Swedish University of Agricultural Sciences

About: Swedish University of Agricultural Sciences is a education organization based out in Uppsala, Sweden. It is known for research contribution in the topics: Population & Soil water. The organization has 13510 authors who have published 35241 publications receiving 1414458 citations. The organization is also known as: Sveriges Lantbruksuniversitet & SLU.

Rabbit genome analysis reveals a polygenic basis for phenotypic change during domestication.

Abstract: The genetic changes underlying the initial steps of animal domestication are still poorly understood. We generated a high-quality reference genome for the rabbit and compared it to resequencing data from populations of wild and domestic rabbits. We identified more than 100 selective sweeps specific to domestic rabbits but only a relatively small number of fixed (or nearly fixed) single-nucleotide polymorphisms (SNPs) for derived alleles. SNPs with marked allele frequency differences between wild and domestic rabbits were enriched for conserved noncoding sites. Enrichment analyses suggest that genes affecting brain and neuronal development have often been targeted during domestication. We propose that because of a truly complex genetic background, tame behavior in rabbits and other domestic animals evolved by shifts in allele frequencies at many loci, rather than by critical changes at only a few domestication loci.

Interacting signal pathways control defense gene expression in Arabidopsis in response to cell wall-degrading enzymes from Erwinia carotovora.

Abstract: We have characterized the role of salicylic acid (SA)-independent defense signaling in Arabidopsis thaliana in response to the plant pathogen Erwinia carotovora subsp. carotovora. Use of pathway-specific target genes as well as signal mutants allowed us to elucidate the role and interactions of ethylene, jasmonic acid (JA), and SA signal pathways in this response. Gene expression studies suggest a central role for both ethylene and JA pathways in the regulation of defense gene expression triggered by the pathogen or by plant cell wall-degrading enzymes (CF) secreted by the pathogen. Our results suggest that ethylene and JA act in concert in this regulation. In addition, CF triggers another, strictly JA-mediated response inhibited by ethylene and SA. SA does not appear to have a major role in activating defense gene expression in response to CF. However, SA may have a dual role in controlling CF-induced gene expression, by enhancing the expression of genes synergistically induced by ethylene and JA and repressing genes induced by JA alone.

Responses of n‐limited ecosystems to increased co2: a balanced‐nutrition, coupled‐element‐cycles model

Abstract: Ecosystem responses to increased CO2 are often constrained by nutrient limitation. We present a model of multiple-element limitation (MEL) and use it to analyze constraints imposed by N on the responses to an instantaneous doubling of CO2 concen- tration in a 350-yr-old eastern deciduous forest. We examine the effects of different exchange rates of inorganic N with sources and sinks external to the ecosystem (e.g., through de- position and leaching) and different initial ratios of net: gross N mineralization. Both of these factors influence the availability of N to vegetation and, therefore, have important effects on ecosystem responses to increased CO2. We conclude that reliable assessments of ecosystem responses to CO2 will require a better understanding of both these factors. The responses to increased CO2 appear on at least four characteristic time scales. (1) There is an instantaneous increase in net primary production, which results in an increase in the vegetation C:N ratio. (2) On a time scale of a few years, the vegetation responds by increasing uptake effort for available N (e.g., through increased allocation of biomass, energy, and enzymes to fine roots). (3) On a time scale of decades, there is a net movement of N from soil organic matter to vegetation, which enables vegetation biomass to accumulate. (4) On the time scale of centuries, ecosystem responses are dominated by increases in total ecosystem N, which enable organic matter to accumulate in both vegetation and soils. In general, short-term responses are markedly different from long-term responses.

Cell Cycle Progression in the Pericycle Is Not Sufficient for SOLITARY ROOT/IAA14-Mediated Lateral Root Initiation in Arabidopsis thaliana

Abstract: To study the mechanisms behind auxin-induced cell division, lateral root initiation was used as a model system. By means of microarray analysis, genome-wide transcriptional changes were monitored during the early steps of lateral root initiation. Inclusion of the dominant auxin signaling mutant solitary root1 (slr1) identified genes involved in lateral root initiation that act downstream of the auxin/indole-3-acetic acid (AUX/IAA) signaling pathway. Interestingly, key components of the cell cycle machinery were strongly defective in slr1, suggesting a direct link between AUX/IAA signaling and core cell cycle regulation. However, induction of the cell cycle in the mutant background by overexpression of the D-type cyclin (CYCD3;1) was able to trigger complete rounds of cell division in the pericycle that did not result in lateral root formation. Therefore, lateral root initiation can only take place when cell cycle activation is accompanied by cell fate respecification of pericycle cells. The microarray data also yielded evidence for the existence of both negative and positive feedback mechanisms that regulate auxin homeostasis and signal transduction in the pericycle, thereby fine-tuning the process of lateral root initiation.