Molecular identification of the algal pathogen Pythium chondricola (Oomycetes) from Pyropia yezoensis (Rhodophyta) using ITS and cox1 markers

doi:2015.30.3.217

Algae > Volume 30(3); 2015 > Article

Algae 2015;30(3): 217-222. doi: https://doi.org/10.4490/algae.2015.30.3.217

Soon Jeong Lee¹, Mi Sook Hwang², Myoung Ae Park³, Jae Min Baek⁴, Dong-Soo Ha¹, Jee Eun Lee⁵ and Sang-Rae Lee⁶^,*

¹Seaweed Research Center, National Fisheries Research and Development Institute, Mokpo 530-831, Korea
²Aquatic Plant Variety Center, National Fisheries Research and Development Institute, Mokpo 530-831, Korea
³Aquatic Life Disease Control Division, National Fisheries Research and Development Institute, Busan 619-902, Korea
⁴West Sea Fisheries Research Institute, National Fisheries Research and Development Institute, Incheon 400-420, Korea
⁵Department of Earth Environmental System Oceanography Major, Pusan National University, Busan 609-735, Korea
⁶Marine Research Institute, Pusan National University, Busan 609-735, Korea

*Corresponding Author

Email: sangraelee@pusan.ac.kr

ABSTRACT

Pythium species (Pythiales, Oomycetes) are well known as the algal pathogen that causes red rot disease in Pyropia / Porphyra species (Bangiales, Rhodophyta). Accurate species identification of the pathogen is important to finding a scientific solution for the disease and to clarify the host-parasite relationship. In Korea, only Pythium porphyrae has been reported from Pyropia species, with identifications based on culture and genetic analysis of the nuclear internal transcribed spacer (ITS) region. Recent fungal DNA barcoding studies have shown the low taxonomic resolution of the ITS region and suggested the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene as an alternative molecular marker to identify Pythium species. In this study, we applied an analysis of both the ITS and cox1 regions to clarify the taxonomic relationships of Korean Pythium species. From the results, the two closely related Pythium species (P. chondricola and P. porphyrae) showed the same ITS sequence, while the cox1 marker successfully discriminated P. chondricola from P. porphyrae. This is the first report of the presence of P. chondricola from the infected blade of Pyropia yezoensis in Asia. This finding of the algal pathogen provides important information for identifying and determining the distribution of Pythium species. Further studies are also needed to confirm whether P. chondricola and P. porphyrae are coexisting as algal pathogens of Pyropia species in Korea.

Key words: cox1; ITS region; Pyropia yezoensis; Pythium chondricola; Pythium porphyrae; red rot disease