Identification of glutathione transferase gene associated with partial resistance to Sclerotinia stem rot of soybean using genome-wide association and linkage mapping.

KEY MESSAGE: Association and linkage mapping techniques were used to identify and verify single nucleotide polymorphisms (SNPs) associated with Sclerotinia sclerotiorum resistance. A novel resistant gene, GmGST , was cloned and shown to be involved in soybean resistance to SSR. Sclerotinia stem rot (SSR), caused by the fungus Sclerotinia sclerotiorum, is one of the most devastating diseases in soybean (Glycine max (Linn.) Merr.) However, the genetic architecture underlying soybean resistance to SSR is poorly understood, despite several mapping and gene mining studies. In the present study, the identification of quantitative trait loci (QTLs) involved in the resistance to S. sclerotiorum was conducted in two segregating populations: an association population that consisted of 261 diverse soybean germplasms, and the MH population, derived from a cross between a partially resistant cultivar (Maple arrow) and a susceptible cultivar (Hefeng25). Three and five genomic regions affecting resistance were detected by genome-wide association study to control the lesion length of stems (LLS) and the death rate of seedling (DRS), respectively. Four QTLs were detected to underlie LLS, and one QTL controlled DRS after SSR infection. A major locus on chromosome (Chr.) 13 (qDRS13-1), which affected both DRS and LLS, was detected in both the natural population and the MH population. GmGST, encoding a glutathione S-transferase, was cloned as a candidate gene in qDRS13-1. GmGST was upregulated by the induction of the partially resistant cultivar Maple arrow. Transgenic experiments showed that the overexpression of GmGST in soybean increased resistance to S. sclerotiorum and the content of soluble pigment in stems of soybean. The results increase our understanding of the genetic architecture of soybean resistance to SSR and provide a framework for the future marker-assisted breeding of resistant soybean cultivars.

Outgrowing the Immaturity Myth: The Cost of Defending From Neonatal Infectious Disease.

Newborns suffer high rates of mortality due to infectious disease-this has been generally regarded to be the result of an "immature" immune system with a diminished disease-fighting capacity. However, the immaturity dogma fails to explain (i) greater pro-inflammatory responses than adults in vivo and (ii) the ability of neonates to survive a significantly higher blood pathogen burden than of adults. To reconcile the apparent contradiction of clinical susceptibility to disease and the host immune response findings when contrasting newborn to adult, it will be essential to capture the entirety of available host-defense strategies at the newborn's disposal. Adults focus heavily on the disease resistance approach: pathogen reduction and elimination. Newborn hyperactive innate immunity, sensitivity to immunopathology, and the energetic requirements of growth and development (immune and energy costs), however, preclude them from having an adult-like resistance response. Instead, newborns also may avail themselves of disease tolerance (minimizing immunopathology without reducing pathogen load), as a disease tolerance approach provides a counterbalance to the dangers of a heightened innate immunity and has lower-associated immune costs. Further, disease tolerance allows for the establishment of a commensal bacterial community without mounting an unnecessarily dangerous immune resistance response. Since disease tolerance has its own associated costs (immune suppression leading to unchecked pathogen proliferation), it is the maintenance of homeostasis between disease tolerance and disease resistance that is critical to safe and effective defense against infections in early life. This paradigm is consistent with nearly all of the existing evidence.

Innate Immunity Provides Biomarkers of Health for Teleosts Exposed to Nanoparticles.

In recent years, the unique properties of nanoparticles have fostered novel applications in various fields such as biology, pharmaceuticals, agriculture, and others. Unfortunately, their rapid integration into daily life has also led to environmental concerns due to uncontrolled release of nanoparticles into the aquatic environment. Despite increasing awareness of nanoparticle bioaccumulation in the aquatic environment, much remains to be learned about their impact on aquatic organisms and how to best monitor these effects. Herein, we provide the first review of innate immunity as an emerging tool to assess the health of fish following nanoparticle exposure. Fish are widely used as sentinels for aquatic ecosystem pollution and innate immune parameters offer sensitive and reliable tools that can be harnessed for evaluation of contamination events. The most frequent biomarkers highlighted in literature to date include, but are not limited to, parameters associated with leukocyte dynamics, oxidative stress, and cytokine production. Taken together, innate immunity offers finite and sensitive biomarkers for assessment of the impact of nanoparticles on fish health.

Parallel and costly changes to cellular immunity underlie the evolution of parasitoid resistance in three Drosophila species.

A priority for biomedical research is to understand the causes of variation in susceptibility to infection. To investigate genetic variation in a model system, we used flies collected from single populations of three different species of Drosophila and artificially selected them for resistance to the parasitoid wasp Leptopilina boulardi, and found that survival rates increased 3 to 30 fold within 6 generations. Resistance in all three species involves a large increase in the number of the circulating hemocytes that kill parasitoids. However, the different species achieve this in different ways, with D. melanogaster moving sessile hemocytes into circulation while the other species simply produce more cells. Therefore, the convergent evolution of the immune phenotype has different developmental bases. These changes are costly, as resistant populations of all three species had greatly reduced larval survival. In all three species resistance is only costly when food is in short supply, and resistance was rapidly lost from D. melanogaster populations when food is restricted. Furthermore, evolving resistance to L. boulardi resulted in cross-resistance against other parasitoids. Therefore, whether a population evolves resistance will depend on ecological conditions including food availability and the presence of different parasite species.

Assessment of immune status of yellowfin seabream (Acanthopagrus latus) during short term exposure to phenanthrene.

The aim of the present investigation was to assess the immune status in yellowfin seabream (Acanthopagrus latus) exposed to different concentrations of phenanthrene (Phe) for 14days. In addition, the Phe accumulation in the fish muscle was measured during the experiment. Fish were injected with different concentrations (0, 2, 20 and 40mg/kg) of Phe and samples were taken from tissue and blood of fish 1, 4, 7 and 14days after injection. Exposure of fish to Phe caused a significant decrease in white blood cells, C3 and C4 levels, lysosomal membrane stability, lysozyme activity after 4days and antibacterial activity after 7days of the experiment. In contrast, cortisol level significantly increased after 4days. The concentration of Phe in fish muscle increased rapidly after 4days. The main tissue changes observed in the head kidney including increase in melanomacrophage centers (MMCs), empty spaces between cells and hemorrhage. The degree of tissue changes ranged from normal to moderate in Phe-treated fish. The size and number of MMCs in treated fish were significantly higher than control. In conclusion, Phe toxicity in yellowfin seabream can induce increased cortisol level, tissue changes and immune suppression.

Ex-Ante Economic Impact Assessment of Genetically Modified Banana Resistant to Xanthomonas Wilt in the Great Lakes Region of Africa.

BACKGROUND: Credible empirical evidence is scanty on the social implications of genetically modified (GM) crops in Africa, especially on vegetatively propagated crops. Little is known about the future success of introducing GM technologies into staple crops such as bananas, which are widely produced and consumed in the Great Lakes Region of Africa (GLA). GM banana has a potential to control the destructive banana Xanthomonas wilt disease. OBJECTIVE: To gain a better understanding of future adoption and consumption of GM banana in the GLA countries which are yet to permit the production of GM crops; specifically, to evaluate the potential economic impacts of GM cultivars resistant to banana Xanthomonas wilt disease. DATA SOURCES: The paper uses data collected from farmers, traders, agricultural extension agents and key informants in the GLA. ANALYSIS: We analyze the perceptions of the respondents about the adoption and consumption of GM crop. Economic surplus model is used to determine future economic benefits and costs of producing GM banana. RESULTS: On the release of GM banana for commercialization, the expected initial adoption rate ranges from 21 to 70%, while the ceiling adoption rate is up to 100%. Investment in the development of GM banana is economically viable. However, aggregate benefits vary substantially across the target countries ranging from US$ 20 million to 953 million, highest in countries where disease incidence and production losses are high, ranging from 51 to 83% of production. CONCLUSION: The findings support investment in the development of GM banana resistant to Xanthomonas wilt disease. The main beneficiaries of this technology development are farmers and consumers, although the latter benefit more than the former from reduced prices. Designing a participatory breeding program involving farmers and consumers signifies the successful adoption and consumption of GM banana in the target countries.

Estratégias para prevenção da resistência bacteriana: contribuições para a segurança do paciente / Estrategias para prevención de resistencia bacteriana: contribuciones para la seguridad del paciente / Strategies for prevention of bacterial resistance: contributions to patient safety

Introdução: A resistência bacteriana tem como consequências, o aumento da morbidade, mortalidade e da internação hospitalar, o prolongamento das doenças, a perda da produtividade, o aumento dos custos e maior risco de complicações. Materiais e Métodos: Trata-se de um estudo descritivo, com abordagem qualitativa, na perspectiva de uma revisão integrativa da literatura, realizada em janeiro de 2014. Resultados e Discussão: Foram selecionados oito artigos que relatavam estratégias de prevenção da resistência bacteriana em um recorte temporal de 2008 a 2014. O uso racional de antimicrobianos, a higienização adequada das mãos, a cultura de vigilância microbiológica, a educação continuada, a desinfecção de superfícies, uso de testes de suscetibilidade, o isolamento de contato, quando indicado e a manutenção de um banco de dados, são alguns dos métodos encontrados neste trabalho para prevenir a seleção de micro-organismos resistentes. Conclusões: A diminuição do lançamento de novos antimicrobianos pela indústria farmacêutica e a necessidade de novos antibióticos reforça ainda mais a importância da conscientização de toda a equipe multidisciplinar no processo de prevenção de resistência antimicrobiana.

Introducción: La resistencia bacteriana tiene como consecuencias, el aumento de morbilidad, mortalidad y de hospitalización, prolongación de enfermedades, pérdida de productividad, aumento de los costos y mayor riesgo de complicaciones. Materiales y Métodos: Este es un estudio descriptivo con un enfoque cualitativo, en la perspectiva de una revisión integradora de la literatura, realizada en enero del 2014. Resultados y Discusión: Fueron seleccionados ocho artículos que reportan estrategias de prevención de la resistencia bacteriana en un periodo de tiempo del 2008 a 2014. El uso racional de antimicrobianos, la higiene adecuada de las manos, la cultura de vigilancia microbiológica, la educación continuada, la desinfección de superficies, el uso de pruebas de susceptibilidad, aislamiento del contacto, cuando esté indicado y el mantenimiento de una base de datos, son algunos de los métodos encontrados en este trabajo para evitar la selección de microorganismos resistentes. Conclusiones: La disminución en la liberación de nuevos antimicrobianos por la industria farmacéutica y la necesidad de nuevos antibióticos refuerza la importancia de la concientización de todo el equipo multidisciplinario en el proceso de prevención de la resistencia antimicrobiana.

Introduction: Bacterial resistance has as consequences, increased morbidity, mortality and hospitalization, the prolongation of disease, loss of productivity, increased costs and greater risk of complications. Material and Methods: This is a descriptive study with a qualitative approach, from the perspective of a integrative review of literature, held in January 2014. Results and discussion: Were selected eight articles that reported bacterial resistance prevention strategies in a timeframe of 2008 to 2014. The rational use of antimicrobials, proper hand hygiene, microbiological surveillance culture, continuing education, disinfection of surfaces, use of susceptibility tests, contact isolation, when indicated and the maintenance of a database, are some of the methods found in this work to prevent the selection of resistant microorganisms. Conclusions: the decrease in the release of new antimicrobials by the pharmaceutical industry and the need for new antibiotics further strengthens the importance of the awareness of the entire multidisciplinary team in the process of prevention of antimicrobial resistance.

Assessment of genetic correlation between bacterial cold water disease resistance and spleen index in a domesticated population of rainbow trout: identification of QTL on chromosome Omy19.

Selective breeding of animals for increased disease resistance is an effective strategy to reduce mortality in aquaculture. However, implementation of selective breeding programs is limited by an incomplete understanding of host resistance traits. We previously reported results of a rainbow trout selection program that demonstrated increased survival following challenge with Flavobacterium psychrophilum, the causative agent of bacterial cold water disease (BCWD). Mechanistic study of disease resistance identified a positive phenotypic correlation between post-challenge survival and spleen somatic-index (SI). Herein, we investigated the hypothesis of a genetic correlation between the two traits influenced by colocalizing QTL. We evaluated the inheritance and calculated the genetic correlation in five year-classes of odd- and even-year breeding lines. A total of 322 pedigreed families (n = 25,369 fish) were measured for disease resistance, and 251 families (n = 5,645 fish) were evaluated for SI. Spleen index was moderately heritable in both even-year (h(2)  = 0.56±0.18) and odd-year (h(2)  = 0.60±0.15) lines. A significant genetic correlation between SI and BCWD resistance was observed in the even-year line (rg  = 0.45±0.20, P = 0.03) but not in the odd-year line (rg  = 0.16±0.12, P = 0.19). Complex segregation analyses of the even-year line provided evidence of genes with major effect on SI, and a genome scan of a single family, 2008132, detected three significant QTL on chromosomes Omy19, 16 and 5, in addition to ten suggestive QTL. A separate chromosome scan for disease resistance in family 2008132 identified a significant BCWD QTL on Omy19 that was associated with time to death and percent survival. In family 2008132, Omy19 microsatellite alleles that associated with higher disease resistance also associated with increased spleen size raising the hypothesis that closely linked QTL contribute to the correlation between these traits. To our knowledge, this is the first estimation of spleen size heritability and evidence for genetic linkage with specific disease resistance in a teleost fish.