Aspergillus sydowii and other potential fungal pathogens in Gorgonian Octocorals of the Ecuadorian Pacific

Emerging fungal diseases are threatening ecosystems and have increased in recent decades. In corals, the prevalence and consequences of these infections have also increased in frequency and severity. Coral reefs are affected by an emerging fungal disease named aspergillosis, caused by Aspergillus sydowii. This disease and its pathogen have been reported along the Caribbean and Pacific coasts of Colombia. Despite this, an important number of coral reefs worldwide have not been investigated for the presence of this pathogen. In this work, we carried out the surveillance of the main coral reef of the Ecuadorian Pacific with a focus on the two most abundant and cosmopolitan species of this ecosystem, Leptogorgia sp. and Leptogorgia obscura. We collected 59 isolates and obtained the corresponding sequences of the Internal Transcribed Spacers (ITS) of the ribosomal DNA. These were phylogenetically analyzed using MrBayes, which indicated the presence of two isolates of the coral reef pathogen A. sydowii, as well as 16 additional species that are potentially pathogenic to corals. Although the analyzed gorgonian specimens appeared healthy, the presence of these pathogens, especially of A. sydowii, alert us to the potential risk to the health and future survival of the Pacific Ecuadorian coral ecosystem under the current scenario of increasing threats and stressors to coral reefs, such as habitat alterations by humans and global climate change.This research was only partially supported by a grant from the Spanish Ministry of Economy and Competitiveness (CTM2014-57949-R).Peer Reviewe

Unravelling the microbiome of eggs of the endangered sea turtle Eretmochelys imbricata identifies bacteria with activity against the emerging pathogen Fusarium falciforme

Habitat bioaugmentation and introduction of protective microbiota have been proposed as potential conservation strategies to rescue endangered mammals and amphibians from emerging diseases. For both strategies, insight into the microbiomes of the endangered species and their habitats is essential. Here, we sampled nests of the endangered sea turtle species Eretmochelys imbricata that were infected with the fungal pathogen Fusarium falciforme. Metagenomic analysis of the bacterial communities associated with the shells of the sea turtle eggs revealed approximately 16,664 operational taxonomic units, with Proteobacteria, Actinobacteria, Firmicutes and Bacteroidetes as the most dominant phyla. Subsequent isolation of Actinobacteria from the eggshells led to the identification of several genera (Streptomyces, Amycolaptosis, Micromomospora Plantactinospora and Solwaraspora) that inhibit hyphal growth of the pathogen F. falciforme. These bacterial genera constitute a first set of microbial indicators to evaluate the potential role of microbiota in conservation of endangered sea turtle species

Unravelling the microbiome of eggs of the endangered sea turtle Eretmochelys imbricata identifies bacteria with activity against the emerging pathogen Fusarium falciforme

Habitat bioaugmentation and introduction of protective microbiota have been proposed as potential conservation strategies to rescue endangered mammals and amphibians from emerging diseases. For both strategies, insight into the microbiomes of the endangered species and their habitats is essential. Here, we sampled nests of the endangered sea turtle species Eretmochelys imbricata that were infected with the fungal pathogen Fusarium falciforme. Metagenomic analysis of the bacterial communities associated with the shells of the sea turtle eggs revealed approximately 16,664 operational taxonomic units, with Proteobacteria, Actinobacteria, Firmicutes and Bacteroidetes as the most dominant phyla. Subsequent isolation of Actinobacteria from the eggshells led to the identification of several genera (Streptomyces, Amycolaptosis, Micromomospora Plantactinospora and Solwaraspora) that inhibit hyphal growth of the pathogen F. falciforme. These bacterial genera constitute a first set of microbial indicators to evaluate the potential role of microbiota in conservation of endangered sea turtle species

Impact of age on susceptibility to aphanomycosis diseases in signal crayfish Pacifastacus leniusculus (Dana, 1852)

The signal crayfish Pacifastacus leniusculus (Dana, 1852) is an American species that was introduced into Spanish rivers. This species carries the fungus responsible for aphanomycosis, Aphanomyces astaci (Schikora), and can transmit it to the native European crayfish species. Although P. leniusculus is often a carrier of this fungus, it generally does not suffer from aphanomycosis; however, if individuals are under stressful conditions, such as the presence of another pathogen or parasite, the chronic infection can develop into an acute, fatal condition. The present paper describes an experiment in which four groups of P. leniusculus, of different ages, were exposed to A. astaci zoospores, in order to compare differences in susceptibility. Our results show that P. leniusculus can die of this disease at concentrations formerly considered sublethal for this species, and also that crayfish juveniles can suffer from this disease. However, significant inter-group differences were not found.El cangrejo señal Pacifastacus leniusculus (Dana, 1852) es una especie americana introducida en España portadora de afanomicosis. Aunque generalmente los cangrejos de esta especie se encuentran infectados por el hongo causante de esta enfermedad, Aphanomyces astaci (Schikora), éstos sólo suelen verse afectados en condiciones de estrés. Entre los factores que predisponen a la afanomicosis destaca la presencia de otras especies parásitas, que pueden hacer que la infección crónica pase a ser aguda y mortal. Dado que hasta la fecha se han realizado muy pocas investigaciones sobre la sensibilidad de esta especie y la influencia de factores como la edad, se realizó un estudio con cuatro grupos de P. leniusculus diferenciados por año de nacimiento. Los cuatros grupos fueron expuestos a zoosporas de A. astaci buscando diferencias en la mortalidad entre los grupos. Los resultados demuestran que P. leniusculus puede padecer la enfermedad, incluso a concentraciones consideradas como subletales y en grupos de edad jóvenes, que hasta ahora se habían descrito como menos susceptibles a la afanomicosis. La diferencia observada entre los grupos no es significativa, lo que no permite concluir que existiera distinta susceptibilidad entre los grupos de edades establecidos.Instituto Español de Oceanografí

Global distribution of two fungal pathogens threatening endangered sea turtles

This work was supported by grants of Ministerio de Ciencia e Innovación, Spain (CGL2009-10032, CGL2012-32934). J.M.S.R was supported by PhD fellowship of the CSIC (JAEPre 0901804). The Natural Environment Research Council and the Biotechnology and Biological Sciences Research Council supported P.V.W. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Thanks Machalilla National Park in Ecuador, Pacuare Nature Reserve in Costa Rica, Foundations Natura 2000 in Cape Verde and Equilibrio Azul in Ecuador, Dr. Jesus Muñoz, Dr. Ian Bell, Dr. Juan Patiño for help and technical support during samplingPeer reviewedPublisher PD

Cell entry of a host-targeting protein of oomycetes requires gp96

The animal-pathogenic oomycete Saprolegnia parasitica causes serious losses in aquaculture by infecting and killing freshwater fish. Like plant-pathogenic oomycetes, S. parasitica employs similar infection structures and secretes effector proteins that translocate into host cells to manipulate the host. Here, we show that the host-targeting protein SpHtp3 enters fish cells in a pathogen-independent manner. This uptake process is guided by a gp96-like receptor and can be inhibited by supramolecular tweezers. The C-terminus of SpHtp3 (containing the amino acid sequence YKARK), and not the N-terminal RxLR motif, is responsible for the uptake into host cells. Following translocation, SpHtp3 is released from vesicles into the cytoplasm by another host-targeting protein where it degrades nucleic acids. The effector translocation mechanism described here, is potentially also relevant for other pathogen-host interactions as gp96 is found in both animals and plants.This work is supported by the [European Community’s] Seventh Framework Programme [FP7/2007–2013] under grant agreement no. [238550] (L.L., J.D.-U., C.J.S., P.v.W.); BBSRC [BBE007120/1, BB/J018333/1 and BB/G012075/1] (F.T., I.d.B., C.J.S., S.W., P.v.W.); Newton Global Partnership Award [BB/N005058/1] (F.T., P.v.W.), the University of Aberdeen (A.D.T., T.R., C.J.S., P.v.W.) and Deutsche Forschungsgemeinschaft [CRC1093] (P.B., T.S.). We would like to acknowledge the Ministry of Higher Education Malaysia for funding INA. We would like to thank Brian Haas for his bioinformatics support. We would like to acknowledge Neil Gow and Johannes van den Boom for critical reading of the manuscript. We would like to acknowledge Svetlana Rezinciuc for technical help with pH-studies

Genomic Characterisation

Peer reviewe

Detection of ‘long-haired’ Saprolegnia (S. parasitica) isolates using monoclonal antibodies

P. 726-733The ability of five monoclonal antibodies (Mabs) raised against a pathogenic Saprolegnia parasitica isolate from brown trout to detect and differentiate between isolates with bundles of long hairs (S. parasitica) and other Saprolegnia species was determined by means of an indirect immunofluorescence assay. Four of the Mabs used recognized some of the long-haired S. parasitica isolates but also cross-reacted with other Saprolegnia species without bundles of hairs and with Achlya sp. The other Mab (named 18A6) was able to differentiate between the asexual and most of the sexual isolates in the group of long-haired S. parasitica isolates, but did not recognize Achlya sp. or the Saprolegnia species without bundles of hairs, with the exception of S. hypogyna. These results indicate that isolates with bundles of long hairs are closely related with other members of genus Saprolegnia and share several antigens. However, Mab 18A6 seems to recognize an epitope that is expressed mainly in the asexual isolates in the long-haired S. parasitica isolates.S

Invasion of fluvial ecosystems by red swamp crayfish, Procambarus clarkii

Trabajo presentado en el International Symposium on Conservation of Native European Freshwater Crayfish, celebrado en Olot (Girona) del 23 al 25 de septiembre de 2015.Biological invasions are one of the biggest threats to biodiversity and conservation of native species, playing a key role in global change. To try to control them, it is important to understand two types of phenomena: mechanisms that allow a species to successfully establish in a new environment, and the ecological, evolutionary and socio-economic consequences of an invasion. We will address both types of phenomena using a multidisciplinary approach and multi-scale research, employing as study model an invasive species of global importance, which has invaded many inland waters: the red swamp crayfish, Procambarus clarkii. In its native area, this species mainly lives in marshes; nevertheless, it has been able to invade a new environment, streams, in invaded areas (in our case: West Andalusia in South Western Spain). Since its introduction over 40 years ago, this invasion is causing serious damage to native species like the European freshwater crayfish, Austropotamobius pallipes. We have five main objectives in this study: (1) to compare the genetic diversity of invasive populations with the native area, identifying patterns of introduction, propagation and gene flow; (2) to determine what mechanisms (at the level of gene expression in different tissues) allow P. clarkii to adapt to new conditions or environmental stress: identify genes and loci responsible for local adaptation; (3) to explore the ecological effects of P. clarkii in streams, in terms of structure and ecosystem functioning, and interactions with populations of native crayfish (A. pallipes) and native amphibians and fishes. To do this, we will compare the ecological effects of stream populations (which have potentially evolved in response to the new environment) with those of founding populations from marshes; (4) to compare the ecological effects of P. clarkii with those of A. pallipes and determine whether the invasive species is occupying the same ecological niche as the native species which has displaced; and (5) to examine the prevalence of Aphanomyces astaci in the red swamp crayfish, given that this invasive species is a chronic carrier of the crayfish plague, aphanomycosis, causing the death of European freshwater crayfish; and that of the fungus that causes chytridiomycosis in amphibians. In this project, we expect to find mechanisms that allow the red swamp crayfish to successfully establish in a new environment and the consequences that this entails for native species.Peer reviewe

Invasión de ecosistemas fluviales por cangrejo rojo americano, Procambarus clarkii

Trabajo presentado en las Jornadas españolas sobre conservación del cangrejo de río autóctono, celebradas el 21 y 22 de septiembre de 2015.Las invasiones biológicas son una de las mayores amenazas para la biodiversidad y conservación de las especies autóctonas, jugando un papel clave en el cambio global. Para intentar controlarlas, es importante entender dos tipos de fenómenos: los mecanismos que permiten a una especie establecerse con éxito en un nuevo ambiente, y las consecuencias ecológicas, evolutivas y económicas de una invasión. Nosotros abordaremos ambos tipos de fenómenos usando un enfoque multidisciplinar y un estudio multiescala, empleando como modelo de estudio una de las especies invasoras con mayor importancia global, la cual ya ha invadido la mayoría de aguas continentales: el cangrejo rojo americano, Procambarus clarkii. En su área nativa, esta especie vive principalmente en marismas; sin embargo, en las áreas invadidas ha sido capaz de invadir un nuevo ambiente, los arroyos, (en nuestro caso: el oeste de Andalucía en el suroeste de España). Desde su introducción hace unos 40 años, esta invasión está causando importantes daños a las especies autóctonas como el cangrejo de río, Austropotamobius pallipes. En este estudio, nos planteamos los siguientes cinco objetivos: (1) comparar la diversidad genética de las poblaciones invasoras con las de las áreas nativas, identificando patrones de introducción, propagación y flujo génico; (2) determinar qué mecanismos (a nivel de expresión de genes en diferentes tejidos) permiten que P. clarkii se adapte a nuevas condiciones o estrés ambiental: identificando genes y loci responsables para la adaptación local; (3) explorar los efectos ecológicos de P. clarkii en arroyos, en términos de estructura y funcionamiento del ecosistema, además de las interacciones con poblaciones nativas, tanto de cangrejo de río (A. pallipes) como de anfibios y peces autóctonos. Para hacer esto, compararemos los efectos ecológicos de las poblaciones de arroyo (las cuales potencialmente han evolucionado en respuesta a nuevos ambientes) con aquellas de poblaciones fundadoras desde las marismas; (4) comparar los efectos ecológicos de P. clarkii con aquellos de A. pallipes y determinar si la especie invasora está ocupando el mismo nicho ecológico que la especie nativa a la cual ha desplazado; y (5) examinar la prevalencia de Aphanomyces astaci en el cangrejo rojo americano, dado que esta especie invasora es portadora de la peste del cangrejo, afanomicosis, causando la muerte del cangrejo de río autóctono; y también la del hongo que causa la quitridiomicosis en anfibios. Con este proyecto, pretendemos dilucidar los mecanismos que permiten al cangrejo rojo americano establecerse exitosamente en un nuevo ambiente y las consecuencias que esto conlleva para las especies autóctonas.Peer reviewe