Brassica rapa is one of the most valuable vegetable crops worldwide. Cultivated varieties of B. rapa exhibit diverse developmental and morphological appearances, which includes important vegetables, oilseeds, and fodder crops. In this study, various phenotypes of recombinant inbred lines (RILs) of B. rapa were investigated, including their responses to five different pathogenic Botrytis cinerea isolates, responses to aphid and thrips during flowering stages, days to flowering, and plant heights. Responses of 113 RILs to five different B. cinerea isolates showed variations, suggesting that genetic factors controlling resistance or tolerance against each isolate were dependent on isolate/genotype pairs. Correlation analysis was performed to understand the nature of genetic factors and the relationship among these phenotypes. Although high levels of correlation were not detected between phenotypes assessed in this study, statistically significant correlation was detected for several combinations. Significant positive correlations were found for different B. cinerea isolates, supporting that certain levels of commonality could exist in genetic components controlling resistance against different B. cinerea isolates. Based on correlation analysis using numbers of insects counted on plants, it was speculated that genetic factors responsible for aphid tolerance or repellence might be also involved in the response against thrips. Relationship between vegetative growth and tolerance against B. cinereal or insects is rather more complicated. However, it was observed that shorter plants appeared to have a certain level of tolerance or repellence against both aphids and thrips. Data presented in this study could be used to assist further genetic studies and breeding efforts to obtain Botritis and insect resistance for B. rapa.

Balloon flower (Platycodon grandiflorum A. DC.) is a perennial plant of mainly Campanulaceae family, which have been widely used as a food ingredient and herbal medicine in East Asia. Although demands on related products and yearly cultivation area for balloon flower are increasing, diverse fundamental technologies and molecular breeding studies are not very well supported in Platycodons. In this study, 30 random amplification of polymorphic DNA (RAPD) primers were test in an attempt to explore genetic diversities. In addition, sequences information of the actin gene, a well conserved gene encoding a globular protein that forms microfilaments, was retrieved and analyzed. Two actin homologs were recovered; 3.4 kb fragment is a Pg-actin and 1.4 kb fragment is a Pg-actin homolog with 28.6% similarity. We have confirmed that the Pg-actin gene is configured into 4 exons and 3 introns. A single nucleotide polymorphism (SNP), G↔A, was detected on the intron 3, which served as a target for the CAPS marker development. The marker Pg-Actin-Int3 was applied to 32 balloon flower accessions. Balloon flower DNA sequence information generated in this study is expected to contribute to the analysis and molecular breeding and genetic diversity analysis of balloon flowers.

Marker assisted selection (MAS) for disease resistance is widely applied in practical tomato breeding program both in public and private sectors. Due to the commercial value and the importance as a model crop system, tomato has taken the lead in MAS among the other horticultural crops. A wide range of disease resistance genes were identified and the mechanism of the resistances has been explored in tomatoes. In the case of disease resistance Tomato yellow leaf curl virus (TYLCV) is one of the major threats for tomato production worldwide, and several resistance sources for TYLCV resistance have been identified among wild tomato species. Ty1/3 resistance gene has been recently identified as a DFDGD-class RNA dependent RNA polymerase (RDR). Late blight (LB) in tomato is caused by Phythophthora infestans, and several resistances sources have been applied in the practical breeding program. Ph3 resistance, a LB resistance against a wide-range of P. infestans isolates, has been reported as a gene coding a CC-NBS-LRR gene on chromosome 9. In this study, we developed reliable and comprehensive molecular markers based on the single nucleotide polymorphisms (SNPs) or insertion/deletion (InDel) directly responsible for the resistance phenotype. These functional molecular markers are expected to enhance the effectivity and accuracy of MAS for disease resistance in tomato breeding programs.

Tomato fruit color, which is the most visible characteristic among the other fruit traits, is considered to have a substantial influence on consumers. The pink-colored tomatoes with high soluble solids content are considerably preferred especially in Asia compared to the other colors. Generally the pink fruit trait of tomatoes is easily determined by visual examination of intact fruit, however, it is technically determined by the characteristic of the fruit peel. The pink trait is regulated by variations of the SlMYB12(y) gene located on chromosome 1, which controls the accumulation of the naringenin chalcone, which comprises a large proportion of flavonoids. In this study, we developed a derived Cleaved Amplified Polymorphic Sequences (dCAPS) marker and a sequence characterized amplified regions (SCAR) marker in order to discriminate of pink/non-pinktomatoes in the domestic breeding lines. Quantitative RT-PCR analysis indicated that the SlMYB gene is highly expressed in non-pink fruit peel, whereas the expression is significantly lowered in the pink fruit peel. These gene based markers are expected to enhance the efficiency and accuracy of selection pink-tomatoes in tomato breeding programs.

Platycodon grandiflorum, which is the only species in the genus Platycodon of the family Campanulaceae, is an herbaceous flowering perennial. P. grandiflorum is generally known as bellflower or balloon flower indicating its ornamental uses. It has also been traditionally used as a medicinal crop in East Asia, which is widely employed as an antiphlogistic, antitussive, and expectorant. However, marker-assisted selection and molecular breeding in P. grandiflorum has lagged behind other plants such as pepper and tomato because of the lack of genetic information and effective molecular markers. Transcriptome sequencing provides an effective way to obtain large amount of sequence data when there is no available genome sequence. In this study, we performed a transcriptome analysis in platycodons, which has not been attempted previously. We analyzed simple sequence repeats (SSRs) using RNA-seq data. Di-nucleotide motifs were the most abundant repeats (39% ~ 40%) followed by mono- (26% ~ 32%), tri- (25% ~ 31%), tetra- (1.5% ~ 1.9 %), penta- (0.3% ~ 1%) in three platycodon accessions. Based on the SNP information obtained from RNA-seq analysis, we developed 12 PCR-based markers in Platycodon. The number of alleles ranged from two to seven with the average PIC value of 0.373. These 12 markers were applied to 21 platycodon accessions and a phylogenetic tree was constructed. The markers developed in this study could be introduced in molecular breeding program of platycodons. The SSR information obtained from RNA-seq analysis could be further utilized for developing genic-SSR markers in platycodons. Since platycodon is considered as an orphan crop, which has not been actively deployed for genetic study, the sequence information obtained from this study will contribute to further genetic improvements, genomic information and gene discovery in platycodon