Two new Nothophytophthora species from streams in Ireland and Northern Ireland: Nothophytophthora irlandica and N. lirii sp. nov.

Slow growing oomycete isolates with morphological resemblance to Phytophthora were obtained from forest streams during routine monitoring for the EU quarantine forest pathogen Phytophthora ramorum in Ireland and Northern Ireland. Internal Transcribed Spacer (ITS) sequence analysis indicated that they belonged to two previously unknown species of Nothophytophthora, a recently erected sister genus of Phytophthora. Morphological and temperature-growth studies were carried out to characterise both new species. In addition, Bayesian and Maximum-Likelihood analyses of nuclear 5-loci and mitochondrial 3-loci datasets were performed to resolve the phylogenetic positions of the two new species. Both species were sterile, formed chlamydospores and partially caducous nonpapillate sporangia, and showed slower growth than any of the six known Nothophytophthora species. In all phylogenetic analyses both species formed distinct, strongly supported clades, closely related to N. chlamydospora and N. valdiviana from Chile. Based on their unique combination of morphological and physiological characters and their distinct phylogenetic positions the two new species are described as Nothophytophthora irlandica sp. nov. and N. lirii sp. nov. Their potential lifestyle and geographic origin are discussed.

Pectobacterium brasiliense: Genomics, Host Range and Disease Management.

Pectobacterium brasiliense (Pbr) is considered as one of the most virulent species among the Pectobacteriaceae. This species has a broad host range within horticulture crops and is well distributed elsewhere. It has been found to be pathogenic not only in the field causing blackleg and soft rot of potato, but it is also transmitted via storage causing soft rot of other vegetables. Genomic analysis and other cost-effective molecular detection methods such as a quantitative polymerase chain reaction (qPCR) are essential to investigate the ecology and pathogenesis of the Pbr. The lack of fast, field deployable point-of-care testing (POCT) methods, specific control strategies and current limited genomic knowledge make management of this species difficult. Thus far, no comprehensive review exists about Pbr, however there is an intense need to research the biology, detection, pathogenicity and management of Pbr, not only because of its fast distribution across Europe and other countries but also due to its increased survival to various climatic conditions. This review outlines the information available in peer-reviewed literature regarding host range, detection methods, genomics, geographical distribution, nomenclature and taxonomical evolution along with some of the possible management and control strategies. In summary, the conclusions and a further directions highlight the management of this species.

Comparative Genomic and Proteomic Analyses of Three Widespread Phytophthora Species: Phytophthora chlamydospora, Phytophthora gonapodyides and Phytophthora pseudosyringae.

The Phytophthora genus includes some of the most devastating plant pathogens. Here we report draft genome sequences for three ubiquitous Phytophthora species-Phytophthora chlamydospora, Phytophthora gonapodyides, and Phytophthora pseudosyringae. Phytophthora pseudosyringae is an important forest pathogen that is abundant in Europe and North America. Phytophthora chlamydospora and Ph. gonapodyides are globally widespread species often associated with aquatic habitats. They are both regarded as opportunistic plant pathogens. The three sequenced genomes range in size from 45 Mb to 61 Mb. Similar to other oomycete species, tandem gene duplication appears to have played an important role in the expansion of effector arsenals. Comparative analysis of carbohydrate-active enzymes (CAZymes) across 44 oomycete genomes indicates that oomycete lifestyles may be linked to CAZyme repertoires. The mitochondrial genome sequence of each species was also determined, and their gene content and genome structure were compared. Using mass spectrometry, we characterised the extracellular proteome of each species and identified large numbers of proteins putatively involved in pathogenicity and osmotrophy. The mycelial proteome of each species was also characterised using mass spectrometry. In total, the expression of approximately 3000 genes per species was validated at the protein level. These genome resources will be valuable for future studies to understand the behaviour of these three widespread Phytophthora species.

Phage cocktail containing Podoviridae and Myoviridae bacteriophages inhibits the growth of Pectobacterium spp. under in vitro and in vivo conditions.

Globally, there is a high economic burden caused by pre- and post-harvest losses in vegetables, fruits and ornamentals due to soft rot diseases. At present, the control methods for these diseases are limited, but there is some promise in developing biological control products for use in Integrated Pest Management. This study sought to formulate a phage cocktail which would be effective against soft rot Pectobacteriaceae species affecting potato (Solanum tuberosum L.), with potential methods of application in agricultural systems, including vacuum-infiltration and soil drench, also tested. Six bacteriophages were isolated and characterized using transmission electron microscopy, and tested against a range of Pectobacterium species that cause soft rot/blackleg of potato. Isolated bacteriophages of the family Podoviridae and Myoviridae were able to control isolates of the Pectobacterium species: Pectobacterium atrosepticum and Pectobacterium carotovorum subsp. carotovorum. Genomic analysis of three Podoviridae phages did not indicate host genes transcripts or proteins encoding toxin or antibiotic resistance genes. These bacteriophages were formulated as a phage cocktail and further experiments showed high activity in vitro and in vivo to suppress Pectobacterium growth, potentially indicating their efficacy in formulation as a microbial pest control agent to use in planta.

Genomic Characterization, Formulation and Efficacy in Planta of a Siphoviridae and Podoviridae Protection Cocktail against the Bacterial Plant Pathogens Pectobacterium spp.

In the face of global human population increases, there is a need for efficacious integrated pest management strategies to improve agricultural production and increase sustainable food production. To counteract significant food loses in crop production, novel, safe and efficacious measures should be tested against bacterial pathogens. Pectobacteriaceae species are one of the causative agents of the bacterial rot of onions ultimately leading to crop losses due to ineffective control measures against these pathogens. Therefore, the aim of this study was to isolate and characterize bacteriophages which could be formulated in a cocktail and implemented in planta under natural environmental conditions. Transmission electron microscopy (TEM) and genome analysis revealed Siphoviridae and Podoviridae family bacteriophages. To test the protective effect of a formulated phage cocktail against soft rot disease, three years of field trials were performed, using three different methods of treatment application. This is the first study to show the application of a phage cocktail containing Podoviridae and Siphoviridae bacteriophages capable of protecting onions against soft rot in field conditions.

Similar taxonomic richness but different communities of ectomycorrhizas in native forests and non-native plantation forests.

This investigation sought to examine if there was a difference between the ectomycorrhizal (ECM) communities in plots of native oak and introduced Scots pine and Sitka spruce forest. The ECM communities in four plots of each forest type were described, from five soil cores collected in each plot, by morphotyping, internal transcribed spacer (ITS)-restriction fragment length polymorphism matching of mycorrhizas and sporocarps and ITS sequencing. Fifty-one distinct taxa were distinguished; 25 were identified to species level, 11 to genus and 15 remained unidentified. Seventy-one ECM species were recorded as sporocarps from the forest plots; most (43 species) were found in the Sitka spruce plots. The below-ground ECM communities of the different forest types did not differ significantly with respect to species richness of taxa on roots, but differed in species composition. Multivariate analysis produced a clear separation of the communities of the different forest types using below-ground data, but the above-ground sporocarp data did not separate the forest types. Moreover, results of a Mantel test found no relationship between the above- and below-ground similarity matrices. The oak plots had the most distinctive ECM community, with Laccaria amethystina and Elaphomyces granulatus being frequent. The Sitka spruce plots showed the lowest intra-forest type similarity and were often dominated by "nursery type" ectomycorrhizas. There was only 10% similarity between the above- and below-ground ECM species in these plots, different colonisation methods of ectomycorrhizal taxa and insufficient below-ground sampling being possible reasons for this disparity. Our results indicate that plantations of non-native Sitka spruce can support similar levels of ECM diversity as native forests.