New foliicolous species of Cladosporium from South America

Two new species of Cladosporium found on necrotic needles of Pinus ponderosa trees in Patagonia, Argentina, are described as C. chubutense and C. pini-ponderosae. An additional isolate from dead leaves of Cortaderia collected in Colombia, which is a sister taxon to the species occurring on Pinus, is described as Cladosporium colombiae. These species are phylogenetically closely related, but differ from each other and other known species by multilocus sequence data, phenetic characters and culture characteristics

Phytophthora austrocedrae

Phytophthora austrocedrae Gresl. & E.M. Hansen (2007) was isolated from necrotic lesions of stem and roots of Austrocedrus chilensis (Cupressaceae). It is homothallic with semi-papillate sporangia, oogonia with amphigynous antheridia, and very slow growth. It is the cause of “mal del ciprés”, a lethal disease of Austrocedrus in Argentina. Austrocedrus chilensis (ciprés de la cordillera) is endemic to southern Argentina and Chile. It is the most widely distributed tree species of the few conifers inhabiting the slopes of the Andes Mountains in Patagonia.Fil: Greslebin, Alina Gabriela. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales y Ciencias de la Salud - Sede Esquel; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Hansen, Eric. State University of Oregon; Estados UnidosFil: la Manna, Ludmila Andrea. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ingeniería - Sede Esquel; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Notes on amylocorticiellum (Amylocorticiales, Basidiomycota), with some new combinations

A review of the known species in Amylocorticiellum is provided. Amylocorticiellum molle is reported as new to Argentina as well to the Southern Hemisphere. Three combinations in Amylocorticiellum, A. iaganicum, A. luteolum, and A. oblongisporum, are proposed, and a key to all accepted species is provided.Fil: Gorjón, Sergio P.. Centro de Investigación y Extensión Forestal Andino Patagónico; ArgentinaFil: Greslebin, Alina Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; ArgentinaFil: Rajchenberg, Mario. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; Argentin

Effect of water potential and host defense on the growth of Amylostereum areolatum and A. chailletii, fungal symbionts of siricides, and study of wood associated mycobiota of conifers in Patagonia, Argentina

Amylostereum areolatum y A. chailletii son los simbiontes fúngicos de las avispas barrenadoras de la madera Sirex noctilio y Urocerus gigas, respectivamente. Las especies de Pinus, son susceptibles al ataque del patosistema S. noctilio - A. areolatum, no obstante en Patagonia, se ha observado que la madera apeada de Pseudotsuga menziesii puede ser atacada por U. gigas y su simbionte. En este estudio se evaluó la relación de A. areolatum, A. chailletii y el potencial agua (Ψ0), la defensa primaria de Pinus ponderosa y Pseudotsuga menziesii, y la micobiota endofítica asociada a ambas coníferas. Los Ψ0 se generaron por variación del potencial osmótico; se extrajeron y caracterizaron por GC y GC-MS los aceites esenciales de las oleorresinas constitutivas de la corteza y la albura de ambas coníferas y se evaluó el efecto de compuestos diferenciales y mayoritarios sobre el crecimiento de ambos hongos; la micobiota se analizó a partir de aislamientos de la albura de plantas sanas. Se observó que, el crecimiento de ambos hongos se ve significativamente afectado por el decrecimiento del Ψ0 y que A. chailletii creció más que A. areolatum en Ψ0 más bajos. Las oleorresinas tuvieron un efecto negativo sobre el crecimiento de ambos hongos sin observarse diferencias entre compuestos diferenciales de cada conífera. Hormonema dematioides fue el endófito más frecuente en P. menziesii, ya caracterizado por su influencia sobre el crecimiento de otros hongos, se presenta como una variable a considerar en cuanto al establecimiento del patosistema S. noctilio- A. areolatumAmylostereum areolatum and A. chailletii are fungal symbionts of wood-boring wasp Sirex noctilio and Urocerus gigas, respectively. Pinus species are susceptible to the S. noctilio - A. areolatum pathosystem, and in Patagonia, Argentina, it was found that the felled wood of Pseudotsuga menziesii can be attacked by U. gigas and its symbiont. This study evaluated the relationship of A. areolatum, A. chailletii and water potential (Ψ0), the primary defense of Pinus ponderosa and P. menziesii, and endophytic mycobiota associated to the wood of both conifers. The different Ψ0 were generated by variations in the osmotic potential; constitutive oleoresins of the bark and sapwood of both softwoods were extracted and characterized by GC and GC-MS and the effect of differential and majority compounds on growth of both fungi were assessed; the mycobiota was analyzed from isolates of the sapwood of healthy plants. It was observed that the growth of both fungi is significantly affected by the decrease of Ψ0 and that A. chailletii grew faster than A. areolatum under lower Ψ0. Oleoresins had a negative effect on the growth of both fungi with no differences between conifers. Hormonema dematioides was the most common endophyte on P. menziesii; this fungus is characterized by its influence on the growth of other fungi and appears as a variable to be considered in setting of S. noctilio - A. areolatum pathosystemFil: López, Sofía Natividad. Centro de Investigación y Extensión Forestal Andino Patagónico; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: Greslebin, Alina Gabriela. Universidad Nacional de la Patagonia "san Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; ArgentinaFil: Gonzalez, Silvia B.. Universidad Nacional de la Patagonia "san Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; ArgentinaFil: Pildain, Maria Belen. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; Argentin

Fungal diversity, woody debris, and wood decomposition in managed and unmanaged Patagonian Nothofagus pumilio forests

Fungal diversity, woody debris, and wood decomposition were assessed in Nothofagus pumilio forests with and without forest management (controls) in Argentina, and were related with the forest structure and microclimate. We established a wood decomposition assay to determine mass loss of branches and twigs in two decay classes (1, incipient and 2, intermediate decay stage), and used generalized linear mixed-effects models to evaluate whether fungal diversity and mass loss differed between treatments (managed forests and controls). We found no differences in richness nor in abundance between treatments, and their community composition was similar. However, Botryobasidium vagum, Phanerochaete velutina, and Sistotrema brinkmanii were more abundant in managed forests, and Amyloathelia aspera was more abundant in controls. Branches in the intermediate decay stage showed greater mass loss in managed forests than in controls, but mass loss of the other debris types did not differ between treatments. The volume of coarse woody debris was greater in managed forests than in controls, and had a positive effect on fungal richness. Our results indicate that N. pumilio forest management did not generate evident changes in fungal diversity, or in wood decomposition after 20 years of the forest management. However, the higher mass loss of branches in the intermediate decay stage observed in managed forests suggests that there were some factors operating in those forests in the past which may have accelerated decomposition. This highlights the need for studies evaluating changes in canopy cover, microclimate, and fungal community, including potential key species, in the short term and the long term after forest management.Fil: Gallo, Ana Laura. Centro de Investigación y Extensión Forestal Andino Patagónico; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Silva, Patricia Valeria. Centro de Investigación y Extensión Forestal Andino Patagónico; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: López Bernal, P.. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: Moretto, Alicia Susana. Universidad Nacional de Tierra del Fuego; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Greslebin, Alina Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagónica. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentin

Phytophthora austrocedri in Argentina and co-Inhabiting phytophthoras: roles of anthropogenic and abiotic factors in species distribution and diversity

This work reports the first survey of Phytophthora diversity in the forests soils of Andean Patagonia. It also discusses the role of anthropogenic impact on Phytophthora distribution inferred from the findings on Phytophthora diversity and on the distribution of Phytophthora austrocedri-diseased forests. Invasive pathogen species threatening ecosystems and human activities contribute to their entry and spread. Information on pathogens already established, and early detection of potential invasive ones, are crucial to disease management and prevention. Phytophthora austrocedri causes the most damaging forest disease in Patagonia, affecting the endemic species Austrocedrus chilensis (D. Don) Pic. Sern. and Bizzarri. However, the relationship between anthropogenic impacts and the disease distribution has not been analyzed enough. The aims of this work were: to evaluate Phytophthora diversity in soils of Andean Patagonia using a metabarcoding method, and analyze this information in relation to soil type and land use; to assess the distribution of Austrocedrus disease over time in relation to anthropogenic and abiotic gradients in an area of interest; and to discuss the role of human activities in Phytophthora spread. High throughput Illumina sequencing was used to detect Phytophthora DNA in soil samples. The distribution of Austrocedrus disease over time was assessed by satellite imagery interpretation. Twenty-three Phytophthora species, 12 of which were new records for Argentina, were detected. The most abundant species was P. austrocedri, followed by P. × cambivora, P. ramorum and P. kernoviae. The most frequent was P. × cambivora, followed by P. austrocedri and P. ramorum. Phytophthora richness and abundance, and Austrocedrus disease distribution, were influenced by land use, anthropogenic impact and soil drainage. Results showed several Phytophthoras, including well-known pathogenic species. The threat they could present to Patagonian ecosystems and their relations to human activities are discussed. This study evidenced the need of management measures to control the spread of P. austrocedri and other invasive Phytophthora species in Patagonia.EEA EsquelFil: Vélez, María Laura. Centro de Investigación y Extensión Forestal Andino Patagónico (CIEFAP); ArgentinaFil: Vélez, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vélez, María Laura. Universidad Nacional de la Patagonia San Juan Bosco; ArgentinaFil: La Manna, Ludmila. Universidad Nacional de la Patagonia San Juan Bosco. Facultad de Ingeniería. Centro de Estudios Ambientales Integrados; ArgentinaFil: La Manna, Ludmila. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tarabini, Manuela. Universidad Nacional de la Patagonia San Juan Bosco. Facultad de Ingeniería. Centro de Estudios Ambientales Integrados; ArgentinaFil: Tarabini, Manuela. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gómez, Federico Antonio. Universidad Nacional de la Patagonia San Juan Bosco. Facultad de Ingeniería. Centro de Estudios Ambientales Integrados; ArgentinaFil: Gómez, Federico Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gómez, Federico Antonio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agroforestal Esquel; ArgentinaFil: Elliott, Matt. Forest Research; EscociaFil: Hedley, Pete. Instituto James Hutton, Cell and Molecular Sciences; Reino UnidoFil: Cock, Peter. Instituto James Hutton, Information and Computational Sciences; Reino UnidoFil: Greslebin, Alina. Centro de Investigación Esquel de Montaña y Estepa Patagónica; ArgentinaFil: Greslebin, Alina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Greslebin, Alina. Universidad Nacional de la Patagonia San Juan Bosco. Facultad de Ciencias Naturales y Ciencias de la Salud; Argentin

Evidence of low levels of genetic diversity for the Phytophthora austrocedrae population in Patagonia, Argentina

Phytophthora austrocedrae is a recently discovered pathogen that causes severe mortality of Austrocedrus chilensis in Patagonia. The high level of susceptibility of the host tree, together with the distribution pattern of the pathogen, have led to the hypothesis that P. austrocedrae was introduced into Argentina. The aim of this study was to assess the population structure of P. austrocedrae isolates from Argentina in order to gain an understanding of the origin and spread of the pathogen. Genetic diversity was determined based on amplified fragment length polymorphisms (AFLPs). In total, 48 isolates of P. austrocedrae were obtained from infected A. chilensis trees, representing the geographical range of the host. Four primer combinations were used for the AFLP analysis. Of the 332 scored bands, 12% were polymorphic. Gene diversity (h) ranged from 0 01 to 0 03; the Shannon index (I) ranged from 0 01 to 0 04. A high degree of genetic similarity was observed among the isolates (pairwise S values = 0 958–1; 0 993 0 009, mean SD). A frequency histogram showed that most of the isolate pairs were identical. Principal coordinate analysis using three-dimensional plots did not group any of the isolates based on their geographical origin. The low genetic diversity (within and between sites) and absence of population structure linked to geographic origin, together with the aggressiveness of the pathogen and the disease progression pattern, suggest that P. austrocedrae might have been introduced into Argentina.The Tree Protection Co-operative Programme (TPCP) and the NRF/DST Centre of Excellence in Tree Health Biotechnology (CTHB), South Africa.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1365-30592015-02-27hb201

Comparison of sapwood invasion by three Phytophthora spp.in different hosts

Many Phytophthora spp. have recently been isolated from native vegetation in Western Australia. As their pathogenicity is often unknown, it is not possible to provide advice to land managers on the impact of site infestation on native plants and how these infestations should be managed. We describe a rapid screening method based on sapwood invasion that has been used to compare the pathogenicity of Phytophthora arenaria, P. cinnamomi and P. multivora. Radial invasion into the xylem of six banksias and three eucalypts was assessed in an excised branch assay in summer and winter. Branches were wound inoculated and invasion was assessed by plating from a strip of tissue cut across the stem at the inoculation point and at 40 mm above and below. A symptomless infection had established in both the bark and sapwood within 6 days. P. arenaria was only isolated from the strip of tissue at the inoculation point. P. cinnamomi was isolated from the sapwood of Banksia attenuata, B. burdettii, B. menziesii and B. speciosa 40 mm above or below the inoculation point in some experiments. P. multivora was isolated from B. speciosa 40 mm below the inoculation point in one experiment. Hyphae of both species were seen in both ray parenchyma cells and xylem vessels. The invasiveness of the Phytophthora spp. was compared on the two groups of hosts using scores for sapwood invasion at the inoculation point. For banksias, P. cinnamomi and P. multivora had significantly higher invasion scores on banksias than P. arenaria but were not significantly different to one another. There was no significant difference between the three Phytophthora spp. on the eucalypt hosts. Assessing sapwood invasion provides a rapid, inexpensive and biologically meaningful way of screening the many Phytophthora spp. that have been isolated from native vegetation