Cloning and expression of desoxyhemigossypol-6-O-methyltransferase from cotton (Gossypium barbadense).
Terpenoids play an important role in defense against insects and pathogens in cotton. These terpenoids contain phenolic groups. Metabolites in which the phenolic group has been converted to a methoxy group are less toxic to most insects and pathogens and thus may alter resistance. Here is reported the cloning of a gene from Gossypium barbadense that encodes the enzyme that methylates the phenolic group of desoxyhemigossypol (dHG) exclusively at the 6-position, dHG-6-O-methyltransferase (dHG-6-OMT). Partial peptide sequences from digests of purified dHG-6-OMT were used to design primers for RT-PCR amplification of cDNA fragments from poly(A) mRNA. Fragments were extended to full length using 5' and 3' RACE. The resulting cDNA codes for a 365-residue polypeptide with a calculated molecular weight of 40.6 kDa, in agreement with the molecular mass of purified dHG-6-OMT. When expressed in Escherichia coli, the bacterial lysates showed a high specificity for the methylation of desoxyhemigossypol, differentiating the cloned gene from other pathogen-induced methyltransferases.
Liu
Jinggao
J
Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, USA.
Benedict
Chauncey R
CR
Stipanovic
Robert D
RD
Magill
Clint W
CW
Bell
Alois A
AA
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D017124:Conserved Sequence; D018076:DNA, Complementary / Q000737:chemistry; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D003368:Gossypium / Q000201:enzymology* / Q000235:genetics*; D008745:Methylation; D008780:Methyltransferases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010572:Pest Control, Biological; D010802:Phylogeny; D010935:Plant Diseases; D011994:Recombinant Proteins; D013379:Substrate Specificity; D013729:Terpenes / Q000378:metabolism
D018076:DNA, Complementary; D011994:Recombinant Proteins; D013729:Terpenes; D008780:Methyltransferases; C459095:desoxyhemigossyol-6-O-methyltransferase