Molecular cloning and sequencing of thioesterase B cDNA and hormonal induction of this thioesterase in the uropygial gland of mallard duck and molecular cloning of genes whose expression are triggered uniquely during appressorium formation in Colletotrichum gloeosporioides induced by its plant host signal.

摘要

The primary structure deduced from the cDNA of a medium-chain fatty acyl-CoA hydrolase designated thioesterase B from the uropygial gland of mallard duck was determined. Polymerase chain reaction (PCR) with two degenerate primers and the first strand of cDNA generated from the poly(A);Appressorium formation in germinating Colletotrichum gloeosporioides is induced by the surface wax of the host, the avocado fruit. From a cDNA library for the transcripts present in appressorium forming spores the clones representing nongerminating spores were removed by hybridization with the cDNA for the nongerminating spores. From this subtracted library, three clones were isolated and sequenced. Northern blot analysis showed that transcripts that hybridized with these three clones were expressed in the spore only during the appressorium formation induced by avocado surface wax. Nucleotide sequences of the clones revealed that one clone, CAP3, contained an open reading frame that would code for a 26-amino acid cysteine-rich peptide. Another clone, CAP22, contained an open reading frame that could code for a 227-a.a. polypeptide. The other clone, CAP20, contained an open reading frame that could encode a 183-a.a. polypeptide. Both polypeptides did not have significant homology to any known proteins.