sequence for cotton phenylcoumaran benzylic ether reductase (PCBER) protein. A consensus sequence was assembled from ESTs encoding cotton PCBER genes, primers were designed, and a full length gene was amplified from plasmid DNA from a 72 h etiolated cotton cotyledon library. The polymerase chain reaction generated a 950 bp product with unique EcoRI (5') and (3') KpnI restriction sites for directional insertion into the expression vector pPICZA. Nucleotide sequencing was performed, and the full length coding region was 924 bp encoding a protein of 308 amino acids. The molecular mass and pI measured (2D PAGE) were similar to the theoretical protein.