Top Grafting Longleaf x Slash Pine F1 Hybrids on Mature Longleaf and Slash Pine Interstocks

Top grafting is used to accelerate the breeding cycle of loblolly pine (Pinus taeda L). Scions, collected from seedlings as young as 1 year from seed, are grafted onto mature interstocks of the same or a related species. Male and female strobili production often begins 1 or 2 years after grafting, thus potentially decreasing the generation time by several years over conventional accelerated breeding methods. We are interested in applying top grafting to our breeding program involving interspecific hybrids, in particular longleaf x slash pine (Pinus palustris Mill. x Pinus elliottii Englem. var. elliottii) hybrids and their backcross generations. Towards this end, we grafted scions from 16 longleaf x slash pine F1 selections onto two longleaf and two slash pine interstock trees of different genotype. The F1 selections were 6 years old and none showed any signs of strobili development prior to, or during the experiment. A total of 100 grafts were made on to each interstock species. Scion survival after the second year was significantly higher on slash (72%) pine interstocks than on longleaf pine (18%). However there were no differences in male or female strobili production per living scion between the interstock species. Scions grew longer and produced more branches on slash pine interstocks than they did on longleaf. Given the relatively poor survival of the scions grafted onto longleaf interstocks and the reasonably good strobili production of scions grafted onto slash, we recommend using slash pine as the interstock species for top grafting longleaf x slash F1 hybrids.Papers and abstracts from the 27th Southern Forest Tree Improvement Conference held at Oklahoma State University in Stillwater, Oklahoma on June 24-27, 2003

Temporal relationship between systemic endothelial dysfunction and alterations in erythrocyte function in a murine model of chronic heart failure

Endothelial dysfunction (ED) and red blood cell distribution width (RDW) are both prognostic factors in heart failure (HF), but the relationship between them is not clear. In this study, we used a unique mouse model of chronic HF driven by cardiomyocyte-specific overexpression of activated Gαq protein (Tgαq*44 mice) to characterise the relationship between the development of peripheral ED and the occurrence of structural nanomechanical and biochemical changes in red blood cells (RBCs).Systemic ED was detected in vivo in 8-month-old Tgαq*44 mice, as evidenced by impaired acetylcholine-induced vasodilation in the aorta and increased endothelial permeability in the brachiocephalic artery. ED in the aorta was associated with impaired nitric oxide (NO) production in the aorta and diminished systemic NO bioavailability. ED in the aorta was also characterised by increased superoxide and eicosanoid production. In 4- to 6-month-old Tgαq*44 mice, RBC size and membrane composition displayed alterations that did not result in significant changes in their nanomechanical and functional properties. However, 8-month-old Tgαq*44 mice presented greatly accentuated structural and size changes and increased RBC stiffness. In 12-month-old Tgαq*44 mice, the erythropathy was featured by severely altered RBC shape and elasticity, increased RDW, impaired RBC deformability, and increased oxidative stress (GSH/GSSH ratio). Moreover, RBCs taken from 12-month-old Tgαq*44 mice, but not from 12-month-old FVB mice, co-incubated with aortic rings from FVB mice, induced impaired endothelium-dependent vasodilation and this effect was partially reversed by an arginase inhibitor (ABH, 2(S)-amino-6-boronohexanoic acid).In the Tgαq*44 murine model of HF, systemic endothelial dysfunction accelerates erythropathy and, conversely, erythropathy may contribute to endothelial dysfunction. These results suggest that erythropathy may be regarded as a marker and a mediator of systemic endothelial dysfunction in HF. In particular, targeting RBC arginase may represent a novel treatment strategy for systemic endothelial dysfunction in HF. RBC arginase and possibly other RBC-mediated mechanisms may represent novel therapeutic targets for systemic endothelial dysfunction in HF.Endothelial dysfunction (ED) and red blood cell distribution width (RDW) both have prognostic value for heart failure (HF), but it is not known whether these pathologies are related. We comprehensively characterized endothelial and RBC functional status in a unique murine model of chronic heart failure with a prolonged time course of HF progression. Our results suggest that ED accelerates erythropathy and, conversely, erythropathy may contribute to ED. Accordingly, erythropathy in HF reflects ED and involves various changes (in functional, structural, nanomechanical, and biochemical levels) that could have diagnostic and therapeutic significance for HF

Finding Single Copy Genes Out of Sequenced Genomes for Multilocus Phylogenetics in Non-Model Fungi

Historically, fungal multigene phylogenies have been reconstructed based on a small number of commonly used genes. The availability of complete fungal genomes has given rise to a new wave of model organisms that provide large number of genes potentially useful for building robust gene genealogies. Unfortunately, cross-utilization of these resources to study phylogenetic relationships in the vast majority of non-model fungi (i.e. “orphan” species) remains an unexamined question. To address this problem, we developed a method coupled with a program named “PHYLORPH” (PHYLogenetic markers for ORPHans). The method screens fungal genomic databases (107 fungal genomes fully sequenced) for single copy genes that might be easily transferable and well suited for studies at low taxonomic levels (for example, in species complexes) in non-model fungal species. To maximize the chance to target genes with informative regions, PHYLORPH displays a graphical evaluation system based on the estimation of nucleotide divergence relative to substitution type. The usefulness of this approach was tested by developing markers in four non-model groups of fungal pathogens. For each pathogen considered, 7 to 40% of the 10–15 best candidate genes proposed by PHYLORPH yielded sequencing success. Levels of polymorphism of these genes were compared with those obtained for some genes traditionally used to build fungal phylogenies (e.g. nuclear rDNA, β-tubulin, γ-actin, Elongation factor EF-1α). These genes were ranked among the best-performing ones and resolved accurately taxa relationships in each of the four non-model groups of fungi considered. We envision that PHYLORPH will constitute a useful tool for obtaining new and accurate phylogenetic markers to resolve relationships between closely related non-model fungal species

Evolution of Genome Size and Complexity in Pinus

BACKGROUND: Genome evolution in the gymnosperm lineage of seed plants has given rise to many of the most complex and largest plant genomes, however the elements involved are poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: Gymny is a previously undescribed retrotransposon family in Pinus that is related to Athila elements in Arabidopsis. Gymny elements are dispersed throughout the modern Pinus genome and occupy a physical space at least the size of the Arabidopsis thaliana genome. In contrast to previously described retroelements in Pinus, the Gymny family was amplified or introduced after the divergence of pine and spruce (Picea). If retrotransposon expansions are responsible for genome size differences within the Pinaceae, as they are in angiosperms, then they have yet to be identified. In contrast, molecular divergence of Gymny retrotransposons together with other families of retrotransposons can account for the large genome complexity of pines along with protein-coding genic DNA, as revealed by massively parallel DNA sequence analysis of Cot fractionated genomic DNA. CONCLUSIONS/SIGNIFICANCE: Most of the enormous genome complexity of pines can be explained by divergence of retrotransposons, however the elements responsible for genome size variation are yet to be identified. Genomic resources for Pinus including those reported here should assist in further defining whether and how the roles of retrotransposons differ in the evolution of angiosperm and gymnosperm genomes