Molecular cloning and characterization of rosmarinic acid biosynthetic genes and rosmarinic acid accumulation in Ocimum basilicum L.

We have aimed to investigate the expression of genes related to rosmarinic acid (RA) synthesis and rosmarinic acid content in 2 Ocimum basilicum cultivars, green (cinnamon) and purple (red rubin) basil. Specifically, genes related to rosmarinic acid biosynthesis were cloned and characterized for O. basilicum. We obtained partial cDNAs of tyrosine aminotransferase (TAT) and 4-hydroxyphenylpyruvate reductase (HPPR), which were of 323 bp and 616 bp in size, respectively. The transcription levels of most genes related to rosmarinic acid synthesis were higher in green basil compared to purple basil, except for ObPAL and Ob4CL in the root. The highest expression was obtained in the leaves of green basil for all genes and the roots of purple basil for all genes, except for TAT. The highest rosmarinic acid content was obtained in the leaves of both cultivars, with higher RA accumulating in green basil compared to purple basil. The leaves had the highest RA content out of all plant organs, with the RA accumulation in the leaves of green basil being 1.64 times higher compared to purple basil. Further study is required to investigate whether a similar trend is observed across O. basilicum cultivars of different color types.