Carotenogenesis in Haematococcus pluvialis cells under the combined action of excess of NaCl in the culture medium and high light intensity

The parameters of growth and development of the microalga Haematococcus pluvialis, as well as the process of carotenogenesis, including the pigment composition and expression of the key genes of astaxanthin biosynthesis, were studied in algal cells under the combined action of excess of NaCl in the culture medium and high light intensity. It was found that the combination of excess of NaCl in the culture medium for Haematococcus pluvialis, initiated at the resting stage of the microalga, and high light intensity is not an effective method for induction of the accumulation of astaxanthin in the cells of Haematococcus pluvialis. A decrease in the level of expression of one of the key genes of carotenogenesis - phytoene synthase gene, was revealed under such conditions. At the same time, it was found that the combined action of high light intensity and excess of NaCl led to an increase in the ratio of astaxanthin cis-isomers, which are more biotechnologically valuable, in the total pigment pool.