ABSTRACT
Wheat cultivar Shaannong 33 (SN33) has remained highly resistant to stripe rust in the field since its release in 2009. To unravel the genetic architecture of stripe rust resistance, seedlings of 161 recombinant inbred lines (RILs) from the cross Avocet S × SN33 were evaluated with two isolates (PST-Lab.1 and PST-Lab.2) of the stripe rust pathogen (Puccinia striiformis f. sp. tritici) in the greenhouse, and the RILs were evaluated in naturally or artificially inoculated field sites during two cropping seasons. The RILs and parents were genotyped with the wheat 55K single-nucleotide polymorphism array. Three genomic regions conferring seedling resistance were mapped on chromosomes 1DS, 2AS, and 3DS, and four consistent quantitative trait loci (QTL) for adult-plant resistance (APR) were detected on 1BL, 2AS, 3DL, and 6BS. The 2AS locus conferring all-stage resistance was identified as the resistant gene Yr17 located on 2NS translocation. The QTL identified on 1BL and 6BS likely correspond to Yr29 and Yr78, respectively. An APR QTL on 3DL explaining 5.8 to 12.2% of the phenotypic variation is likely to be new. Molecular marker detection assays with the 2NS segment (Yr17), Yr29, Yr78, and QYrsn.nwafu-3DL on a panel of 420 current Chinese wheat cultivars and breeding lines indicated that these genes were present in 11.4, 7.6, 14.8, and 7.4% of entries, respectively. The interactions among these genes and QTL were additive, suggesting their potential value in enhancing stripe rust resistance breeding materials as observed in the resistant parent. In addition, we also identified two leaf necrosis genes, Ne1 and Ne2; however, the F1 plants from cross Avocet S × SN33 survived, indicating that SN33 probably has another allele of Ne1 which allows seed to be harvested.
Subject(s)
Disease Resistance , Triticum , Alleles , China , Disease Resistance/genetics , Humans , Plant Breeding , Plant Diseases/genetics , Triticum/geneticsABSTRACT
Cancer stem cells (CSCs) have been reported to be associated with the recurrence and drug resistance of liver cancer. In the present study, stem celllike HepG2 cell spheres were enriched using stem cell conditioned culture medium. As expected, stemlike HepG2 cell spheres exhibited increased resistance to sorafenib. Metformin, a common drug used to treat type 2 diabetes mellitus, reduced the diameters and numbers of stemlike HepG2 spheres, and increased their sensitivity to sorafenib. Western blotting confirmed that low doses of metformin reversed the epithelialmesenchymal transformation (EMT) process of HepG2 spheres. These results suggested that metformin enhanced sensitivity to sorafenib, which was probably through reversal of the EMT process of sphereforming cells and by reducing the formation of CSCs.