Characterization of high temperature-tolerant strains of Pyropia yezoensis

Abstract

High-temperature stress related to global warming reduces the growth and productivity of seaweeds. Thus, the development of new strains is urgently required for maintaining or even enhancing the productivity of useful seaweeds such as red alga Pyropia yezoenesis in an increasingly warmer sea environment. To develop competitive high-temperature-tolerant strains of P. yezoensis (Sugwawon no. 104), we screened libraries of gamma-irradiated strains and identified high-temperature-resistant (HTR) mutants. Our results showed that HTR-1 and HTR-2 grew well at higher temperatures that inhibited the growth of the wild-type strain. The efficiency of conchosporangium maturation and conchospore release of HTR-1 was similar to or higher than the wild-type strain. Moreover, thallus growth, pigment content, photosynthetic efficiency, and monospore release from the growing thallus in HTR-1 could be maintained even at high temperature. Taken together, our data demonstrate that HTR-1 may be suitable for industrial cultivation at sea, even at elevated temperatures.