CDNA cloning of chloroplast omega-3 fatty acid desaturase from Capsicum annuum and its expression upon wounding.
A clone for a plastid omega-3 fatty acid desaturase (FAD) was isolated from a leaf cDNA library of hot pepper (Capsicum annuum L.). The nucleotide sequence of a 1,317 bp open reading frame in the CachFAD showed 80.9% homology with that of tobacco plant. It codes for a polypeptide of 438 amino acids with molecular mass of 50.5 kDa and a pI of 8.14. The CachFAD had a putative transit peptide for targeting the chloroplast. Genomic Southern hybridization indicated that it exists as small gene family. Northern hybridization revealed that its mRNA was present in leaves, but not in roots. Transcript levels in the leaves upon wounding increased rapidly to reach the first peak between 1-3 h, decreased thereafter and slightly increased at 24 h after wounding. The levels of linolenic acid (18:3) in wounded leaves also reached the first peak at 6 h, decreased thereafter and reached the second peak at 18 h. These results indicated that wounding not only enhanced the accumulation of the CachFAD mRNA but also increased the conversion of linoleic acid (18:2) to linolenic acid (18:3) in leaf lipids of hot pepper.
Kwon
J H
JH
School of Biological Sciences, Seoul National University, Korea.
Lee
Y M
YM
An
C S
CS
D000595:Amino Acid Sequence; D001483:Base Sequence; D002212:Capsicum / Q000201:enzymology / Q000254:growth & development / Q000502:physiology*; D002736:Chloroplasts / Q000201:enzymology*; D003001:Cloning, Molecular; D018076:DNA, Complementary; D044943:Fatty Acid Desaturases / Q000235:genetics* / Q000378:metabolism*; D005227:Fatty Acids / Q000032:analysis; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D018515:Plant Leaves / Q000737:chemistry / Q000201:enzymology; D010946:Plants, Medicinal; D016133:Polymerase Chain Reaction; D015183:Restriction Mapping
D018076:DNA, Complementary; D005227:Fatty Acids; D044943:Fatty Acid Desaturases; C078565:omega-3 fatty acid desaturase