Armillaria mexicana, a newly described species from Mexico.

Armillaria mexicana (Agaricales, Physalacriaceae) is described as a new species based on morphology, DNA sequence data, and phylogenetic analyses. It clearly differs from previously reported Armillaria species in North, Central, and South America. It is characterized by the absence of fibulae in the basidioma, abundant cheilocystidia, and ellipsoidal, hyaline basidiospores that are apparently smooth under light microscope, but slightly to moderately rugulose under scanning electron microscope. It is differentiated from other Armillaria species by macromorphological characters, including annulus structure, pileus and stipe coloration, and other structures. DNA sequence data (nuc rDNA internal transcribed spacers [ITS1-5.8S-ITS2 = ITS], 28S D-domain, 3' end of 28S intergenic spacer 1, and translation elongation factor 1-α [TEF1]) show that A. mexicana sequences are quite distinct from sequences of analogous Armillaria species in GenBank. In addition, sequences of ITS of the A. mexicana ex-type culture reveal an ITS1 of 1299 bp and an ITS2 of 582 bp, the longest ITS regions reported thus far in fungi. Phylogenetic analysis based on TEF1 sequences place A. mexicana in a well-separated, monophyletic clade basal to the polyphyletic A. mellea complex.

High-density genetic mapping identifies the genetic basis of a natural colony morphology mutant in the root rot pathogen Armillaria ostoyae.

Filamentous fungi exhibit a broad spectrum of heritable growth patterns and morphological variations reflecting the adaptation of the different species to distinct ecological niches. But also within species, isolates show considerable variation in growth rates and other morphological characteristics. The genetic basis of this intraspecific variation in mycelial growth and morphology is currently poorly understood. By chance, a growth mutant in the root rot pathogen Armillaria ostoyae was discovered. The mutant phenotype was characterized by extremely compact and slow growth, as well as shorter aerial hyphae and hyphal compartments in comparison to the wildtype phenotype. Genetic analysis revealed that the abnormal phenotype is caused by a recessive mutation, which segregates asa single locus in sexual crosses. In order to identify the genetic basis of the mutant phenotype, we performed a quantitative trait locus (QTL) analysis. A mapping population of 198 haploid progeny was genotyped at 11,700 genome-wide single nucleotide polymorphisms (SNPs) making use of double digest restriction site associated DNA sequencing (ddRADseq). In accordance with the genetic analysis, a single significant QTL was identified for the abnormal growth phenotype. The QTL confidence interval spans a narrow, gene dense region of 87kb in the A. ostoyae genome which contains 37 genes. Overall, our study reports the first high-density genetic map for an Armillaria species and shows its successful application in forward genetics by resolving the genetic basis of a mutant phenotype with a severe defect in hyphal growth.

Incidencia y distribución del género Armillaria en viñedos de las cinco denominaciones de origen de vino de Galicia (noroeste de España) / Incidence and distribution of the genus Armillaria in vineyards of the five protected designation of origin wines in Galicia (Northwestern Spain)

Antecedentes: el género Armillaria, y más concretamente la especie Armillaria mellea, constituye un problema muy importante en el sector vitivinícola de Galicia, lo que ha ocasionado importantes reducciones del rendimiento de los viñedos en los últimos 15 años. Este hongo ataca al sistema radicular, causando un descenso del vigor y, finalmente, la muerte de la planta. Hasta la fecha, no se conoce ningún método químico o biológico que resulte efectivo contra el patógeno una vez que ha entrado en la planta. Objetivos: el objetivo principal del presente trabajo fue conocer la incidencia y distribución del género Armillaria mediante técnicas moleculares en las distintas zonas de cultivo de vid en Galicia, abarcando las cinco denominaciones de origen (DO) vitivinícolas gallegas (Rías Baixas, Ribeiro, Ribeira Sacra, Valdeorras y Monterrei). Métodos: se analizaron 624 muestras (483 de suelo y 141 de plantas de vid sintomáticas) mediante nested-PCR/RFLP, PCR-RFLP y análisis filogenéticos. Resultados: Armillaria mellea está ampliamente distribuida en viñedos de las cinco DO, con mayor incidencia en la DO del Ribeiro. Conclusiones: es necesario establecer medidas para reducir el avance de la podredumbre radicular causada por Armillaria mellea en las cinco DO de Galicia

Blackground: the genus Armillaria, specifically Armillaria mellea, is an important phytopathological problem in the wine sector in Galicia (NW Spain), having caused yield reductions in vineyards for the last 15 years. The fungus attacks the root system, resulting in a decrease in vigour, and eventually in the death of the plant. Up to now, there is no chemical or biological method really effective against the pathogen once it has infected the plant. Aims: the main objective of this work was to study the incidence and distribution of the genus Armillaria across the five Galician protected designation of origin (DO) wines (namely Rías Baixas, Ribeiro, Ribeira Sacra, Valdeorras and Monterrei) through the application of molecular techniques. Methods: a total of 624 samples (483 soils and 141 symptomatic vines) were analyzed by nested-PCR/RFLP, PCR-RFLP and phylogeny. Results: Armillaria mellea is widely distributed in vineyards of the five DO wines, with the highest incidence in the Ribeiro DO. Conclusions: preventive control measures against Armillaria mellea must be established in the five DO wines of Galicia, in order to reduce the advance of white root rot

Chemical, pharmacological, and biological characterization of the culinary-medicinal honey mushroom, Armillaria mellea (Vahl) P. Kumm. (Agaricomycetideae): a review.

Recently, studies have been conducted on the chemical composition of fruiting bodies of the culinary-medicinal Honey mushroom, Armillaria mellea (Vahl.) P. Kumm. (higher Basidiomycetes). It is considered in Europe and Asia as edible and medicinal, when appropriately prepared, and has demonstrated the presence of different groups of organic compounds, including carbohydrates, sterols, sphingolipids, fatty acids, sesquiterpenes, non-hallucinogenic indole compounds, peptides, enzymes, adenosine derivatives, and many other components. Most of these metabolite groups possess potential therapeutic and dietary values. The results of quantitative analyses of indole compounds and heavy metals signal potential health hazards for humans. Some of the studies reviewed herein describe in detail the mechanism of symbiosis between A. mellea and the orchid species Gastrodia elata. This orchid is native to Asia, Australia, and New Zealand, and is used in therapeutics in official Chinese medicine.