Most agricultural traits are controlled by quantitative trait loci (QTLs); however, there are few studies on QTL mapping of horticultural traits in pepper (Capsicum spp.) due to the lack of high-density molecular maps and the sequence information. In this study, an ultra-high-density map and 120 recombinant inbred lines (RILs) derived from a cross between C. annuum ‘Perennial’ and C. annuum ‘Dempsey’ were used for QTL mapping of horticultural traits. Parental lines and RILs were resequenced at 18× and 1× coverage, respectively. Using a sliding window approach, an ultra-high-density bin map containing 2,578 bins was constructed. The total map length of the map was 1,372 cM, and the average interval between bins was 0.53 cM. A total of 86 significant QTLs controlling 17 horticultural traits were detected. Among these, 32 QTLs controlling 13 traits were major QTLs. Our research shows that the construction of bin maps using low-coverage sequence is a powerful method for QTL mapping, and that the short intervals between bins are helpful for fine-mapping of QTLs. Furthermore, bin maps can be used to improve the quality of reference genomes by elucidating the genetic order of unordered regions and anchoring unassigned scaffolds to linkage groups.

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Cucumber mosaic virus (CMV) is one of the most destructive viruses in the Solanaceae family. Simple inheritance of CMV resistance in peppers has not previously been documented; all previous studies have reported that resistance to this virus is mediated by several partially dominant and recessive genes. In this study, we showed that the Capsicum annuum cultivar 'Bukang' contains a single dominant resistance gene against CMV(Korean) and CMV(FNY) strains. We named this resistance gene Cmr1 (Cucumber mosaic resistance 1). Analysis of the cellular localization of CMV using a CMV green fluorescent protein construct showed that in 'Bukang,' systemic movement of the virus from the epidermal cell layer to mesophyll cells is inhibited. Genetic mapping and FISH analysis revealed that the Cmr1 gene is located at the centromeric region of LG2, a position syntenic to the ToMV resistance locus (Tm-1) in tomatoes. Three SNP markers were developed by comparative genetic mapping: one intron-based marker using a pepper homolog of Tm-1, and two SNP markers using tomato and pepper BAC sequences mapped near Cmr1. We expect that the SNP markers developed in this study will be useful for developing CMV-resistant cultivars and for fine mapping the Cmr1 gene.

Recent studies have demonstrated the protective effect of mitochondrial aldehyde dehydrogenase 2 (ALDH2) in cardiovascular diseases. Increased levels of the potential ALDH2 substrate 4-hydroxynonenal (4-HNE) are involved in myocardial/cerebral ischemia accompanied by a high level of oxidative stress. In this investigation, we first performed a case-control study to explore the potential association of ALDH2 rs671 polymorphism and post-stroke epilepsy (PSE). Then, we performed an in vitro study to determine whether the overexpression of ALDH2 could decrease the level of oxidative stress and the apoptosis ratio induced by 4-HNE. There was a significant difference in the distribution of the allele and genotype frequencies of the rs671 polymorphism between PSE patients and ischemic stroke (IS) patients. Individuals with the rs671 A allele showed significantly higher levels of plasma 4-HNE. The overexpression of ALDH2 partially blocked the increased levels of malondialdehyde (MDA), reactive oxygen species (ROS) and apoptosis ratio induced by 4-HNE and also partially restored the ALDH2 activity in PC12 cells; these effects were reversed in the presence of εV1-2. Our results suggest that the ALDH2 rs671 polymorphism is associated with PSE susceptibility and affects the 4-HNE levels. Targeting ALDH2 might be a useful strategy for the treatment or prevention of PSE.