Expression analysis of kenaf cinnamate 4-hydroxylase (C4H) ortholog during developmental and stress responses

This study was conducted to clone and analyze the expression pattern of a C4H gene encoding cinnamate 4-hydroxylase from kenaf (Hibiscus cannabinus L.). The full-length of the C4H ortholog was cloned using degenerate primers and the RACE (rapid amplification of cDNA ends) method. The full-length C4H ortholog contained a 1,518-bp open reading frame (ORF) encoding 505 amino acids. The deduced amino acid sequence showed that kenaf C4H had the highest similarity (95%) with that of Gossypium arboretum. We examined the expression patterns of the C4H ortholog in diverse tissues and at different developmental stages, as well as in response to abiotic stress conditions such as wounding, NaCl, cold, H2O2, ABA (abscisic acid) and SA (salicylic acid). Three-week-old stem tissues were used to examine the effects of abiotic stresses on C4H ortholog expression. While the highest transcript level of C4H ortholog was observed at an early stage in both stems and leaves, the transcripts were most abundant in the late stage flowers. In cases of wounding and SA, early induction of the C4H ortholog was observed. Conversely, H2O2 led to intermediate induction, while cold and ABA led to late induction. NaCl treatment showed different expression patterns such as complex biphasic expression. In summary, the C4H ortholog was expressed in all tissues and organs, as well as in response to various treatments.