Genetic Fine-Mapping and Identification of Candidate Genes and Variants for Adiposity Traits in Outbred Rats

OBJECTIVE: Obesity is a major risk factor for multiple diseases and is in part heritable, yet the majority of causative genetic variants that drive excessive adiposity remain unknown. Here, outbred heterogeneous stock (HS) rats were used in controlled environmental conditions to fine‐map novel genetic modifiers of adiposity. METHODS: Body weight and visceral fat pad weights were measured in male HS rats that were also genotyped genome‐wide. Quantitative trait loci (QTL) were identified by genome‐wide association of imputed single‐nucleotide polymorphism (SNP) genotypes using a linear mixed effect model that accounts for unequal relatedness between the HS rats. Candidate genes were assessed by protein modeling and mediation analysis of expression for coding and noncoding variants, respectively. RESULTS: HS rats exhibited large variation in adiposity traits, which were highly heritable and correlated with metabolic health. Fine‐mapping of fat pad weight and body weight revealed three QTL and prioritized five candidate genes. Fat pad weight was associated with missense SNPs in Adcy3 and Prlhr and altered expression of Krtcap3 and Slc30a3, whereas Grid2 was identified as a candidate within the body weight locus. CONCLUSIONS: These data demonstrate the power of HS rats for identification of known and novel heritable mediators of obesity traits

Phosphorus efficiency for symbiotic N2 fixation of common bean <em>(Phaseolus vulgaris</em>) is affected by the form of phosphorus application in hydroaeroponic culture

International audiencePhosphorus uptake and utilisation by common beans (Phaseolus vulgaris) is essential for proper growth, and ensuring high yield and improved quality of the crop. To study the effects of the phosphorus application forms on the phosphorus use efficiency (PUE), for symbiotic nitrogen fixation (SNF), six common bean recombinant inbred lines (RIL) from the cross of BAT477 × DOR364 were inoculated by Rhizobium tropici CIAT 899, and submitted to five organic and inorganic treatments of P in hydroaeroponic culture in glasshouse in the south of France. The results showed significant differences in shoot and nodule biomass among inorganic and organic P sources with all RILs studied. In particular a significant increase was observed in shoot P content with bochevo and apatite compared to phytate and glycero P whereas RILs 83, 75 and 147 registered as a higher P uptake. A greater PUE was observed for RILs 34, 75 and 115 than other RILs with organic P especially under 75P (deficient P). A significant release of H+ was observed with organic P supply whereas bochevo buffered the pH which was suitable for nodulation and plant growth. In conclusion, the organic P forms could contribute to P uptake by nodulated common bean. Whereas bochevo was the most efficient source of P because of its positive effect on pH in hydroaeroponic culture