Metagenomic discovery of biomass-degrading genes and genomes from cow rumen     

Hess M  Sczyrba A  Egan R  Kim TW  Chokhawala H  Schroth G  Luo S  Clark DS  Chen F  Zhang T  Mackie RI  Pennacchio LA  Tringe SG  Visel A  Woyke T  Wang Z  Rubin EM 《Science (New York, N.Y.)》2011,331(6016):463-467

The paucity of enzymes that efficiently deconstruct plant polysaccharides represents a major bottleneck for industrial-scale conversion of cellulosic biomass into biofuels. Cow rumen microbes specialize in degradation of cellulosic plant material, but most members of this complex community resist cultivation. To characterize biomass-degrading genes and genomes, we sequenced and analyzed 268 gigabases of metagenomic DNA from microbes adherent to plant fiber incubated in cow rumen. From these data, we identified 27,755 putative carbohydrate-active genes and expressed 90 candidate proteins, of which 57% were enzymatically active against cellulosic substrates. We also assembled 15 uncultured microbial genomes, which were validated by complementary methods including single-cell genome sequencing. These data sets provide a substantially expanded catalog of genes and genomes participating in the deconstruction of cellulosic biomass.  相似文献   

Ex situ collections of cultivated flax (<Emphasis Type="Italic">Linum usitatissimum</Emphasis> L.) and other species of the genus <Emphasis Type="Italic">Linum</Emphasis> L.     

Axel Diederichsen 《Genetic Resources and Crop Evolution》2007,54(3):661-678

An overview of ex situ collections of cultivated flax (Linum usitatissimum L.) and 53 other species of the genus Linum L. is presented. The names of 33 genebanks in 23 countries preserving Linum germplasm and the species preserved at these places are provided. World genebanks engage in ex situ preservation of about 48,000 accessions of cultivated flax (Linum usitatissimum). However, possibly only 10,000 accessions of these are unique. Of the ca. 200 species of the genus Linum, other than L. usitatissimum, 53 are reported to be represented in the world’s ex situ collections with a total of about 900 accessions. Of these, 279 accessions alone refer to the wild progenitor of cultivated flax, Linum bienne Mill. However, L. bienne from the region of origin of cultivated flax is rarely represented in genebank collections. References to publications describing the techniques for ex situ conservation and the infraspecific variation of cultivated flax are made. It is suggested that taxonomic species delimitation within the genus Linum is in need of clarification and that the variation in Linum species for ornamental use or use in breeding is investigated.  相似文献   

The infraspecific taxa of coriander (Coriandrum sativum L.)     

A. Diederichsen  K. Hammer 《Genetic Resources and Crop Evolution》2003,50(1):33-63

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Soil exploration,nutrient partitioning,and nutrient efficiency of beech and spruce seedlings in a rhizotrone experiment     

Zhenyu Wang  Axel Gttlein  Hermann Rodenkirchen 《植物养料与土壤学杂志》2003,166(3):390-391

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Effect of adjacent agricultural habitat on the distribution of passerines in natural grasslands     

Lluís Brotons  Axel Wolff  Jean-Louis Martin 《Biological conservation》2005,124(3):407-414

Habitat heterogeneity has often been acknowledged as a key factor determining which species occur in a landscape, but we still know little on the nature and relative importance of the processes controlling species distribution and abundance within complex landscape mosaics. We used a framework defined by the compensation, supplementation and complementation models to study the distribution of four species of passerines typical of steppe habitats and identify the degree to which landscape context accounts for their distribution in the steppe-agriculture mosaic of the Crau, southern France. Steppe habitat was the best predictor of species distribution in all cases and that densities were highest in steppe. One of these species, the Calandra lark, is strictly tied to the natural steppe habitats independently of its context. For another species, the Tawny pipit, we document a significant positive effect of the presence, near steppe habitat, of extensive pastoral habitats, such as fallows and grazed crops. Finally, the abundance of the two remaining species, Skylark and Short-toed lark, was negatively affected by the presence of non-herbaceous habitats in the vicinity of steppe habitat. This suggests that the quality of the steppe habitat, as perceived by these species is conditional to the nature of adjacent habitats. Our results suggest that the management of the context in which steppe habitat is imbedded will significantly affect the distribution and abundance of this group of passerines and determine both habitat quality and conservation value at a landscape scale.  相似文献   

In situ and on-farm management of plant genetic resources     

K. Hammer  Th. Gladis  A. Diederichsen   《European Journal of Agronomy》2003,19(4):509-517

For establishing an effective maintaining programme for plant genetic resources (PGR), an integrated system is necessary considering the three principal ways of germplasm management—ex situ, in situ and on-farm. The scientific concept for on-farm conservation is relatively new and desires a special discussion. Differences in conservation and management strategies are defined here with respect to three countries. Germany is used as an example for an industrialized country, relatively poor in landraces. Italy may suit as example for an industrialized country with high diversity in agricultural products and production techniques, and Cuba is an example for a tropical country, scarcely industrialized and extremely rich in PGR. The following categories of countries are defined here: (a) Category 1: country e.g. Cuba; (b) Category 2: country e.g. Italy; (c) Category 3: country e.g. Germany. The definition of specific categories with respect to the different situations of these countries is extremely helpful in valuation of ex situ, in situ and on-farm measures regarding their effectiveness and necessary finances in the context of realization of the requests of the Convention on Biological Diversity to protect the diversity in countries and regions. First of all, management of germplasm including breeding and selection in the hands of the farmers has to be secured. On-farm management is a dynamic approach and the present expectations to this are high and tend to overload this concept. More realistic is an integrated approach considering the respective country and local conditions including farmers’ preferences and application of all conservation systems.  相似文献   

Comparisons of Isozyme Patterns in Resynthesized Amphihaploid Rapeseed (Brassica napus) and Their Parental Species Brassica campestris and Brassica oleracea     

Hiltrud  Mündges  Elke  Diederichsen W. Köhler 《Plant Breeding》1989,103(3):258-261

Resynthesized rapeseed plants produced by embryo culture and the progeny of their selfed parents from Brassica oleracea and Brassica campestris were analyzed by starch gel electrophoresis staining of enzymes GPI, LAP and SDH. In at least one unequivocal case it could be proved for each enzyme system studied that the alleles of both parents arc independently expressed in the newly synthesized individuals and that in the pattern of the dimeric enzyme GPI interlocus bands of the homoeologous loci arc visible. Comparisons with enzyme patterns in cultivated B. napus leads to the conclusion that in general active enzyme loci of both parental genomes are present. This is of great significance in estimating slide frequencies, degree of heterozygosity and other genetic parameters of B. nupus populations/cultivars.  相似文献   

Weighing in on a method to discriminate maize haploid from hybrid seed          下载免费PDF全文

Andrew Smelser  Michael Blanco  Thomas Lübberstedt  Axel Schechert  Adam Vanous  Candice Gardner 《Plant Breeding》2015,134(3):283-285

The doubled haploid breeding method can produce maize inbred lines faster than traditional methods, but there are challenges associated with it. Sorting haploid from hybrid seed based on visual colour markers is time consuming and can be difficult due to colour inhibitors that obscure pigmentation needed to distinguish between haploid, hybrid and outcrossed seed. In this study, weight was evaluated as a method to sort haploid from hybrid seed. A first experiment utilized two families for analysis in a preliminary study. Eleven haploid and hybrid kernels from both families were weighed for a total of 44 experimental units. A second experiment was carried out using six families, using the same format as the previous, for 132 experimental units. Hybrid seed weighed significantly more than haploid seed in both experiments. However, the interaction between line and kernel type was significant in the second experiment. In conclusion, efficacy of sorting haploid from hybrid kernels based on weight depends on the genotypes involved.  相似文献   

The effect of GnRH on the pregnancy ratio in low-yielding local race cows: comparison of different injection times     

Uslu  Barış Atalay  Kocyigit  Alper  Sendag  Sait  Gülyüz  Fetih  Wehrend  Axel 《Tropical animal health and production》2020,52(2):497-502

Tropical Animal Health and Production - The objective of this article was to investigate the efficiency of GnRH administrations at different time points after induced luteolysis on pregnancy rates...  相似文献   

The phosphorus status of German cropland—An inventory of top‐ and subsoils     

Martina I. Gocke  Axel Don  Arne Heidkamp  Florian Schneider  Wulf Amelung 《植物养料与土壤学杂志》2021,184(1):51-64

Background : In search for more sustainable crop production, the subsoil has recently come into focus as considerable reservoir of nutrients and water. Aims : Dimensions of subsoil phosphorus (P) reserves are yet largely unknown but crucial for identifying regions suitable to include subsoil into sustainable management strategies. Methods : We analyzed stocks of total and plant‐available (calcium acetate lactate‐extractable) P in 96 representative soil profiles of German arable land down to 1 m depth. Results : We found that the German arable soils stored, on average, 8 t ha^?1 of total P, of which nearly 500 kg ha^?1 were readily plant‐available. Notably, one third of plant‐available P was located below the plow layer and one fifth even at depths below 0.5 m. The depth gradients of plant‐available P stocks were affected more by major reference soil group than by texture. Generally, Chernozem but also Anthrosol, Gleysol and Fluvisol exhibited the largest P stocks in German cropland. The contribution of plant‐available P to total P stocks was larger in sandy and extremely acidic (pH < 4.5) soils compared with more fine‐grained and slightly acidic to alkaline soils, possibly because fertilization compensated for overall lower total P stocks at these sites. Generally, the more P was stored in topsoils, the more P was stored also in subsoils. Conclusions : A hypothetical crop utilization of 10% from plant‐available P stocks and 0.1% from total P stocks from shallow subsoil could compensate for P fertilization by ca. 8 kg ha^?1, but the rate of plant‐available P replenishment in subsoil likely remains the crucial factor for the role of subsoil P stocks in crop nutrition. Generally, the large P reserves found in subsoil could act as an ‘insurance' system for crops.  相似文献