|Natarajan, Savithiry - Savi|
Submitted to: Plant Omics
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/15/2013
Publication Date: 7/20/2013
Citation: Kim, J., Cho, B., Lim, H., Natarajan, S.S., Bae, H. 2013. Molecular cloning, characterization and expression of the caffeic acid O-methyltransferase (COMT) ortholog from kenaf (Hibiscus cannabinus). Plant Omics. 6(4):246-253. Interpretive Summary: Kenaf (Hisbiscus cannabinus) is an annual fast growing plant and is used for making rope, cordage, canvas, sacking, carpet backing, nets, table cloths, etc. Recently, it has gained more attention as a possible source for the production of biomass fuels. For producing biofuels from plants, major technical problems occur in biological conversion due to higher interactions between lignin and polysaccharides. To address this problem, the study of the regulation of genes involved in the metabolic pathways leading to lignin production is important. We examined the changes in gene activity associated with one of the pathway genes called “caffeic acid O-methyltransferase (COMT)” during different developmental stages of the Kenaf plant as well as with different stress applications. We found that the COMT gene was expressed in all tissues, as well as in response to various stress treatments. This information will be useful to scientists to select suitable plant genotypes for biomass production.
Technical Abstract: We cloned the full-length of the gene putatively encoding caffeic acid O-methyltransferase (COMT) from kenaf (Hibiscus cannabinus L.) using degenerate primers and the RACE (rapid amplification of cDNA ends) method. Kenaf is an herbaceous and rapidly growing dicotyledonous plant with great potential for biomass production. COMT is an important methylating enzyme in the phenylpropanoid pathway that belongs to the SAM (S-adenosyl L-methionine)-dependent methyltransferases family. We investigated the expression pattern of kenaf COMT during developmental stages in different tissues and organs as well as in response to diverse abiotic stresses (wounding, salicylic acid, NaCl, cold, H2O2 and methyl jasmonate). The full-length COMT ortholog is composed of a 1,098-bp open reading frame (ORF) encoding 365 amino acids. The deduced amino acid sequence indicated that kenaf COMT had the highest similarity (95%) with that of Gossypium hirsutum. Three-week-old stem tissues were used to analyze COMT ortholog expression upon abiotic stresses. The highest level of COMT transcript was detected at an early stage (4-week old) during stem development. The transcript levels of COMT ortholog were almost constant during the developmental stages of leaves and flowers, while early induction of the COMT ortholog was detected following wounding, SA, cold and H2O2 treatments, and MeJA led late induction and NaCl led to intermediate induction of the COMT ortholog.