Jonggeun Kim, Bosung Choi, Byoung-Kwan Cho, Hyoun-Sub Lim, Joon Bum Kim, Savithiry Natarajan, Eunjung Kwak, Hanhong Bae
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. 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 (SA), NaCl, cold, H2O2 and methyl jasmonate (MeJA)]. 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. Threeweek-old stem tissues were used to analyze COMT ortholog expression upon abiotic stresses. The highest level of COMT transcript (32%, relative to ACTIN) 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.
Keywords: kenaf (Hibiscus cannabinus), phenylpropanoid pathway, COMT (caffeic acid O-methyltransferase), lignification, abiotic stresses.
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