Isolation and characterization of a heat-resistant strain with high yield of Pyropia haitanensis induced by ultraviolet ray

Abstract The blades of the wild-type strain (WT-10) of Pyropia haitanensis were irradiated with ultraviolet ray and treated with heat stress, and then a heat-resistant strain (SW-81) with high yield was isolated. Ultraviolet ray has a good effect on mutagenesis of tender blades of P. haitanensis, when the irradiation dose increased from 0 to 600 μW•min/cm2, the frequency of the color-mutated cell-clusters was higher with increased of the dose, however, further increase of the dose up to 800 μW•min/cm2, decreased the the frequency of the color-mutated cell-clusters, indicating that 600 μW•min/cm2 was the suitable mutagenesis dose. Evaluation of genetic variations of the blades of SW-81 was performed using sequence-related amplified polymorphism (SRAP) analysis, indicating that the SW-81 strain was obtained by mutagenesis. The WT-10 strain and new cultivar (SF-2) of P. haitanensis were used as the control group to analyze the characteristics of SW-81 strain. The growth rate and quality of the blades of SW-81 strain were similar to those of SF-2, and much higher than those of WT-10 strain. The heat resistance of the blades of SW-81 strain was better than that of WT-10 and SF-2. The differentiation rate of conchocelis inoculated shell in SW-81 strain was similar to that in WT-10 strain, and faster than that in SF-2. These results indicate that SW-81 strain can replace SF-2 for cultivation in the aquaculture areas.