Development and Validation of Molecular Markers for \u3cem\u3ePhytophthora medicaginis\u3c/em\u3e Resistance in Lucerne

Resistance to Phytophthora medicaginis is an essential attribute to incorporate into lucerne (Medicago sativa) cultivars which are likely to be grown on heavy soils or in conditions where the soil remains excessively wet for prolonged periods. Current breeding strategies rely on recurrent phenotypic selection to maintain adequate levels of resistance in newly developed synthetic cultivars. However, little is known about the source or mechanism(s) of genetic resistance operating in the cultivar. A genetic linkage map was generated from a tetraploid M. sativa population using SSR markers anchored to existing genetic and physical maps. Large effect QTL were identified on linkage groups 2, 5, 6 and 7, each of which contributed between 11-30% of the phenotypic variation. Evaluation of the marker-trait associations in another sampling of the same population was undertaken, using a different isolate of P. medicaginis. The findings indicate that in the lucerne genotype examined in this study, a network of interactions involving at least three common loci, contribute to resistance to P. medicaginis. An alignment of the resistance loci identified in this study with those previously identified provided a framework for cataloguing the diversity of resistance loci present in lucerne, and will be used to guide future lucerne breeding efforts

Identification of molecular markers of delayed graft function based on the regulation of biological ageing

Introduction: Delayed graft function is a prevalent clinical problem in renal transplantation for which there is no objective system to predict occurrence in advance. It can result in a significant increase in the necessity for hospitalisation post-transplant and is a significant risk factor for other post-transplant complications. Methodology: The importance of microRNAs (miRNAs), a specific subclass of small RNA, have been clearly demonstrated to influence many pathways in health and disease. To investigate the influence of miRNAs on renal allograft performance post-transplant, the expression of a panel of miRNAs in pre-transplant renal biopsies was measured using qPCR. Expression was then related to clinical parameters and outcomes in two independent renal transplant cohorts. Results: Here we demonstrate, in two independent cohorts of pre-implantation human renal allograft biopsies, that a novel pre-transplant renal performance scoring system (GRPSS), can determine the occurrence of DGF with a high sensitivity (>90%) and specificity (>60%) for donor allografts pre-transplant, using just three senescence associated microRNAs combined with donor age and type of organ donation. Conclusion: These results demonstrate a relationship between pre-transplant microRNA expression levels, cellular biological ageing pathways and clinical outcomes for renal transplantation. They provide for a simple, rapid quantitative molecular pre-transplant assay to determine post-transplant allograft function and scope for future intervention. Furthermore, these results demonstrate the involvement of senescence pathways in ischaemic injury during the organ transplantation process and an indication of accelerated bio-ageing as a consequence of both warm and cold ischaemia

The expression of ovine placental lactogen, StAR and progesterone-associated steroidogenic enzymes in placentae of overnourished growing adolescent ewes.

Overnourishing pregnant adolescent sheep promotes maternal growth but reduces placental mass, lamb birth weight and circulating progesterone. This study aimed to determine whether altered progesterone reflected transcript abundance for StAR (cholesterol transporter) and the steroidogenic enzymes (Cyp11A1, Hsd3b and Cyp17). Circulating and placental expression of ovine placental lactogen (oPL) was also investigated. Adolescent ewes with singleton pregnancies were fed high (H) or moderate (M) nutrient intake diets to restrict or support placental growth. Experiment 1: peripheral progesterone and oPL concentrations were measured in H (n=7) and M (n=6) animals across gestation (days 7-140). Experiment 2: progesterone was measured to mid- (day 81; M: n=11, H: n=13) or late gestation (day 130; M: n=21, H: n=22), placental oPL, StAR and steroidogenic enzymes were measured by qPCR and oPL protein by immunohistochemistry. Experiment 1: in H vs M animals, term placental (