Diversity, phenomenology and epidemiology of epiphytism in farmed<i>Gracilaria chilensis</i>(Rhodophyta) in northern Chile

Leonardi, Patricia I.; Miravalles, Alicia B.; Faugeron, Sylvain; Flores, Verónica; Beltrán, Jessica; Correa, Juan A.

doi:10.1080/09670260600645659

Cited by 76 publications

(70 citation statements)

References 48 publications

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“…2l, o). This invasion type is consistent with that of an epitrophic fungus (Leonardi et al 2006;Linskens 1976). By 11 dpi, a hyphal network substantially covered and grown within the inoculated roots (Fig.…”

supporting

confidence: 60%

Intercellular invasion of rice roots at the seedling stage by the rice false smut pathogen, Villosiclava virens

Prakobsub

Ashizawa

2017

J Gen Plant Pathol

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) have been explored, little information is available detailing the initial infection process. To clarify the initial infection process of V. virens into rice roots at the seedling stage, we inoculated seedlings with axenically cultured chlamydospores of V. virens and followed germination and the route of invasion.Seedlings of rice (Oryza sativa) variety Yumeaoba, which is susceptible to rice false smut disease, was used for inoculation. The seeds were soaked in a 0.5% (v/v) solution of the fungicide Techleed C Flowable (ipconazole and copper; Kumiai Chemical Industry, Tokyo, Japan) at 26 °C for 24 h, and then kept in distilled water (DW) for 3 days at 26 °C. Germinated seeds were selected and soaked in 70% (v/v) ethanol for 5 min and rinsed twice in DW. The germinated seeds were cultured on Murashige and Skoog (MS) medium in plastic plates (97 × 140 mm) at 25 °C under a 12 h/12 h (light/dark) cycle for 7 days. Seedlings were selected and carefully removed from the agar, washed in DW, and then kept in a petri dish (9-cm diameter) until inoculation.Dried barley seeds containing isolate U2003-1 of V. virens (Ashizawa et al. 2010) were cultured on brown rice medium (100 g brown rice and 100 mL DW) at 25 °C. At 1 month post-incubation (mpi), a mass of chlamydospores formed on the medium, which was covered with velvety yellow hyphae; the surface of the chlamydospore mass was gradually cracking open (Fig. 1). The chlamydospores slowly changed from yellow to deep orange until 5 mpi. In a preliminary inoculation test, chlamydospores at 1 to 4 mpi did not germinate on inoculated rice roots, and no infection hyphae were observed. For this reason, actively growing chlamydospores at 5 mpi were used for further study. For inoculum, 5-mpi chlamydospores were gently suspended in DW filtered through tissue paper and adjusted to 1 × 10 5 chlamydospores/mL. In addition, by transferring Abstract False smut is a serious disease affecting rice production worldwide. Initial infection of rice seedlings by Villosiclava virens was clarified using axenically cultured chlamydospores to inoculate rice roots. Chlamydospores were found on rice roots at 1 day post inoculation (dpi), and were germinating at 1-4 dpi. At 4 dpi, the infection germ tube had invaded the intercellular space between epidermal rice root cells. Between 5 and 11 dpi, branching and fusion-like structures were observed that may contribute to the establishment of the hyphal network on the root surface. Keywords

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supporting

confidence: 60%

Intercellular invasion of rice roots at the seedling stage by the rice false smut pathogen, Villosiclava virens

Prakobsub

Ashizawa

2017

J Gen Plant Pathol

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“…For example, studies of Gracilaria sp. farming in Chile, which mainly focused on epiphytes (Buschmann & Gómez 1993, Fletcher 1995, Leonardi et al 2006) and kelp farming in Asia, with a focus on fouling hydroids and copepods (Park et al 1990, Park & Hwang 2012. However, due to the slower growth of the cultivation industry in Europe, research on associated epibionts has only begun more recently (Peteiro & Freire 2013b, Førde et al 2016, Walls et al 2016.…”

Section: Introductionmentioning

confidence: 99%

Successional changes of epibiont fouling communities of the cultivated kelp Alaria esculenta: predictability and influences

Walls¹,

Edwards²,

Firth³

et al. 2017

Aquacult. Environ. Interact.

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There has been an increase in commercial-scale kelp cultivation in Europe, with fouling of cultivated kelp fronds presenting a major challenge to the growth and development of the industry. The presence of epibionts decreases productivity and impacts the commercial value of the crop. Several abiotic and biotic factors may influence the occurrence and degree of fouling of wild and cultivated fronds. Using a commercial kelp farm on the SW coast of Ireland, we studied the development of fouling communities on cultivated Alaria esculenta fronds over 2 typical growing seasons. The predictability of community development was assessed by comparing mean occurrence-day. Hypotheses that depth, kelp biomass, position within the farm and the hydrodynamic environment affect the fouling communities were tested using species richness and community composition. Artificial kelp mimics were used to test whether local frond density could affect the fouling communities. Species richness increased over time during both years, and species composition was consistent over years with early successional communities converging into later communities (no significant differences between June 2014 and June 2015 communities, ANOSIM; R = −0.184, p > 0.05). The timing of species occurrences was predictable across years for all shared species. Variations in biomass, depth and position within the farm had no significant effect on species richness and composition. Results from artificial kelp mimics suggest possible hydrodynamic effects. The ability to understand succession and the timing of occurrences of fouling organisms and predict their arrival has significant benefits for the seaweed cultivation industry.

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“…Analyzing the thallus cross-sections of H. musciformis, it was observed that the epiphytic species of diatoms were weakly attached to the surface without damaging the thallus. Thus, this infection was characterized as type I (Leonardi et al, 2006) (Figure 1). However, S. subintegra was strongly adhered to the surface of H. musciformis thallus, but without invading the cortical cells, characterizing an infection of type II (Leonardi et al, 2006) (Figure 1) During the incubation time, the brown morpho of H. musciformis showed little infection by diatoms and rare red crusts of Sahlingia subintegra.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, this infection was characterized as type I (Leonardi et al, 2006) (Figure 1). However, S. subintegra was strongly adhered to the surface of H. musciformis thallus, but without invading the cortical cells, characterizing an infection of type II (Leonardi et al, 2006) (Figure 1) During the incubation time, the brown morpho of H. musciformis showed little infection by diatoms and rare red crusts of Sahlingia subintegra. In comparison, the green morpho had diatoms in larger quantities and numerous red crusts (S. subintegra), mainly in the basal portion of the explants.…”

Section: Resultsmentioning

confidence: 99%

Protocol for seaweed decontamination to isolate unialgal cultures

Fernandes¹,

Yokoya²,

Yoneshigue‐Valentin³

2011

Rev. bras. farmacogn.

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Decontamination protocols in seaweeds are essential tools for ecophysiological studies in laboratory cultures. These protocols consist of a set of procedures and physical and chemical treatments that must be adjusted for each species. Thus, the effects of explant size and of combinations of physical treatments (brushing and cutting) and chemical treatments (sodium hypochlorite, detergent, seawater, distilled water, germanium dioxide) on the process of obtaining unialgal culture of two pigmentar morphos of Hypnea musciformis were investigated. It was found that thallus segments 50 mm in length, when transported from the field to the laboratory, remained healthier and were less susceptible to epiphytes than those 7 mm in length. The collected material had surfaces contaminated by diatoms, which were weakly attached, as well as surface contamination caused by strongly attached Sahlingia subintegra. The most efficient combination of physical and chemical treatments was explant brushing, cutting and washing with detergent. This combination eliminated the contamination by S. subintegra, but not all of the diatom contamination. The population of the latter was reduced by using physical treatment and by washing with detergent and distilled water and then exterminated by using germanium dioxide (0.003 mg/L). Employing this protocol, unialgal cultures of H. musciformis could be established in approximately eight to ten weeks.

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Diversity, phenomenology and epidemiology of epiphytism in farmedGracilaria chilensis(Rhodophyta) in northern Chile

Cited by 76 publications

References 48 publications

Intercellular invasion of rice roots at the seedling stage by the rice false smut pathogen, Villosiclava virens

Intercellular invasion of rice roots at the seedling stage by the rice false smut pathogen, Villosiclava virens

Successional changes of epibiont fouling communities of the cultivated kelp Alaria esculenta: predictability and influences

Protocol for seaweed decontamination to isolate unialgal cultures

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