Confirmation of cultivated Porphyra tenera (Bangiales, Rhodophyta) by polymerase chain reaction restriction fragment length polymorphism analyses of the plastid and nuclear DNA.

Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis of the plastid ribulose-1,5-bisphosphate carboxylase (RuBisCo) spacer region was developed for a more reliable and rapid species identification of cultivated Porphyra in combination with PCR-RFLP analysis of the nuclear internal transcribed spacer (ITS) region. From the PCR-RFLP analyses of the plastid and nuclear DNA, we examined seven strains of conchocelis that were used for cultivation as Porphyra tenera Kjellman but without strict species identification. The PCR-RFLP analyses suggested that two strains, C-32 and 90-02, were cultivated P. tenera and that the other five strains, C-24, C-28, C-29, C-30 and M-1, were Porphyra yezoensis f. narawaensis Miura. To identify species more accurately and to reveal additional genetic variation, the two strains C-32 and 90-02 were further studied by sequencing their RuBisCo spacer and ITS-1 regions. Although RuBisCo spacer sequences of the two strains were identical to each other, each of their ITS-1 sequences showed a single substitution. The sequence data again confirmed that the two strains (C-32 and 90-02) were cultivated P. tenera, and suggested that the two strains showed some genetic variation. We concluded that PCR-RFLP analysis of the plastid and nuclear DNA is a powerful tool for reliable and rapid species identification of many strains of cultivated Porphyra in Japan and for the collection of genetically variable breeding material of Porphyra. [ABSTRACT FROM AUTHOR]