|Chowdhury, Emran Khan|
|Kim, Joon Bum|
|Natarajan, Savithiry - Savi|
Submitted to: Plant Omics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/2012
Publication Date: 7/1/2013
Citation: Chowdhury, E., Cho, B., Lim, H., Kim, J., Bae, H., Natarajan, S.S. 2013. Regulation of 4CL, encoding 4-coumarate: coenzyme A ligase, expression in kenaf under diverse stress conditions. Plant Omics. 6(4):254-262. 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 “4-coumarate: coenzymeA ligase (4CL)” during different developmental stages of the Kenaf plant. We found that the 4CL gene was expressed more in stem and root tissues and had lower expression in leaf and mature flower tissues. This information will be useful for scientists to select suitable plant genotypes for biomass production.
Technical Abstract: We cloned the full length 4CL ortholog encoding 4-coumarate: coenzymeA ligase from kenaf (Hibiscus cannabiuns) using degenerate primers and RACE (rapid amplification of cDNA ends) systems. The 4CL is a key regulatory enzyme of the phenylpropanoid pathway that regulates the activation of cinnamic acid, leading to the synthesis of flavonoids and lignin. The 1,704-bp full length of the 4CL ortholog had a 1,623-bp open reading frame (ORF) encoding a predicted protein of 540 amino acids. The predicted molecular weight and isoelectric point (pI) of the deduced protein was 59.56 kDa and 6.58, respectively. The sequence of the deduced amino acid shared 57-79% identity with other 4CL sequences. The 4CL ortholog had two conserved putative AMP (adenosine monophosphate)-binding motifs, the SSGTTGLPKGV and GEICIRG domains. A BlastP search showed that kenaf the 4CL ortholog showed 79% identity with ri4CL2 of Rubus idaeus (AAF91309), which is a class I 4CL involved in lignin synthesis. The 4CL ortholog showed differential expression in all tissues during the developmental stages and was highly expressed in stem and root tissues. However, the lowest expression of the 4CL ortholog was observed in leaf and mature flower tissues. The 4CL ortholog was responsive to various stress conditions in 3-week-old kenaf stem tissues. Wounding caused biphasic expression at 6h and 24h after treatment. Taken together, the results of this study contribute to the knowledge of the presence of the 4CL ortholog and its possible role in lignin biosynthesis, as well as its differential expression during developmental stages.