Associations of the Seed Fatty Acid Composition of Sesame (Sesamum indicum L.) Germplasm with Agronomic Traits and FAD2 Variations.

Sesame is an important oilseed crop grown for human consumption in many countries, with a high commercial value due to its high oleic/linoleic acid ratio (O/L ratio). However, its properties may vary among different accessions. In the current study, 282 sesame accessions were evaluated to determine the effects of agronomic traits and genotypes on the O/L ratio. The O/L ratio was positively correlated with the oleic acid (C18:1), stearic acid (C18:0), and myristic acid (C14:0) concentrations, as well as the capsule zone length (CZL), capsule width (CW), and capsule length (CL), and negatively correlated with the linoleic acid (C18:2) and linolenic acid (C18:3) concentrations, the days to maturity (DTM), days to flowering (DTF), and the height of the first capsule-bearing node (HFC) (p < 0.05). In addition, the O/L ratio was affected by the FAD2 haplotype, as the Hap2 and Hap3 sesame accessions had lower O/L ratios. Therefore, we suggest that the increase and decrease in the contents of C18:1 and C18:2 are associated with the FAD2 haplotype. A total of 25 agronomic traits and fatty acid compositions were compared via statistical analysis, and accessions with a high O/L ratio were selected. The results of this study can be used as a basis for further research on the development of new sesame varieties through enhancing nutritional functionality.

A Genomic Evaluation of Six Selected Inbred Lines of the Naturalized Plants of Milk Thistle (Silybum marianum L. Gaertn.) in Korea.

Milk thistle (Silybum marianum) belongs to the Asteraceae family and is a medicinal plant native to the Mediterranean Basin. Silymarin in achene is a widely used herbal product for chronic liver disease. There is growing interest in natural medicine using milk thistle in Korea, but the raw material completely relies on imports. Despite its economic importance, phenotypic evaluations of native resources of milk thistle in Korea have not been carried out. In addition, genomic research and molecular marker development are very limited in milk thistle. In this study, we evaluated 220 milk thistle resources consisting of 172 accessions collected from the domestic market, and 48 accessions isolated from 6 accessions distributed by the National Agrobiodiversity Center in Korea. Six plant characteristics (height, seed weight, number of flowers, seed weight per flower, spine length, and color at harvest) were measured, and six samples (M01-M06) were selected to represent the genetic diversity of the population for genomic research. To develop PCR-based and co-dominant insertion/deletion (InDel) markers, we performed genome-wide InDel detection by comparing the whole-genome resequencing data of the six selected accessions with the reference genome sequence (GCA_001541825). As a result, 177 InDel markers with high distinguishability and reproducibility were selected from the 30,845 InDel variants. Unknowingly imported alien plant resources could easily be genetically mixed, and jeopardized seed purity can cause continuous difficulties in the development of high value-added agricultural platforms utilizing natural products. The selected plant materials and 177 validated InDel markers developed via whole-genome resequencing analysis could be valuable resources for breeding, conservation, and ecological studies of natives to Korea, along with acceleration of Silybum marianum industrialization.

Distinct Effects of Seed Coat and Flower Colors on Metabolite Contents and Antioxidant Activities in Safflower Seeds.

Safflower is an important oilseed crop cultivated primarily for its seeds, which have pharmaceutical properties. Color is an important agronomical trait that appears to be a prior parameter for evaluating the internal quality of plant seeds. This study employs 197 safflower accessions seeds to analyze how their seed coat and flower colors affect their total oil content, fatty acid composition, total phenolic content (TPC), N-(p-coumaroyl)serotonin (CS) and N-feruloylserotonin (FS) contents, and [2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS)] radical scavenging activities. Significant variations were observed in the targeted metabolite contents and antioxidant properties among genotypes. Notably, the linoleic acid content, total unsaturated fatty acid content, the ratio of total unsaturated fatty acid to total saturated fatty acid, CS, FS, ABTS, and DPPH scavenging capacities varied significantly based on seed coat color, with white-seeded genotypes having the highest average values of these parameters. Moreover, the linoleic acid content differed significantly (p < 0.05) among the genotypes with varying flower colors, with white-flowered accessions having the highest average content. Furthermore, genotypes K185105 (No. 75) and K175278 (No. 146) were identified as promising genetic resources with health benefits. Overall, these findings reveal that seed coat and flower colors distinctly affect metabolite contents and antioxidant properties in safflower seeds.

Seed Weight and Genotype Influence the Total Oil Content and Fatty Acid Composition of Peanut Seeds.

Peanut, an important oilseed crop cultivated worldwide as a dietary food, is a good food source with health benefits. To explore the potential benefits of peanuts as a food resource, 301 peanut accessions were evaluated to determine the effect of seed weight and genotype on total oil content and fatty acid composition. Total oil was extracted using the Soxhlet method and fatty acids were analyzed by gas chromatography mass spectrometry. Wide variations in the 100-seed weight, total oil content, and fatty acid profile were observed among genotypes and accession types. An effect of seed weight on the fatty acid composition of peanut seeds was observed. Increases in the oleic acid content and decreases in the linoleic acid content occurred in association with increases in the 100-seed weight. Moreover, the 100-seed weight, total oil content, and individual and total fatty acid contents, except arachidic acid, differed significantly (p < 0.001 or 0.05) among the accession types of landrace, cultivar, breeding line, and unknown. The discovery of this high diversity could contribute to further studies of peanut domestication and evolutionary classification. Our findings are important for the selection of peanut seeds with health benefits and development of new varieties of peanut with health benefits.

Development and Validation of SNP and InDel Markers for Pod-Shattering Tolerance in Soybean.

Pod-shattering causes a significant yield loss in many soybean cultivars. Shattering-tolerant cultivars provide the most effective approach to minimizing this loss. We developed molecular markers for pod-shattering and validated them in soybeans with diverse genetic backgrounds. The genes Glyma.16g141200, Glyma.16g141500, and Glyma.16g076600, identified in our previous study by quantitative trait locus (QTL) mapping and whole-genome resequencing, were selected for marker development. The whole-genome resequencing of three parental lines (one shattering-tolerant and two shattering-susceptible) identified single nucleotide polymorphism (SNP) and/or insertion/deletion (InDel) regions within or near the selected genes. Two SNPs and one InDel were converted to Kompetitive Allele-Specific PCR (KASP) and InDel markers, respectively. The accuracy of the markers was examined in the two recombinant inbred line populations used for the QTL mapping, as well as the 120 varieties and elite lines, through allelic discrimination and phenotyping by the oven-drying method. Both types of markers successfully discriminated the pod shattering-tolerant and shattering-susceptible genotypes. The prediction accuracy, which was as high as 90.9% for the RILs and was 100% for the varieties and elite lines, also supported the accuracy and usefulness of these markers. Thus, the markers can be used effectively for genetic and genomic studies and the marker-assisted selection for pod-shattering tolerance in soybean.

Protein, Amino Acid, Oil, Fatty Acid, Sugar, Anthocyanin, Isoflavone, Lutein, and Antioxidant Variations in Colored Seed-Coated Soybeans.

Different physiological and genetic studies show that the variations in the accumulation of pigment-stimulating metabolites result in color differences in soybean seed coats. The objective of this study was to analyze the nutrient contents and antioxidant potential in black, brown, and green seed-coated soybeans. Significant variations in protein (38.9-43.3%), oil (13.9-20.4%), total sugar (63.5-97.0 mg/g seed), total anthocyanin (3826.0-21,856.0 µg/g seed coat), total isoflavone (709.5-3394.3 µg/g seed), lutein (1.9-14.8 µg/g), total polyphenol (123.0-385.8 mg gallic acid/100 g seed), total flavonoid (22.1-208.5 mg catechin/100 g seed), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid (ABTS; 275.0-818.8 mg Trolox/100 g seed), and 2,2-diphenyl-1-picrylhydrazyl (DPPH; 96.3-579.7 mg Trolox/100 g seed) were found among the soybean genotypes. Ilpumgeomjeong2 contained the lowest protein but the highest oil and total sugar. The lowest oil-containing Wonheug had the highest protein content. Socheong2 was rich in all four variables of antioxidants. Anthocyanins were detected only in black soybeans but not in brown and green soybeans. The variation in isoflavone content was up to 5-fold among the soybean genotypes. This study could be a valuable resource for the selection and improvement of soybean because an understanding of the nutrient content and antioxidant potentials is useful to develop effective strategies for improving the economic traits; for example, the major emphasis of soybean breeding for fatty acids is to enhance the oleic and linoleic acid contents and to decrease linolenic acid content.

Quantitative Trait Locus Mapping for Drought Tolerance in Soybean Recombinant Inbred Line Population.

Improving drought stress tolerance of soybean could be an effective way to minimize the yield reduction in the drought prevailing regions. Identification of drought tolerance-related quantitative trait loci (QTLs) is useful to facilitate the development of stress-tolerant varieties. This study aimed to identify the QTLs for drought tolerance in soybean using a recombinant inbred line (RIL) population developed from the cross between a drought-tolerant 'PI416937' and a susceptible 'Cheonsang' cultivar. Phenotyping was done with a weighted drought coefficient derived from the vegetative and reproductive traits. The genetic map was constructed using 2648 polymorphic SNP markers that distributed on 20 chromosomes with a mean genetic distance of 1.36 cM between markers. A total of 10 QTLs with 3.52-4.7 logarithm of odds value accounting for up to 12.9% phenotypic variance were identified on seven chromosomes. Five chromosomes-2, 7, 10, 14, and 20-contained one QTL each, and chromosomes 1 and 19 harbored two and three QTLs, respectively. The chromosomal locations of seven QTLs overlapped or located close to the related QTLs and/or potential candidate genes reported earlier. The QTLs and closely linked markers could be utilized in maker-assisted selection to accelerate the breeding for drought tolerance in soybean.

QTL Mapping and Candidate Gene Analysis for Pod Shattering Tolerance in Soybean (Glycine max).

Pod shattering is an important reproductive process in many wild species. However, pod shattering at the maturing stage can result in severe yield loss. The objectives of this study were to discover quantitative trait loci (QTLs) for pod shattering using two recombinant inbred line (RIL) populations derived from an elite cultivar having pod shattering tolerance, namely "Daewonkong", and to predict novel candidate QTL/genes involved in pod shattering based on their allele patterns. We found several QTLs with more than 10% phenotypic variance explained (PVE) on seven different chromosomes and found a novel candidate QTL on chromosome 16 (qPS-DS16-1) from the allele patterns in the QTL region. Out of the 41 annotated genes in the QTL region, six were found to contain SNP (single-nucleotide polymorphism)/indel variations in the coding sequence of the parents compared to the soybean reference genome. Among the six potential candidate genes, Glyma.16g076600, one of the genes with known function, showed a highly differential expression levels between the tolerant and susceptible parents in the growth stages R3 to R6. Further, Glyma.16g076600 is a homolog of AT4G19230 in Arabidopsis, whose function is related to abscisic acid catabolism. The results provide useful information to understand the genetic mechanism of pod shattering and could be used for improving the efficiency of marker-assisted selection for developing varieties of soybeans tolerant to pod shattering.

Fruit Morphology, Citrulline, and Arginine Levels in Diverse Watermelon (Citrullus lanatus) Germplasm Collections.

Watermelon (Citrullus lanatus) is a non-seasonal, economically important, cucurbit cultivated throughout the world, with Asia as a continent contributing the most. As part of the effort to diversify watermelon genetic resources in the already cultivated group, this study was devoted to providing baseline data on morphological quality traits and health-beneficial phytonutrients of watermelon germplasm collections, thereby promoting watermelon research and cultivation programs. To this end, we reported morphological traits, citrulline, and arginine levels of watermelon genetic resources obtained from the gene bank of Agrobiodiversity Center, Republic of Korea, and discussed the relationships between each. Diverse characteristics were observed among many of the traits, but most of the genetic resources (>90%) were either red or pink-fleshed. Korean originated fruits contained intermediate levels of soluble solid content (SSC) while the USA, Russian, Tajikistan, Turkmenistan, Taiwan, and Uruguay originated fruits had generally the highest levels of soluble solids. The citrulline and arginine contents determined using the High Performance Liquid Chromatography (HPLC) method ranged from 6.9 to 52.1 mg/g (average, 27.3 mg/g) and 1.8 to 21.3 mg/g (average, 9.8 mg/g), respectively. The citrulline content determined using the Citrulline Assay Kit ranged from 6.5 to 42.8 mg/g (average, 27.0 mg/g). Resources with high citrulline and arginine levels contained low SSC, whereas red- and pink-colored flesh samples had less citrulline compared to yellow and orange.

Identification and quantification of selected metabolites in differently pigmented leaves of lettuce (Lactuca sativa L.) cultivars harvested at mature and bolting stages.

BACKGROUND: Identification and screening of cultivars rich in bioactive phytoconstituents can be potentially useful to make nutrient-dense dishes and in medicinal formulations. In this study, we have identified, characterized and quantified caffeoylquinic acids, dicaffeoylquinic acid, dicaffeoyltartaric acid, kaempferol conjugates, quercetin malonylglucoside, sesquiterpene lactones, and cyanidin in 22 lettuce cultivars at mature and bolting stages using UPLC-PDA-Q-TOF-HDMS, UPLC, and HPLC. RESULTS: The composition and contents of the studied metabolites and antioxidant activity varied significantly and depend on leaf color, cultivar type and stage of maturity. The main phenolic acid components of lettuce were quinic and tartaric acid derivatives, whereas kaempferol derivatives were the dominant flavonoids. The sum of the content of phenolic acids ranged from 18.3 to 54.6 mg/100 g DW and 15.5 to 54.6 mg/100 g DW, whereas the sum of the contents of flavonoids ranged from 9.2 to 25.9 mg/100 g DW and 14.9 to 83.0 mg/100 g DW in mature and bolting stage cultivars, respectively. The content of cyanidin, lactucin, lactucopicrin, and ABTS radical antioxidant activity were in the range of 0.3 to 9.7 (mature stage) and 0.5 to 10.2 mg/g DW (bolting stage), 1.8 to 41.9 (mature stage) and 9.7 to 213.0 (bolting stage) µg/g DW, 9.9 to 344.8 (mature stage) and 169.2 to 3888.2 (bolting stage) µg/g DW, and 12.1 to 29.0 (mature stage) and 15.7 to 30.3 (bolting stage) mg TE/g DW, respectively. The principal component analysis (PCA) showed that the green and red pigmented lettuce cultivars were grouped to the negative and positive sides of PC1, respectively, while the green/red pigmented cultivars were distributed throughout the four quadrants of the PCA plots with no prominent grouping. The loading plot showed that phenolic acids, flavonoids, and cyanidin are the most potent contributors to the radical scavenging activity of lettuce extracts. CONCLUSIONS: Lettuce at the bolting stage accumulate relatively high amount of sesquiterpene lactones (SLs), quercetin malonylglucoside (QMG), methylkaempferol glucuronide (MKGR), kaempferol malonylglucoside (KMG), and 3-O-caffeoylquinic acid (3-CQA) compared to the mature stage. Higher amount of phytoconstituents were found to be accumulated in the red pigmented lettuce leaves compared to the green lettuce leaves. In addition, the contents of most of the metabolites in lettuce seem to increase with age of the leaves. The presence of the two bitter SLs, lactucin and lactucopicrin, in significantly high amount in lettuce leaves at bolting stage could diminish consumer acceptance. However, alternatively, these leaves could be utilized by nutraceutical companies working to recover these compounds.

Genetic assessment of safflower (Carthamus tinctorius L.) collection with microsatellite markers acquired via pyrosequencing method.

A genetic evaluation of safflower germplasm collections derived from different geographical regions and countries will provide useful information for sustainable conservation and the utilization of genetic diversity. However, the molecular marker information is limited for evaluation of genetic diversity of safflower germplasm. In this study, we acquired 509 putative genomic SSR markers for sufficient genome coverage using next-generation sequencing methods and characterized thirty polymorphic SSRs in safflower collection composed of 100 diverse accessions. The average allele number and expected heterozygosity were 2.8 and 0.386, respectively. Analysis of population structure and phylogeny based on thirty SSR profiles revealed genetic admixture between geographical regions contrary to genetic clustering. However, the accessions from Korea were genetically conserved in distinctive groups in contrast to other safflower gene pool. In conclusion, these new genomic SSRs will facilitate valuable studies to clarify genetic relationships as well as conduct population structure analyses, genetic map construction and association analysis for safflower.