Nucleotide-binding domain and leucine-rich repeat-containing receptors (NLRs) regulate innate immunity by activating inflammatory responses in a variety of biological systems following the recognition of pathogen-or disease-associated molecular patterns. NLRs are characterized by a central nucleotide-binding and oligomerization (NACHT) domain found in P-loop NTPases. In this review, we detail the functional and structural properties of the NACHT domain of a subfamily of NLRs, the NLRPs (NLR containing a pyrin domain), based on previous studies, sequence analysis, homology modeling, and structure predictions. Several NLRPs have been found to regulate inflammatory responses through the assembly of oligomeric caspase 1-activating platforms known as inflammasomes, the 3-dimensional structure of the NLRP NACHT domain has still not been solved. Homology modeling suggests that sequence variability within the NACHT domains of different NLRP family members may alter the topology of the ATP-binding pocket. Based on this finding, we discuss the potential therapeutic prospects aligned with the NACHT domain and the development of selective inhibitors of inflammasome activity. V C 2013 IUBMB Life, 65(10): [851][852][853][854][855][856][857][858][859][860][861][862] 2013

Highlights Grapes are a rich source of bioactive molecules which contribute to the health benefits. Bioactive phytochemicals of grapes include phenolic compounds such as hydroxycinnamic acids, anthocyanins, proanthocyanidins and stilbenes. Grape consumption is linked to reduced incidence of cardiovascular disease and its major risk factors including hypertension. Grapes and its products can be considered as potential functional food in reducing hypertension.

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Summary Opium poppy (Papaver somniferum) remains the sole commercial source for several pharmaceutical alkaloids including the narcotic analgesics codeine and morphine, and the semi‐synthetic drugs oxycodone, buprenorphine and naltrexone. Although most of the biosynthetic genes have been identified, the post‐transcriptional regulation of the morphinan alkaloid pathway has not been determined. We have used virus‐induced gene silencing (VIGS) as a functional genomics tool to investigate the regulation of morphine biosynthesis via a systematic reduction in enzyme levels responsible for the final six steps in the pathway. Specific gene silencing was confirmed at the transcript level by real‐time quantitative PCR (polymerase chain reaction), and at the protein level by immunoblot analysis using antibodies raised against salutaridine synthase (SalSyn), salutaridine reductase (SalR), salutaridine 7‐O‐acetyltransferase (SalAT), thebaine 6‐O‐demethylase (T6ODM), codeinone reductase (COR), and codeine O‐demethylase (CODM). In some cases, silencing a specific biosynthetic gene resulted in a predictable accumulation of the substrate for the corresponding enzyme. Reduced SalSyn, SalR, T6ODM and CODM protein levels correlated with lower morphine levels and a substantial increase in the accumulation of reticuline, salutaridine, thebaine and codeine, respectively. In contrast, the silencing of genes encoding SalAT and COR resulted in the accumulation of salutaridine and reticuline, respectively, which are not the corresponding enzymatic substrates. The silencing of alkaloid biosynthetic genes using VIGS confirms the physiological function of enzymes previously characterized in vitro, provides insight into the biochemical regulation of morphine biosynthesis, and demonstrates the immense potential for metabolic engineering in opium poppy.

The late blight pathogen (Phytophthora infestans) continues to cause major losses on potato and tomato in Canada and worldwide. An increased diversity of P. infestans and dramatic shifts in pathogen populations have occurred in Canada in recent years. In 2011, a survey identified different genotypes of P. infestans in Canada, including the new US-22, US-23 and US-24 genotypes, which were dominant in various Canadian provinces. In 2012, analysis of samples collected from infected potato and tomato plants from different regions in Canada indicated a rapid change in P. infestans populations in most provinces within a single year. For example, in Prince Edward Island, the US-8 genotype that dominated the P. infestans landscape for many years was displaced by the US-23 genotype, a phenomenon similar to that which occurred in western Canada in prior years. In British Columbia, however, US-11 and the new CA-12 were the dominant genotypes while in Ontario the tested isolates were US-22. Evidence for recombination was found, and increasing insensitivity to mefenoxam was apparent among isolates of some populations. Independent segregation of either Gpi, mating type or RG57 loci occurred in a number of the recombinant isolates, resulting in increased diversity of P. infestans populations. The unexpected change in composition of P. infestans genotypes supports the need for continued monitoring of this pathogen.Résumé: L'agent pathogène causant le mildiou (Phytophthora infestans) continue de causer des dommages importants aux cultures de pommes de terre et de tomates au Canada et partout dans le monde. Au cours des dernières années, au Canada, nous avons observé une augmentation de la diversité et des changements spectaculaires de populations chez P. infestans. En 2011, une étude canadienne a permis d'identifier différents génotypes de P. infestans, y compris les nouveaux génotypes US-22, US-23 et US-24 qui prédominaient dans différentes provinces. En 2012, une analyse d'échantillons collectés sur des plants infectés de pomme de terre et de tomate provenant de diverses régions du Canada a indiqué, au cours d'une seule année, un changement rapide dans les populations de P. infestans, et ce, dans la plupart des provinces. Par exemple, à l'Île-du-Prince-Édouard, le génotype US-8, qui avait pendant longtemps dominé les populations de ce pathogène, a été détrôné par le génotype US-23, phénomène semblable à celui qui s'était produit dans l'Ouest canadien quelques années auparavant. Toutefois, en Colombie-Britannique, le génotype US-11 et le nouveau génotype CA-12 dominaient, tandis qu'en Ontario, les isolats testés correspondaient au génotype US-22. Des preuves relatives à la recombinaison ont été décelées et, parmi les isolats de certaines populations, une insensibilité accrue au méfénoxam s'est avérée de plus en plus évidente. La libre ségrégation du Gpi, du type sexuel ou du locus RG57 s'est produite chez plusieurs isolats recombinants, ce qui a entraîné une augmentation de la diversité des populations de P. infestans. Les chang...

Late blight, caused by Phytophthora infestans (Mont.) de Bary, is the most historically significant and economically destructive disease of potatoes (Solanum tuberosum L.). In addition to potato, P. infestans can also infect tomato and some other members of the Solanaceae, and this has contributed to the recent late blight epidemic in Canada and the United States. Propagation of P. infestans in Canada and the United States has been mainly through asexual reproduction and this has led to the development of several dominant clonal lineages. Various P. infestans markers have been developed that are invaluable in monitoring the evolution and movement of these P. infestans genotypes. Population diversity and disease incidence has increased through the development of systemic fungicide insensitivity and the transcontinental shipment of the pathogen on late blight infected potato tubers and tomato plantlets. Introduction of the P. infestans A2 mating type to several regions of Canada and the United States has also increased the opportunity for sexual reproduction and recombination, potentially contributing to greater P. infestans genetic diversity and pathogenicity. Advances in P. infestans molecular analysis have revealed a complex pathogen with a genome capable of evolving relatively quickly. Management of late blight will therefore require new, multifaceted strategies which include monitoring pathogen evolution and implementing sustainable production practices.Resumen El tizón tardío, causado por Phytophthora infestans (Mont.) de Bary, es la enfermedad históricamente más significativa y económicamente destructiva de papa (Solanum tuberosum L.). Además de la papa, P. infestans también puede infectar tomate y a otros miembros de la familia Solanaceae, y esto ha contribuido a la reciente epidemia de tizón tardío en Canadá y los Estados Unidos. La propagación de P.infestans en estos dos países ha sido principalmente mediante reproducción asexual, lo que ha conducido al desarrollo de varias líneas clonales dominantes. Se han desarrollado varios marcadores para P. infestans que son invaluables en el seguimiento de la evolución y movimiento de estos genotipos de P. infestans. La diversidad de la población y la incidencia de la enfermedad han aumentado por vía del desarrollo de la insensibilidad a fungicidas sistémicos y del envío transcontinental del patógeno en tubérculos de papa infectados con tizón tardío y en plántulas de tomate. La introducción del tipo de compatibilidad A2 de P. infestans a varias regiones de Canadá y Estados Unidos también ha incrementado la oportunidad de reproducción sexual y recombinación, contribuyendo, potencialmente, a una mayor diversidad genética y patogenicidad de P. infestans. Avances en los análisis moleculares de P. infestans han revelado a un patógeno complejo con un genomio capaz de evolucionar relativamente rápido. El manejo del tizón tardío, entonces, requerirá de nuevas estrategias multifacéticas que incluyan monitoreo de la evolución del patógeno y la implementación de prá...

Plant fungal endophytes are diverse microbial sources that reside inside the plants. Grapes (Vitis vinifera) are rich in polyphenols with health benefits and recent research showed fungal endophytes in grapes may contribute to the production of these polyphenols and as biocontrol agents. In this study, we determined the fungal microbial endophyte diversity in fruit of the North American table grapes found in Winnipeg market. Amplicon ITS (internal transcribed spacer) metagenomics approach was used to profile the fungal communities of the fruit endophyte microbiome of three table grape types. The data supported endophyte diversity in different table grapes including possible bioactive producing, saprophytic, and pathogenic fungi. Culturable endophytes were isolated and identified by morphology and ITS-amplicon sequencing. Majority of the isolated culturable strains included Alternaria spp and Cladosporium spp. The results provided evidence of diverse fungal endophytes isolated and identified from the fruit of the table grapes and these fungal endophytes may have potential in agricultural, industrial, and pharmaceutical applications.

Virus-induced gene silencing (VIGS) is a rapid reverse genetics tool that has been developed in a wide variety of plant species for assessing gene functions. However, while VIGS has been utilized successfully in the diploid model leguminous species Medicago truncatula (Gaertn.) (barrel medic), such a platform has yet to be established in forage legume crop species. Therefore, we evaluated the effectiveness of this method in forage legumes using a previously developed PEBV (pea early browning virus) system whereby a fragment of the pea (Pisum sativum L.) PHYTOENE DESATURASE (PDS) gene was transferred into a range of alfalfa (Medicago sativa L.), sainfoin (Onobrychis viciifolia Scop.), and fenugreek (Trigonella foenum-graecum L.) cultivars using leaf infiltration and apical meristem injection. Barrel medic was used as a positive control. Gene silencing was observed after 10–15 d through the presence of a leaf bleaching phenotype, and was confirmed using quantitative real-time RT-PCR. Silencing of PDS was achieved in a selection of cultivars in all species assessed, with the highest silencing efficiency apparent in fenugreek. The introduction of a highly homologous gene fragment from a heterologous plant species to target endogenous genes for transient VIGS-based silencing in a range of species of interest represents a potentially useful strategy for the rapid functional characterization of candidate genes in forages.