From high throughput 454 GS FLX data analysis process of 16S RNA gene sequences using barcoding to bacterial community exploration

From high throughput 454 GS FLX data analysis process of 16S RNA gene sequences using barcoding to bacterial community exploratio

The ruminal level of trans-10 fatty acids of dairy cows is linked to the composition of bacterial community

The ruminal level of trans-10 fatty acids of dairy cows is linked to the composition of bacterial communit

Tracking costs of virulence in natural populations of the wheat pathogen, Puccinia striiformis f.sp.tritici

<p>Abstract</p> <p>Background</p> <p>Costs of adaptation play an important role in host-parasite coevolution. For parasites, evolving the ability to circumvent host resistance may trade off with subsequent growth or transmission. Such costs of virulence (<it>sensu </it>plant pathology) limit the spread of all-infectious genotypes and thus facilitate the maintenance of genetic polymorphism in both host and parasite. We investigated costs of three virulence factors in <it>Puccinia striiformis </it>f.sp.<it>tritici</it>, a fungal pathogen of wheat (<it>Triticum aestivum</it>).</p> <p>Results</p> <p>In pairwise competition experiments, we compared the fitness of near-isogenic genotypes that differed by a single virulence factor. Two virulence factors (<it>vir4</it>, <it>vir6</it>) imposed substantial fitness costs in the absence of the corresponding resistance genes. In contrast, the <it>vir9 </it>virulence factor conferred a strong competitive advantage to several isolates, and this for different host cultivars and growing seasons. In part, the experimentally derived fitness costs and benefits are consistent with frequency changes of these virulence factors in the French pathogen population.</p> <p>Conclusion</p> <p>Our results illustrate the variation in the evolutionary trajectories of virulence mutations and the potential role of compensatory mutations. Anticipation of such variable evolutionary outcomes represents a major challenge for plant breeding strategies. More generally, we believe that agro-patho-systems can provide valuable insight in (co)evolutionary processes in host-parasite systems.</p

Development of genetic models to breed for mixed cropping systems

Introduction Mixed cropping, i.e. mixing different crops in the same field, provides agronomic advantages as increased productivity under low inputs conditions (e.g. for organic farming: Bedoussac et al. 2015) and higher yield stability (Raseduzzaman and Jensen 2017). In mixed cropping, choosing the right cultivars is critical for the performance of the mixture, as shown for pea-barley mixtures (Hauggaard-Nielsen and Jensen 2001) and maize-bean mixtures (Hoppe 2016). As performance in pure stand can strongly diverge from performance in mixture, estimating the ability of a cultivar to be mixed with another crop is therefore of utmost importance. For this purpose, concepts of General and Specific Combining Ability in hybrid breeding (Griffing 1956) have been adapted to cultivar and crop mixtures. Thus, these effects are called General Mixing Ability (GMA) and Specific Mixing Ability (SMA) (Federer 1993). In contrast to intraspecific mixtures, interspecific mixed cropping experiments often provide additional information, since harvested lots can be separated into their different grain fractions. Until now, statistical developments mobilizing the additional information provided by separated harvest lots to estimate mixing abilities in intercropping experiments have been neglected. The concept of Producer- and Associate-effects (abbreviated Pr and As, respectively) describes interactions between varieties sown in alternate row trials (Forst 2018). The producer effect Pr is the average performance of a cultivar grown in mixture with other crop-species, whereas the associate effect As is the average effect of a cultivar on the performance of the mixing partner. We used the fraction yields of a spring-pea (Pisum sativum L.) and spring-barley (Hordeum vulgare L.) mixed cropping experiment to determine Pr and As effects of different pea genotypes. The additional information provided by this approach is biologically more informative than GMA/SMA estimates, since it better reflects competition and facilitation occurring between different cultivars of the two crop-species

Innovación para el desarrollo territorial rural con identidad cultural : la experiencia de Sibayo en el Valle del Colca

Parte del informe técnico fina

New breeding strategies for mixed cropping in a barley (H. vulgare L.) pea (P. sativum L.) model system

Crop mixtures consisting of cereals and legumes have proven as a well-adapted arrangement due to their complementarity towards important resources, especially nitrogen. Crop mixtures combine high yield performance and yield stability. They can contribute to a diversified cropping landscape and adaptation to climate change. The search for alternatives to protein imports from overseas and investments in post-harvest separation technologies are currently fostering their adoption by farmers in Western-Europe, especially under organic and lowinput farming conditions. However, screening and breeding for mixed cropping has hardly been explored for arable crops. Thus, the objective was to develop novel breeding strategies and tools specifically for mixed cropping systems. We tested mixtures and pure stands of a morphologically diverse panel of 32 spring pea (Pisum sativum L.) and eight spring barley (Hordeum vulgare L.) cultivars in replicated field trials at two locations in Switzerland over two years with pea as the focal species. In an incomplete factorial design (Fig. 1) we determined general and specific mixing ability (GMA and SMA, respectively) of pea and barley in analogy to GCA and SCA (general and specific combining ability) in hybrid breeding. Key traits, such as early vigour, canopy height and leaf morphology parameters were measured, due to their potential use as covariates or indirect selection criteria for mixing ability. Our results show that total yield of mixtures can only partly be explained by pea pure stand yields (R² = 0.35), making the latter a weak predictor for mixture yield. Pea GMA variance was predominant over SMA variance which underlines the potential for breeding for mixing ability using a tester. Key traits, such as pea stipule area were correlated (R² = 0.56) with total mixture yield and merit further investigation as indirect selection criteria. The separated yield fractions of pea and barley in mixtures allow to decompose GMA of pea into the producer effect of pea cultivar on pea fraction yield and the associate effect of pea on barley fraction yield. This novel concept allows to elucidate key trait effects on fraction yields of pea and barley which might otherwise be masked when solely using a GMA approach

Multiple Infections by the Anther Smut Pathogen Are Frequent and Involve Related Strains

Population models of host–parasite interactions predict that when different parasite genotypes compete within a host for limited resources, those that exploit the host faster will be selected, leading to an increase in parasite virulence. When parasites sharing a host are related, however, kin selection should lead to more cooperative host exploitation that may involve slower rates of parasite reproduction. Despite their potential importance, studies that assess the prevalence of multiple genotype infections in natural populations remain rare, and studies quantifying the relatedness of parasites occurring together as natural multiple infections are particularly scarce. We investigated multiple infections in natural populations of the systemic fungal plant parasite Microbotryum violaceum, the anther smut of Caryophyllaceae, on its host, Silene latifolia. We found that multiple infections can be extremely frequent, with different fungal genotypes found in different stems of single plants. Multiple infections involved parasite genotypes more closely related than would be expected based upon their genetic diversity or due to spatial substructuring within the parasite populations. Together with previous sequential inoculation experiments, our results suggest that M. violaceum actively excludes divergent competitors while tolerating closely related genotypes. Such an exclusion mechanism might explain why multiple infections were less frequent in populations with the highest genetic diversity, which is at odds with intuitive expectations. Thus, these results demonstrate that genetic diversity can influence the prevalence of multiple infections in nature, which will have important consequences for their optimal levels of virulence. Measuring the occurrence of multiple infections and the relatedness among parasites within hosts in natural populations may be important for understanding the evolutionary dynamics of disease, the consequences of vaccine use, and forces driving the population genetic structure of parasites

Die Erbsensorte entscheidet über den Erfolg der Mischung

Sommer-Eiweisserbsen und zweizeilige Gerste sind gute Mischungspartner. Doch gewisse Sortenkombinationen sind besser als andere. Das hat das FiBL in einem zweijährigen Versuch gezeigt

Combined collision-induced dissociation and photo-selected reaction monitoring mass spectrometry modes for simultaneous analysis of coagulation factors and estrogens

AbstractOral estrogens are directly associated with changes in plasma levels of coagulation proteins. Thus, the detection of any variation in protein concentrations due to estrogen contraceptives, by a simultaneous analysis of both coagulation proteins and estrogens, would be a very informative tool. In the present study, the merit of photo-selected reaction monitoring (SRM), a new analytical tool, was evaluated towards estrogens detection in plasma. Then, SRM and photo-SRM detection modes were combined for the simultaneous analysis of estrogen molecules together with heparin co-factor and factor XIIa, two proteins involved in the coagulation cascade. This study shows that photo-SRM could open new multiplexed analytical routes