Methyl jasmonate- or gibberellins A3-induced astaxanthin accumulation is associated with up-regulation of transcription of β-carotene ketolase genes (bkts) in microalga Haematococcus pluvialis

The microalga Haematococcus pluvialis accumulates astaxanthin in response to abiotic stresses. Since methyl jasmonate (MJ) and gibberellins A3 (GA3) are involved in the stress responses of plants, the impact of these compounds on astaxanthin metabolism was studied. Alga cells treated separately with MJ and GA3 accumulated more astaxanthin than the controls. MJ and GA3 treatment increased the transcription of three β-carotene ketolase genes (bkts). MJ- and GA3-responsive cis-acting elements were identified in the 5′-flanking regions of bkt genes. These results suggest that MJ and GA3 constitute molecular signals in the network of astaxanthin accumulation. Induction of astaxanthin accumulation by MJ or GA3 without any other stimuli presents an attractive application potential.