Browsing by Author "Camus, Carolina"

Now showing 1 - 5 of 5
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    Assessment of genetic and phenotypic diversity of the giant kelp, Macrocystis pyrifera, to support breeding programs
    (2018) Camus, Carolina; Faugeron, Sylvain Wielfrid; Buschmann, Alejandro H.
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    Assessment of local adaptation and outbreeding risks in contrasting thermal environments of the giant kelp, Macrocystis pyrifera
    (2024) Solas, Maribel; Correa, Rodolfo A.; Barria, Fernanda; Garces, Cristobal; Camus, Carolina; Faugeron, Sylvain
    Understanding the scope of local adaptation is critical to the definition of restoration strategies as it may affect individuals used as breeders or transplants. The assessment of such risks is, however, challenging for large seaweeds such as kelps, because their experimental manipulation is difficult in marine coastal environments. We investigated the consequences of local adaptation on reproductive traits of gametophytes, and growth and survival of sporophytes of the giant kelp, Macrocystis pyrifera. Over a thousand juvenile sporophytes were obtained from controlled crosses using 2 to 3 parental sporophytes from each of 18 populations from 5 different regions (i.e. Magellanes. Southern Chile, Atacama, Peru and California), to assess fertility and fecundity of female gametophytes when exposed to males of different habitats, and to produce juvenile sporophytes that were used to test for local adaptation sensu stricto in common garden experiments. By comparing sympatric and allopatric combinations of source populations and the average temperature of the sampled regions, we detected a significant pattern of local adaptation. We quantified the risks associated with different combinations of population/habitat for the performance of juvenile sporophytes typically used as transplants in kelp restoration actions. We found evidence of reduced reproductive success associated with outbreeding for high latitude populations, while low latitude populations favored hybrid crosses, suggesting a shift between outbreeding depression and hybrid vigor across different habitats (i.e., temperature). We also showed that a heatwave equally increased mortality of sporophytes across all regions except for Peruvian inbred crosses, suggesting these low latitude populations hold key genetic resources for future actions under ocean warming. Altogether, these experiments provide a framework for assessing risks associated with the choice of source populations in any kelp species.
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    Contrasting response of Gracilaria chilensis (Gracilariales, Rhodophyta) life cycle stages to epiphyte infection
    (2023) Usandizaga, Sara; Beltran, Jessica; Faugeron, Sylvain; Camus, Carolina
    The red seaweed Gracilaria chilensis, a species extensively cultivated in Chile for agar extraction, was subjected to a bioassay to determine the susceptibility of tetrasporophytes, female and male gametophytes collected from natural and cultivated populations, to the red epiphyte Acrochaetium sp. and the brown epiphyte Ectocarpus sp. The settlement, attachment and germination of epiphytic algal spores on G. chilensis thalli were evaluated, and the photosynthetic responses and the concentration of total phenolic compounds were determined as a possible response of G. chilensis to biotic stress. The results showed that when the thalli were exposed to Acrochaetium infection, female individuals had a significantly lower percentage of germinated spores than other phases of the life cycle. After infection with Ectocarpus spores, males showed the highest % germination of the epiphyte. For both epiphytes, the response of tetrasporophytes from natural and cultivated populations shows a similar trend. The total content of phenolic compounds showed that, in general, the individuals infected with Acrochaetium had a higher defense capacity, whereas the infection with the brown alga did not induce a significant release of phenolic compounds. Despite the heterogeneous results observed for photosynthetic activity, a higher photoinhibition of the maximum fluorescence quantum yield (F-v/F-m) was observed in thalli with the Acrochaetium epiphyte, confirming that G. chilensis was subjected to stress after infection. Taken together, these observations may suggest that the cultivation of females could be of long-term benefit to farms by reducing biomass losses under stressful conditions and epiphyte invasions on farms.
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    First report of the intentionally introduced kelp, Saccharina japonica, in the Pacific coast of southern Chile
    (2022) Camus, Carolina; Leal, Pablo P.; Faugeron, Sylvain; Henriquez-Antipa, Luis A.; Fernandez, Pamela A.; Cook, Sebastian; Carcamo, P. Francisco; Vargas, Jaime
    We report for the first time the occurrence of the Japanese kelp Saccharina japonica on the Pacific coast of southern Chile following an illegal introduction for aquaculture purposes. In November 2020, a citizen complaint indicated that the non-native kelp was being illegally farmed in Canal Caicae ' n. Specimens of the non-native kelp were collected during successive surveys for molecular and morphological analyses, and reproductive viability tests. The species was determined using two mitochondrial molecular markers, COI and trnW-L. Phylogenetic analysis confirmed the taxonomic identity of the specimen as S. japonica and revealed a genetic similarity with S. japonica x S. latissima hybrid cultivars Sanhai and Rongfu. In April 2021, several adult specimens became fertile at the farm site and the laboratory and released meiospores were able to develop into embryos after 15-20 days of incubation. These findings underline the risk for this kelp to disperse and colonize in the natural surrounding habitat, with potential impacts on local coastal ecosystems.
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    Mates Matter: Gametophyte Kinship Recognition and Inbreeding in the Giant Kelp, Macrocystis pyrifera (Laminariales, Phaeophyceae)
    (2021) Camus, Carolina; Solas, Maribel; Martinez, Camila; Vargas, Jaime; Garces, Cristobal; Gil-Kodaka, Patricia; Ladah, Lydia B.; Serrao, Ester A.; Faugeron, Sylvain
    Inbreeding, the mating between genetically related individuals, often results in reduced survival and fecundity of offspring, relative to outcrossing. Yet, high inbreeding rates are commonly observed in seaweeds, suggesting compensatory reproductive traits may affect the costs and benefits of the mating system. We experimentally manipulated inbreeding levels in controlled crossing experiments, using gametophytes from 19 populations of Macrocystis pyrifera along its Eastern Pacific coastal distribution (EPC). The objective was to investigate the effects of male-female kinship on female fecundity and fertility, to estimate inbreeding depression in the F1 progeny, and to assess the variability of these effects among different regions and habitats of the EPC. Results revealed that the presence and kinship of males had a significant effect on fecundity and fertility of female gametophytes. Females left alone or in the presence of sibling males express the highest gametophyte size, number, and size of oogonia, suggesting they were able to sense the presence and the identity of their mates before gamete contact. The opposite trend was observed for the production of embryos per female gametes, indicating higher costs of selfing and parthenogenesis than outcrossing on fertility. However, the increased fecundity compensated for the reduced fertility, leading to a stable overall reproductive output. Inbreeding also affected morphological traits of juvenile sporophytes, but not their heatwave tolerance. The male-female kinship effect was stronger in high-latitude populations, suggesting that females from low-latitude marginal populations might have evolved to mate with any male gamete to guarantee reproductive success.