Malinna Jusoh
Universiti Malaysia Terengganu, Malaysia
Title: Effects of gibberellin on oil accumulation, fatty acid compositions and expression of fatty acid biosynthetic genes in Chlorella vulgaris (Trebouxiophyceae)
Biography
Biography: Malinna Jusoh
Abstract
Gibberellin (GA) is a plant hormone that regulates many physiological processes in plants. In microalgae, GA is synthesized through a slightly different pathway from higher plant GA. Recent studies have shown that several plant hormones such as auxin and jasmonic acid influence microalgae growth and fatty acid accumulation. In this study, the effects of exogenously applied GA were investigated on the growth and total oil content of a marine microalga, Chlorella vulgaris (Trebouxiophyceae) during early stationary growth phase. Results showed that GA gradually increases the cell density of C. vulgaris to up to 42% on days after treatment (DAT)-8 and also capable of delaying the algal senescence. However, the increment in cell density did not enhance the total oil production albeit transient modification of fatty acid compositions was observed for saturated (SFA) and polyunsaturated fatty acid (PUFA). This illustrates that GA only promotes cell division and growth but not the oil accumulation. In addition, application of GA in culture medium was shown to promote transient increment of palmitic (C16:0) and stearic (C18:0) acids from DAT-4 to DAT-6 and this changes is correlated with the expression of β-ketoacyl ACP synthase I (KAS I) gene. This result verified the function of this gene in the fatty acid biosynthesis pathway to produce C16:0 fatty acid.