A total of 25 strains of Flammulina velutipes were analyzed to identify the genomic regions responsible for producing white-fruiting body. NGS data was yielded by using Illumina Hiseq platform. Short reads were filtered by quality score and read length were mapped on the reference genome (KACC42780). Between the white- and brown fruitbody forming strains, we found 9376 SNPs, of which 8178 were non-polymorphic and 1198 were polymorphic. There is a high possibility that SNPs can be detected among the white strains as homozygous because white phenotype is recessive in F. velutipes. Thus, we constructed SNP matrix within 8 white strains. SNPs discovered between mono3 and mono19, the parental monokaryotic strains of 4120 strain (white), were excluded from the candidate. If the genotypes of SNPs detected between white and brown strains were identical with those in mono3 and mono19 strains, they were included in candidate as a priority. As a result, if more than 5 candidates SNPs were localized in single gene, we regarded as they are possibly related to the white color. In F. velutipes genome, chr08: 950kb-2650kb, chr09: 500kb-1400kb, chr09: 2800kb-4350kb, and chr11: 2450kb-3500kb regions were identified to be associated with white fruitbody forming.

In this study, phenotypic distribution of 15 major fruit quality traits were analyzed using 252 progenies derived from a cross between ‘Tano Red’ (seed) and ‘Ruby Seedless’ (seedless), to obtain basic data for improving the breeding efficiency of grapevine cultivars. Berry skin color was dark red-violet in 46.4% of the progenies, which is the color of ‘Tano Red’ and ‘Ruby Seedless’, and berry shape was elliptic in 48.4%. Most of the progenies were very juicy with soft flesh, and closely related to the characteristics of ‘Tano Red’. Seeds were well developed in 67.1% of the progenies, rudimentary in 30.1%, and 2.8% were seedless, with seed weight being less than 0.15 g in 84.9% of the progenies. Among the 15 fruit quality traits assessed, bunch density, ease of berry detachment from pedicel, berry weight, berry seed number, berry longitudinal diameter, berry transverse diameter, berry soluble solids, and berry acidity showed normal distributions. Heritability of berry weight, berry longitudinal diameter, berry transverse diameter, berry soluble solids, and berry acidity was 0.89, 0.82, 0.78, 0.86, and 0.93, respectively. Berry weight was positively correlated with seed weight (r = 0.486**), presence of seeds (r = 0.483**), and seed number (r = 0.211**). Seed weight significantly increased with presence of seeds (r = 0.607**) and seed number (r = 0.725**). In addition, presence of seeds was positively correlated with seed number (r = 0.319**). These results could be useful for the identification of quantitative trait loci associated with fruit quality to assist in grapevine breeding.

본 연구에서는 토마토 MAB에 활용하고자 토마토 7 품종의 genome-wide SNPs 데이터베이스를 구축하고, MAB를 위한 분자마커 선발 프로그램을 개발하였다. 토마토 전사체 데이터를 NCBI-SRA에서 다운로드 하여 in silico 분석으로 SNP를 추출하였다. 전사체 데이터에서 추출된 SNP를 재료로 7 품종의 토마토 계통을 이용해 총 21개 교배조합별 SNP 분자마커를 선발하였고, primer가 이용 가능한 마커를 이용하여 데이터베이스를 구축하였다. 마커를 선발하기에 앞서 염색체의 분획으로 두 가지 방법을 사용하였는데, 물리적 거리에 따른 분획과 유전거리에 따른 분획 방법이다. 물리적 거리를 이용한 분획은 각 염색체를 동일한 크기의 5개의 구획으로 나누고, 한 구획 당 교배조합별 차이를 보이는 3개의 SNP를 선발하였다. 교배조합이 바뀔 때마다 이용 가능한 SNP가 자동으로 primer 정보와 함께 제공되도록 하였다. 유전거리를 반영한 분획 방법은 각 염색체의 유전적 거리를 측정하여 물리적 거리에 차등을 두어 염색체 구획을 설정하였다. 즉 재조합이 자주 일어나는 염색체 양끝 말단 부분은 구획을 조밀하게 나누어 MAB 마커 또한 많이 할당하여 자세히 조사하도록 구성하였다. 유전거리에 따른 마커 선발에는 1,924개의 tomato- EXPEN 2000 map 분자마커와 SNP 마커를 이용하였다. 교배조합별로 이용할 수 있는 마커를 12개 염색체 상에 그래픽적으로 제공함으로써 사용자가 쉽게 이해하고 이용할 수 있는 MAB 위한 마커 선발 프로그램을 개발하였다. 이러한 토마토 MAB용 분자마커를 제공하는 프로그램은 실제적인 여교잡 선발 육종에 적용하여 분자마커의 활용을 높이고, 육종효율을 증진시킬 것이다.

Gibberellic acid (GA) is a well-characterized plant hormone, which plays a critical role in various plant growth and development. including stem elongation, floral indcution and seed development. GA is known to cause enlargement of ripening fruits and, especially in grapevines, GA shows a unique function: the induction of seedlessness in seeded grape varieties. However, despite extensive previous studies about GA, there has been no clear verification of the mechanism that induces seedlessness in grapes. To understand how GA treatment results in artificial parthenocarpy of seeded grapes at molecular levels, we analyzed transcriptional changes in seeded grapes with and without GA application in various inflorescence developmental stages using RNA-seq. At 14 days before flowering (DBF), seeded grapes were treated with 100 ppm GA and clusters were collected at three developmental stages: 7 DBF, full bloom, and 5 days after flowering (DAF). Of a total of 28,974 genes that were mapped to grape genome reference sequences, 7,013 and 9,064 genes were up- and down-regulated, respectively, in the GA-treated grape as compared to the non-GA-treated control at 7 DBF, full bloom, and 5 DAF. Clustering analysis revealed that these genes could be grouped into 9 clusters with different expression patterns. We also carried out functional annotation based on gene ontology categories. There were significant differences in the expression of the GA and auxin-related gene families. These findings expand our understanding of the complex molecular and cellular mechanisms of GA-induced parthenocarpy of grapes and provide a foundation for future studies on seed development in grapevines.

Backcrossing is a plant breeding method most commonly used to incorporate one or a few genes into an adapted or elite variety. To facilitate MAB (marker-assisted backcrossing) in a practice breeding program, we developed a SNP database and a program for providing selected markers for background selection from genome-wide SNPs of seven tomato accessions downloaded from NCBI-SRA. We identified 425,935 SNPs among 21 parental combinations with data from seven transcriptomes and developed a SNP database. To select the optimized number of markers for background selection, we divided 12 chromosomes according to physical length and genetic length. Initially, each chromosome was equally divided into five blocks according to physical length, and three SNPs were positioned per block. Additionally, we applied the genetic distance calculated from the recombination rate because the frequency of recombination can vary greatly among chromosomal regions. When considering genetic distance, each chromosome was divided into fifteen blocks unequally and one marker composed of EXPEN-2000 was positioned per block. The program for background selection was designed to be simple and easy to use, and it is available at http://tgsol.seeders.co.kr/ index.php/tg/mab. When the user selects the parental combination, the program provides selected markers with primer information. The value of this program for tomato breeding will further increase if more accession numbers are added to the database.