Protoplast isolation and regeneration from the potential economic brown alga Petalonia fascia (Ectocarpales, Phaeophyceae)

Petalonia fascia is a widespread brown alga with economic potential due to its use as raw or dried powder, and in the biomedical field. Protoplasts are living plant cells devoid of cell wall with a wide range of applications in basic and applied research, especially in crop improvement, and as a seedstock in seaweeds. Protoplasts have been previously isolated from P. fascia, but, their regeneration ability, an important prerequisite for protoplast applications, has not been explored. In this work, we report the protoplast isolation and successful regeneration from P. fascia using the commercially available cellulase “Onozuka” RS (1%) and alginate lyase (4 U mL−1). Protoplast production was enhanced under increased osmolarity (2512 mOsm L−1 H2O), with chelation pre-treatment, and short incubation time (4 h). Our protocol produced more than 14 times the number of protoplasts obtained using previously reported protocols. After 4 weeks in culture, protoplasts developed into prostrate and discoid and mixed thallus, as well as cell clumps. Blades mostly emerged from prostrate thalli. Antibiotics were not crucial for improving protoplast regeneration, and temperature did not affect the development of the morphological forms and blades. Our results show that high yields of protoplasts (107 protoplasts g−1 FW) with good regeneration ability can be obtained from P. fascia using a simple mixture of commercial enzymes. This represents the first report of successful protoplast regeneration in P. fascia.