Root growth and thickening plays a key role in the final productivity and even the quality of storage roots in root crops. This study was conducted to identify and map quantitative trait loci (QTLs) affecting root morphological traits in Brassica rapa by using molecular markers. An F2 population was developed from a cross between Chinese cabbage (Brassica rapa ssp. chinensis) and turnip (B. rapa ssp. rapifera), which differed greatly in root characters. A genetic map covering 1837.1 cM, with 192 marker loci and 11 linkage groups, was constructed by using this F2 population. The F3 families derived from F2 plants were grown in the field and evaluated for taproot traits (thickness, length, and weight). QTL analysis via simple interval mapping detected 18 QTLs for the 3 root traits, including 7 QTLs for taproot thickness, 5 QTLs for taproot length, and 6 QTLs for taproot weight. Individually, the QTLs accounted for 8.4?27.4% of the phenotypic variation. The 2 major QTLs, qTRT4b for taproot thickness and qTRW4 for taproot weight, explained 27.4% and 24.8% of the total phenotypic variance, respectively. The QTLs for root traits, firstly detected in Brassica crops, may provide a basis for marker-assisted selection to improve productivity in root-crop breeding.
Status epilepticus (SE) is a grave condition in which the brain undergoes lasting seizures which can lead to neuronal loss. Our previous study suggested that preconditioning with erythropoietin (Epo) suppressed neuronal apoptosis in hippocampus of rats following SE in vivo by inhibiting caspase-3. In this study, we investigated the mechanisms by which Epo preconditioning may exert its anti-apoptotic effects using a lithium-pilocarpine induced SE model in rats. The effects of Epo on neuronal cell death were evaluated using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), and the role of the Bcl-2 protein family, which have been shown to be anti- (Bcl-2, Bcl-w) or pro- (Bid, Bim) apoptotic, was examined with immunofluorescence. We found Epo preconditioning decreased the total number of TUNEL, Bim and Bid positive cells, but increased the total number of Bcl-w and Bcl-2 positive cells. These results suggest that systemic Epo pretreatment protects neurons in an acute phase of SE and may result in further suppression of neuronal apoptosis in hippocampus by regulating the balance between pro- and anti-apoptotic Bcl-2 family proteins.