ABSTRACT
Using ultra high performance liquid chromatography (UHPLC) coupled with mass spectrum (MS) technology, a method has been established for separation and analysis of alkaloid isomers. Alkaloids in Ephedra sinica transitionally crossed blood brain barrier (BBB) and the distribution were investigated. The concentrations of Ephedra alkaloids in rat central nervous system (CNS) were determined to acquire the distribution characteristics and differences in cerebral cortex, cerebellum, hippocampus, striatum, medulla oblongata and hypothalamus. It was founded that pseudoephedrine, norephedrine, norpseudoephedrine, methylephedrine (methylpseudoephedrine) were able to cross BBB fast via gastro-intestinal tract after administrated with Ephedra sinica. Cortex and hippocampus was the main distribution region, followed by hypothalamus, striatum and cerebellum, in which medulla oblongata had the least. The distribution of various alkaloids, as AUC0-t, brain/AUC0-t, blood was ephedrine > methylephedrine > demethyl ephedrine. Alkaloids in Ephedra sinica crossed BBB rapidly, showing the regional distribution tendency in central nervous system, and the distribution was diversity. This group of data provides distribution of bioactive constituents of Ephedra in CNS.
ABSTRACT
G46B is a promising holding line used for three-lines breeding strategy in hybrid rice, but it is susceptible to blast disease caused by Pyricularia grisea. To improve its blast resistance, three rice varieties, Digu, BL-1, and Pi-4, with blast resistance genes, Pi-d(t), Pi-b, and Pi-ta2, respectively, were used to be crossed with G46B, and 15 plants with these three blast resistance genes, Pi-d(t)1, Pi-b, and Pi-ta2, were selected from their F2 and B1C1 populations via a marker-aided crossing procedure. Among them, four plants were heterozygotes in the three resistance genes, with the genotype of Pi-d(t)1 pi-d(t)/Pi-b pi-b/ Pi-ta2 pi-ta2; ten plants were heterozygotes in two of the three resistance genes, of which six with the genotype of Pi-d(t)1 Pi-d(t)1/Pi-b pi-b/Pi-ta2 pi-ta2, three with the genotype of Pi-d(t)1 pi-d(t)1/Pi-b pi-b/Pi-ta2 Pi-ta2, and one with the genotype of Pi-d(t)1pi-d(t)1/Pi-b Pi-b/Pi-ta2 pi-ta2; and only one plant was homozygote in two of the three resistance genes with the genotype of Pi-d(t)1 Pi-d(t)/Pi-b pi-b/Pi-ta2 Pi-ta2. These results demonstrate the capacity of maker-assisted selection (MAS) in gene pyramiding for rice blast resistance and its enhancement for the efficiency in rice resistance breeding.
Subject(s)
Crosses, Genetic , Genes, Plant , Genetic Markers , Genotype , Oryza , Genetics , Plant Diseases , Genetics , Selection, GeneticABSTRACT
'Shuhui527' is a promising restorer line bred by Rice Research Institute of Sichuan Agricultural University in recent years. However, this line is susceptible to Bacterial Blight (BB), which limits its use. The IRBB60, from the International Rice Research Institute (IRRI), contains dominant genes Xa21 and Xa4 conferring resistance to BB. The objective of this study is to improve the BB resistance of 'Shuhui527' by introgressing Xa21 and Xa4, the two broad-spectrum BB resistance genes, into 'Shuhui527' with IRBB60 as the donor, pTA248 and MP12, linking tightly with Xa21 and Xa4 respectively as DNA markers. BC1 F1 progenies of (Shuhui527 x IRBB60), containing Xa21 and Xa4 identified using PCR screening and with agronomic traits including plant type, grain type and days to heading etc similar to those of 'Shuhui527', were subsequently backcrossed to 'Shuhui527' and self-pollinated to generate BC2 F1 and BC1 F2 . The BC3 F1 and BC3 F2 were subsequently developed using the same approach. Among the 20 BC3 F2 plants, homozygous Xa21 and Xa4,10 plants were the most similar to 'Shuhui527' in the agronomic traits, and were screened using 120 pairs SSR and 100 pairs RAPD markers. Based on the results of the background screening and the performance of the agronomic traits, 5 plants were identified as improved-'Shuhui527' and designated as 527R-5, 527R-6, 527R-8, 527R-9 and 527R-10. The improved-' Shuhui527' lines expressed high resistance to Xanthomonas oryzae pv . oryzae (Xoo) stains C I - C VII, P1 and P6. The evaluation of the polymorphisms and selection accuracies of pTA248 and MP12 demonstrated that the polymorphisms of the two markers were obvious and co-dominant and the accuracies were more than 97% and 83% respectively, indicating the two markers are good for Xa21 and Xa4 in Molecular Marker-assisted Selection.