Involvement Of Rubisco In Astaxanthin Accumulation According To Photosynthetic Characters In Life Cycle Of Haematococcus Pluvialis

There is more and more concentration on astaxanthin by many researchers in the world, due to its effective coloration in aquaculture and anti-oxidation in nutracetical. Haematococcus is one of the most effective natural sources of astaxanthin.Cells of Haematococcus Pluvialis Flot. et Will in four different growth phases were collected, which are green vegetative cells, green unmoving cells, orange unmoving cells and red cysts. Ribulose-1,5-bisphosphate carboxylase (Rubisco) activity in crude extracts and large-subunit ribulose-1,5-bisphosphate caboxylase/oxygenase (rbcL) mRNA was quantified. Meanwhile, the ratios of photosynthesis rate to respiration rate (P/R), the maximal effective quantum yield of photosystem II (Fv/Fm), electron transport rate (ETR), actual photochemical efficiency of PSⅡin the light (ΦPSⅡ) and non-photochemical quenching (NPQ) were measured. Moreover, the content of astaxanthin was determined.It was showed that green vegetative cells were in the most active state with relatively higher P/R and they also displayed the lowest value of NPQ and the highest value of Fv / Fm, ETR andΦPSⅡ, indicating the most effective PSⅡ, but both Rubisco activity and rbcL mRNA expression were the lowest. However, in orange resting cysts with relatively lower P/R and NPQ, Rubisco activity and rbcL expression reached the peak, while Fv / Fm, ETR andΦPSⅡwas the lowest.Together with the methods of astaxanthin induction in industry, it was suggested that Rubisco possibly participated in astaxanthin accumulation rather than Calvin cycle in orange resting cells; therefore, some carbon source such as CO2 should be sufficiently supplied in a large scale of astaxanthin production in Haematococcus pluvialis.