Jong-il Choi
Department of Biotechnology and Bioengineering, Chonnam National University, Gwangju 61186, Republic of Korea
A mutant Pyropia tenera with improved tolerance to high temperatures was obtained using gamma irradiation. There was selected a mutant Pt1k with improved heat tolerance and different blade colour at high temperatures (20 °C) after an irradiation dose of 1 kGy. The selected Pt1k mutant blades were dark green, which was different from the natural red of the WT. At 12 °C, Pt1k blade growth rate and biomass were four times higher than those of the WT, and phycocyanin (PC) content also increased. When cultured at 20 and 25 °C, blade shapes and growth rates of Pt1k were maintained; however, WT blades were considerably decayed and growth rate was inhibited. When cultured at 25 °C for 3 weeks, chlorophyll a and PC contents were higher in Pt1k than in WT strains, whereas the phycoerythrin (PE) level was constant. These results indicate that the isolated mutant Pt1k had improved growth and tolerance to higher temperatures than the WT.