Genetic analysis and molecular characterisation of laboratory and field mutants of Botryotinia fuckeliana (Botrytis cinerea) resistant to QoI fungicides

BACKGROUND: QoI fungicides, inhibitors of mitochondrial respiration, are considered to be at high risk of resistance development. In several phytopathogenic fungi, resistance is caused by mutations (most frequently G143A) in the mitochondrial cytochrome b (cytb) gene. The genetic and molecular basis of QoI resistance were investigated in laboratory and field mutants of Botryotinia fuckeliana (de Bary) Whetz. exhibiting in vitro reduced sensitivity to trifloxystrobin. RESULTS: B. fuckeliana mutants highly resistant to trifloxystrobin were obtained in the laboratory by spontaneous mutations in wild‐type strains, or from naturally infected plants on a medium amended with 1–3 mg L^?1 trifloxystrobin and 2 mM salicylhydroxamic acid, an inhibitor of alternative oxidase. No point mutations were detected, either in the complete nucleotide sequences of the cytb gene or in those of the aox and Rieske protein genes of laboratory mutants, whereas all field mutants carried the G143A mutation in the mitochondrial cytb gene. QoI resistance was always maternally inherited in ascospore progeny of sexual crosses of field mutants with sensitive reference strains. CONCLUSIONS: The G143A mutation in cytb gene is confirmed to be responsible for field resistance to QoIs in B. fuckeliana. Maternal inheritance of resistance to QoIs in progeny of sexual crosses confirmed that it is caused by extranuclear genetic determinants. In laboratory mutants the heteroplasmic state of mutated mitochondria could likely hamper the G143A detection, otherwise other gene(s) underlying different mechanisms of resistance could be involved. Copyright © 2012 Society of Chemical Industry     

Spatial (Im)mobility and Accessibility in Ireland: Implications for Transport Policy

Recent social research that links people's position in society to their ability to access employment has shown the centrality of spatial mobility in the (re)production of patterns of inequality. This is particularly evident in regions where economic activity is unevenly distributed and concentrated in an urban centre and where daily travel patterns reflect a spatial segregation between places of work and residential areas. This paper presents a spatial analysis of accessibility to employment for Galway City and its environs, a predominantly rural region in the West of Ireland dominated by its urban centre. Travel‐to‐work data from the 2006 Census of Population of Ireland were used to present a comparison of district‐specific accessibility levels across three socio‐economic groups. Network analysis and Geographic Information System visualisation tools are used to map existing socio‐spatial topographies of (in)accessibility. This is done to test two contrasting sets of theoretical proposals in the social science literature regarding the relationship between spatial mobility and social status. Advocates of the first position conceptualise spatial mobility as a form of capital that helps to maintain many existing social hierarchies. This contrasts with the views of those who anticipate the dissolution of established social boundaries (“fluidification”) as a result of increased spatial mobility of people, goods, and ideas. It is argued that these contrasting positions are highly relevant to current transport policy debates, including discussions around the impacts of recession‐related cuts in transport infrastructure investment on patterns of accessibility. In addition, they encourage reflection on the impacts of sustainable transport initiatives on different social groups that are more or less mobility disadvantaged, a fact that has hitherto received little attention in policy research and practice.     

Vp1 expression profiles during kernel development in six genotypes of wheat, triticale and rye

During the last few decades, the physiological and genetic background of dormancy, and correlated pre-harvest sprouting (PHS) have been intensively investigated. Special attention has often been paid to genetic factors that may explain and predict PHS susceptible behaviour. A major candidate is the Vp1 gene which is involved in embryo development and maturation as well as in dormancy establishment. In this study, Vp1 gene expression during kernel development was studied in wheat, triticale and rye as a potential biomarker for selecting PHS tolerant varieties in cereal breeding programs. Plants of known PHS tolerant and PHS susceptible varieties were grown under controlled conditions from flowering until harvest ripeness. During that period, kernels were regularly harvested for RNA extraction and cDNA synthesis. Calibrated and normalized relative Vp1 expression levels were obtained in an RT-qPCR assay. During kernel development, Vp1 expression levels generally showed a typical peak during the soft dough stage, after which they decreased and remained low until harvest maturity. Differences in Vp1 expression levels could be observed between the PHS susceptible and PHS tolerant varieties of wheat, with the PHS tolerant variety showing higher levels of relative Vp1 expression compared to the PHS susceptible variety. In triticale, however, this difference was only seen once and could not be confirmed in further experiments. It seems that the Vp1 gene in triticale behaves in a similar way as in rye, in which no specific trends could be observed.     

Asymmetric segregation of polarized antigen on B cell division shapes presentation capacity

During the activation of humoral immune responses, B cells acquire antigen for subsequent presentation to cognate T cells. Here we show that after mouse B cells accumulate antigen, it is maintained in a polarized distribution for extended periods in vivo. Using high-throughput imaging flow cytometry, we observed that this polarization is preserved during B cell division, promoting asymmetric antigen segregation among progeny. Antigen inheritance correlates with the ability of progeny to activate T cells: Daughter cells receiving larger antigen stores exhibit a prolonged capacity to present antigen, which renders them more effective in competing for T cell help. The generation of progeny with differential capacities for antigen presentation may have implications for somatic hypermutation and class switching during affinity maturation and as B cells commit to effector cell fates.     

Triterpene saponins of Quillaja saponaria show strong aphicidal and deterrent activity against the pea aphid Acyrthosiphon pisum

BACKGROUND: Saponins are a class of secondary plant metabolites consisting of a sugar moiety glycosidically linked to a hydrophobic aglycone (sapogenin) that often possess insecticidal activities. Four saponins were selected: two triterpene saponins, Q. saponaria saponins and aescin, and two steroidal saponins, digitonin and diosgenin. Their effects were investigated on an important pest species and a model piercing‐sucking insect, the pea aphid Acyrthosiphon pisum. The triterpene Q. saponaria saponins bark saponin received special attention because of its high activity. Aphids were challenged by oral and contact exposure to demonstrate aphicidal activities, and in choice experiments to support use as a natural deterrent. RESULTS: When aphids were exposed to supplemented artificial diet for 3 days, a strong aphicidal activity was recorded for three of the four saponins, with an LC₅₀ of 0.55 mg mL^?1 for Q. saponaria saponins, 0.62 mg mL^?1 for aescin and 0.45 mg mL^?1 for digitonin. The LT₅₀ values ranged between 1 and 4 days, depending on the dose. For diosgenin, only low toxicity (14%) was scored for concentrations up to 5 mg mL^?1. In choice experiments with treated diet, a deterrence index of 0.97 was scored for Q. saponaria saponins at 1 mg mL^?1. In contrast, direct contact showed no repellent effect. Spraying of faba bean plants with Q. saponaria saponins resulted in an LC₅₀ of 8.2 mg mL^?1. Finally, histological analysis in aphids fed with Q. saponaria saponins demonstrated strong aberrations of the aphid gut epithelium, and exposure of midgut CF‐203 cell lines to Q. saponaria saponins in vitro confirmed the cytotoxic effect. CONCLUSIONS: The present insect experiments provide strong evidence that saponins, as tested here with triterpene Q. saponaria saponins, can be useful as natural aphicides and deterrents. Furthermore, the insect midgut epithelium is suggested to be a primary target of saponin activity.Copyright © 2011 Society of Chemical Industry     

Protective effects against abortion and fetal infection following exposure to bovine viral diarrhea virus and bovine herpesvirus 1 during pregnancy in beef heifers that received two doses of a multivalent modified-live virus vaccine prior to breeding

Objective-To determine whether administration of 2 doses of a multivalent, modified-live virus vaccine prior to breeding of heifers would provide protection against abortion and fetal infection following exposure of pregnant heifers to cattle persistently infected (PI) with bovine viral diarrhea virus (BVDV) and cattle with acute bovine herpesvirus 1 (BHV1) infection. Design-Randomized controlled clinical trial. Animals-33 crossbred beef heifers, 3 steers, 6 bulls, and 25 calves. Procedures-20 of 22 vaccinated and 10 of 11 unvaccinated heifers became pregnant and were commingled with 3 steers PI with BVDV type 1a, 1b, or 2 for 56 days beginning 102 days after the second vaccination (administered 30 days after the first vaccination). Eighty days following removal of BVDV-PI steers, heifers were commingled with 3 bulls with acute BHV1 infection for 14 days. Results-After BVDV exposure, 1 fetus (not evaluated) was aborted by a vaccinated heifer; BVDV was detected in 0 of 19 calves from vaccinated heifers and in all 4 fetuses (aborted after BHV1 exposure) and 6 calves from unvaccinated heifers. Bovine herpesvirus 1 was not detected in any fetus or calf and associated fetal membranes in either treatment group. Vaccinated heifers had longer gestation periods and calves with greater birth weights, weaning weights, average daily gains, and market value at weaning, compared with those for calves born to unvaccinated heifers. Conclusions and Clinical Relevance-Prebreeding administration of a modified-live virus vaccine to heifers resulted in fewer abortions and BVDV-PI offspring and improved growth and increased market value of weaned calves.