Infection and cox2 sequence of Pythium chondricola (Oomycetes) causing red rot disease in Pyropia yezoensis (Rhodophyta) in Korea

Abstract

Geographic distributions of pathogens are affected by dynamic processes involving host susceptibility, availability and abundance. An oomycete, Pythium porphyrae, is the causative agent of red rot disease, which plagues Pyropia farms in Korea and Japan almost every year and causes serious economic damage. We isolated an oomycete pathogen infecting Pyropia plicata from a natural population in Wellington, New Zealand. The pathogen was identified as Pythium porphyrae using cytochrome oxidase subunit 1 and internal transcribed spacer of the rDNA cistron molecular markers. Susceptibility test showed that this Pythium from New Zealand was able to infect several different species and genera of Bangiales including Pyropia but is not able to infect their sporophytic (conchocelis) phases. The sequences of the isolated New Zealand strain were also identical to Pythium chondricola from Korea and the type strain from the Netherlands. Genetic species delimitation analyses found no support for separating P. porphyrae from P. chondricola, nor do we find morphological characters to distinguish them. We propose that Pythium chondricola be placed in synonymy with P. porphyrae. It appears that the pathogen of Pyropia, both in aquaculture in the northern hemisphere and in natural populations in the southern hemisphere is one species.Key Words: Bangia; Bangiales; DNA barcoding; host specificity; Porphyra; Pythium chondricola; Rhodophyta; species delimitation; synonymization; taxonomy INTRODUCTIONAquaculture of marine algae is an important industry, especially in Asia. The production of seaweeds more than doubled between 2000 and 2012 (Food and Agriculture Organization of the United Nations 2014). The red alga Pyropia is the most consumed alga in the world, both for food and in the biomedical industry (e.g., porphyran, pycobilliproteins) (Gachon et al. 2010). In 2013, Pyropia made up about 1.8 million tons which is about 8% of the total global seaweed production, with values of US $1.2 billion (FAO FishStat et al. 2016).Pyropia cultivation losses amount to over US $10 million annually from different diseases (Gachon et al. 2010, Blouin et al. 2011, Kim et al. 2014. Diseases like greenspot disease and Olpidiopsis blight as well as red-rot disease, result in a great decrease in productivity, yield and crop value (Kawamura et al. 2005, Klochkova et al. 2012, 2016b, Kim et al. 2014. With increasing farming intensity and increasing temperatures, caused by global warming, disease severity and occurrence is also expected to increase (Ding and Ma 2005, Gachon et al. 2010).Received January 17, 2017, Accepted February 25, 2017 *Corresponding Author E-mail: joe.zuccarello@vuw.ac.nz Tel: This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 30 well investigated in aquacultural settings (e.g., Park ...

Compositional Shifts of Bacterial Communities Associated With Pyropia yezoensis and Surrounding Seawater Co-occurring With Red Rot Disease

“…Economic incentives have driven intensive cultivation practices, and the increasing scale of production has caused a nutrient deficiency in the cultivate area, which affects the normal growth of Pyropia (Huang et al, 2000). Pyropia species have subsequently been rendered susceptible to several diseases, including red rot disease (Arasaki, 1947; Takahashi, 1977; Ding and Ma, 2005; Lee et al, 2017), Olpidiopsis disease (Arasaki, 1960; Ding and Ma, 2005; Kwak et al, 2017), and green spot disease (Fujita, 1990; Kim et al, 2016) in the blade stage, in addition to yellow spot disease (Guan et al, 2017) and white spot disease (Guan et al, 2013) in the shell-boring conchocelis stage. These diseases have caused a significant decline in Pyropia production in recent years, leading to heavy economic losses (Kim et al, 2014).…”

The gene repertoire of <italic>Pythium porphyrae</italic> (Oomycota) suggests an adapted plant pathogen tackling red algae

“…Both are most likely conspecific as P. chondricola has been mostly observed parasitizing Pyropia sp. (Lee et al 2017, Qiu et al 2019 and most classical molecular markers used to reconstruct oomycete phylogenies are strictly identical to P. porphyrae (Lee et al 2015). Additional members of the same clade A include the soil-borne plant pathogen Pythium aphanidermatum (Lévesque and de Cock 2004) and pathogens occasionally reported on algal hosts (e.g., P. adhaerens) (Sparrow 1931).…”

The Taxonomy and Biology of Phytophthora and Pythium

“…50,51 and an unidentified species of Pythium isolated from a colony of diseased leafy liverworts from Signy Island of Antarctic proved to be a potential plant pathogen to local vascular plants, based on artificial inoculation. 52 Other species caused diseases in fish, 53 marine red algae 54,55 and mammals including humans, causing pythiosis. 56,57 On the other hand, some species of Pythium can produce valuable compounds for pharmaceutical and food industry, like polyunsaturated fatty acids, arachidonic acid and cicospentaenoic acid, 58 synthesize biotin, folic acid, pantothenic acid, riboflavin, thiamine and vitamin C, etc.…”