An Ephemeral Sexual Population of Phytophthora infestans in the Northeastern United States and Canada

Phytophthora infestans, the causal agent of late blight disease, has been reported in North America since the mid-nineteenth century. In the United States the lack of or very limited sexual reproduction has resulted in largely clonal populations of P. infestans. In 2010 and 2011, but not in 2012 or 2013, 20 rare and diverse genotypes of P. infestans were detected in a region that centered around central New York State. The ratio of A1 to A2 mating types among these genotypes was close to the 50:50 ratio expected for sexual recombination. These genotypes were diverse at the glucose-6-phosphate isomerase locus, differed in their microsatellite profiles, showed different banding patterns in a restriction fragment length polymorphism assay using a moderately repetitive and highly polymorphic probe (RG57), were polymorphic for four different nuclear genes and differed in their sensitivity to the systemic fungicide mefenoxam. The null hypothesis of linkage equilibrium was not rejected, which suggests the population could be sexual. These new genotypes were monomorphic in their mitochondrial haplotype that was the same as US-22. Through parentage exclusion testing using microsatellite data and sequences of four nuclear genes, recent dominant lineages US-8, US-11, US-23, and US-24 were excluded as possible parents for these genotypes. Further analyses indicated that US-22 could not be eliminated as a possible parent for 14 of the 20 genotypes. We conclude that US-22 could be a parent of some, but not all, of the new genotypes found in 2010 and 2011. There were at least two other parents for this population and the genotypic characteristics of the other parents were identified

Population Genetics Of Phytophthora Infestans In The United States

Late blight disease caused by Phytophthora infestans continues to pose a great challenge for potato and tomato growers around the world. Despite the numerous efforts conducted to alleviate the losses caused by this disease, the pathogen's diversity has been a key factor in disease control failures. Continuous monitoring of pathogen traits such as fungicide sensitivity and host preference are essential for selecting the best disease mitigation method. The overall objective of this study was to understand the P. infestans population in the USA. More specifically, my research objectives were: i) To characterize the phenotypes of the most recent and most prevalent strains of P. infestans in the US; ii) To investigate a set of rare and diverse genotypes detected in the northeastern US in 2010 and 2011; iii) To study the phenotypic diversity (mating type, host preference, sensitivity to mefenoxam, the effect of temperature on release of zoospores and the effect of temperature on mycelial growth) of a diverse panel of P. infestans from the US, Mexico and the Netherlands and determine the genetic relatedness among them; iv) To conducted a genome-wide association study to identify genetic markers associated with important phenotypic traits; and v) To investigate the characteristics of mefenoxam acquired resistance. Differences in mating type, mefenoxam sensitivity, pathogenicity on potato and tomato, and zoospore release at different temperatures were identified between the recent genotypes of P. infestans in the US (US-8, US-22, US-23, and US-24). The genetic characteristics of the rare and diverse genotypes detected in the northeastern US were consistent with a recombinant population. The phenotypic analyses conducted on strains from the US, Mexico and the Netherlands, revealed a broad range of phenotypic responses. Eleven association hits for mating type in P. infestans where found with a P < 1e-5. The phenomenon of acquired resistance was not unique to certain strains of P. infestans; originally sensitive genotypes US-22, US-23, and US-24 were all able to acquire resistance after a single transfer through mefenoxam containing media. Thirty-two genes were found to be significantly differentially expressed in response to mefenoxam in all originally sensitive genotypes studied

Preparation, Extraction, and Processing of Water-Retted Cannabis Sativa L. Fibers

Cellulose fibers come from fast-growing renewable crops which characteristically are sustainable making them a desirable option for textile structures. Commercial medical Cannabis cultivation is a fast-growing market. Marijuana stems, which are often discarded or burnt, due to the absence of tetrahydrocannabinol (THC) provide an opportunity for the manufacturing of fibers. In this manuscript, the physical, chemical, morphological, and mechanical properties of Cannabis sativa L. stems, coming from medicinal marijuana grown crops, were analyzed to assess their viability for textile use. The content of hemicellulose, pectin, lignin, and cellulose in the fibers was assessed, and we found that the mechanical properties of these fibers are comparable to those of similar natural fibers such as coconut, hemp, sisal, and jute. The FTIR spectra showed all characteristic peaks present in most cellulosic substrates. We demonstrated that cellulosic fibers can be obtained via water-retting of marijuana plants hence opening an avenue for the utilization of agricultural waste in a myriad of potential applications such as water filtration, packaging, and rheological modifiers.Abbreviation: Terms: THC (tetrahydrocannabinol); CBD (cannabidiol); PVC (polyvinyl chlorides); SEM (scanning electron microscopy); FTIR (Fourier transform infrared)

GrünwaldNiklausBotanyPlantPathologyEphemeralSexualPopulation.pdf

Phytophthora infestans, the causal agent of late blight disease, has been reported in North America since the mid-nineteenth century. In the United States the lack of or very limited sexual reproduction has resulted in largely clonal populations of P. infestans. In 2010 and 2011, but not in 2012 or 2013, 20 rare and diverse genotypes of P. infestans were detected in a region that centered around central New York State. The ratio of A1 to A2 mating types among these genotypes was close to the 50:50 ratio expected for sexual recombination. These genotypes were diverse at the glucose-6-phosphate isomerase locus, differed in their microsatellite profiles, showed different banding patterns in a restriction fragment length polymorphism assay using a moderately repetitive and highly polymorphic probe (RG57), were polymorphic for four different nuclear genes and differed in their sensitivity to the systemic fungicide mefenoxam. The null hypothesis of linkage equilibrium was not rejected, which suggests the population could be sexual. These new genotypes were monomorphic in their mitochondrial haplotype that was the same as US-22. Through parentage exclusion testing using microsatellite data and sequences of four nuclear genes, recent dominant lineages US-8, US-11, US-23, and US-24 were excluded as possible parents for these genotypes. Further analyses indicated that US-22 could not be eliminated as a possible parent for 14 of the 20 genotypes. We conclude that US-22 could be a parent of some, but not all, of the new genotypes found in 2010 and 2011. There were at least two other parents for this population and the genotypic characteristics of the other parents were identified

GrünwaldNiklausBotanyPlantPathologyEphemeralSexualPopulation_SupportingInformation.zip

Phytophthora infestans, the causal agent of late blight disease, has been reported in North America since the mid-nineteenth century. In the United States the lack of or very limited sexual reproduction has resulted in largely clonal populations of P. infestans. In 2010 and 2011, but not in 2012 or 2013, 20 rare and diverse genotypes of P. infestans were detected in a region that centered around central New York State. The ratio of A1 to A2 mating types among these genotypes was close to the 50:50 ratio expected for sexual recombination. These genotypes were diverse at the glucose-6-phosphate isomerase locus, differed in their microsatellite profiles, showed different banding patterns in a restriction fragment length polymorphism assay using a moderately repetitive and highly polymorphic probe (RG57), were polymorphic for four different nuclear genes and differed in their sensitivity to the systemic fungicide mefenoxam. The null hypothesis of linkage equilibrium was not rejected, which suggests the population could be sexual. These new genotypes were monomorphic in their mitochondrial haplotype that was the same as US-22. Through parentage exclusion testing using microsatellite data and sequences of four nuclear genes, recent dominant lineages US-8, US-11, US-23, and US-24 were excluded as possible parents for these genotypes. Further analyses indicated that US-22 could not be eliminated as a possible parent for 14 of the 20 genotypes. We conclude that US-22 could be a parent of some, but not all, of the new genotypes found in 2010 and 2011. There were at least two other parents for this population and the genotypic characteristics of the other parents were identified

Network Analyses in Plant Pathogens

Even in the age of big data in Biology, studying the connections between the biological processes and the molecular mechanisms behind them is a challenging task. Systems biology arose as a transversal discipline between biology, chemistry, computer science, mathematics, and physics to facilitate the elucidation of such connections. A scenario, where the application of systems biology constitutes a very powerful tool, is the study of interactions between hosts and pathogens using network approaches. Interactions between pathogenic bacteria and their hosts, both in agricultural and human health contexts are of great interest to researchers worldwide. Large amounts of data have been generated in the last few years within this area of research. However, studies have been relatively limited to simple interactions. This has left great amounts of data that remain to be utilized. Here, we review the main techniques in network analysis and their complementary experimental assays used to investigate bacterial-plant interactions. Other host-pathogen interactions are presented in those cases where few or no examples of plant pathogens exist. Furthermore, we present key results that have been obtained with these techniques and how these can help in the design of new strategies to control bacterial pathogens. The review comprises metabolic simulation, protein-protein interactions, regulatory control of gene expression, host-pathogen modeling, and genome evolution in bacteria. The aim of this review is to offer scientists working on plant-pathogen interactions basic concepts around network biology, as well as an array of techniques that will be useful for a better and more complete interpretation of their data

Metabolomic profile and nucleoside composition of Cordyceps nidus sp. nov. (Cordycipitaceae): A new source of active compounds.

Cordyceps sensu lato is a genus of arthropod-pathogenic fungi, which have been used traditionally as medicinal in Asia. Within the genus, Ophiocordyceps sinensis is the most coveted and expensive species in China. Nevertheless, harvesting wild specimens has become a challenge given that natural populations of the fungus are decreasing and because large-scale culture of it has not yet been achieved. The worldwide demand for products derived from cultivable fungal species with medicinal properties has increased recently. In this study, we propose a new species, Cordyceps nidus, which parasitizes underground nests of trapdoor spiders. This species is phylogenetically related to Cordyceps militaris, Cordyceps pruinosa, and a sibling species of Cordyceps caloceroides. It is found in tropical rainforests from Bolivia, Brazil, Colombia and Ecuador. We also investigated the medicinal potential of this fungus based on its biochemical properties when grown on four different culture media. The metabolic profile particularly that of nucleosides, in polar and non-polar extracts was determined by UPLC, and then correlated to their antimicrobial activity and total phenolic content. The metabolome showed a high and significant dependency on the substrate used for fungal growth. The mass intensities of nucleosides and derivative compounds were higher in natural culture media in comparison to artificial culture media. Among these compounds, cordycepin was the predominant, showing the potential use of this species as an alternative to O. sinensis. Furthermore, methanol fractions showed antimicrobial activity against gram-positive bacteria, and less than 3.00 mg of gallic acid equivalents per g of dried extract were obtained when assessing its total phenolic content by modified Folin-Ciocalteu method. The presence of polyphenols opens the possibility of further exploring the antioxidant capacity and the conditions that may enhance this characteristic. The metabolic composition and biochemical activity indicate potential use of C. nidus in pharmaceutical applications

Bioactive constitutive metabolites extracted from <i>C</i>. <i>nidus</i> with methanol.

<p>The entries in the table are the means and standard deviations of the mass intensities.</p