Genome-wide association studies of Ca and Mn in the seeds of the common bean (Phaseolus vulgaris L.).

SNP markers linked to genes controlling Ca and Mn uptake were identified in the common bean seeds using DArT-based association mapping (AM). The Ca concentration in the seeds varied between 475 and 3,100 mg kg-1 with an average of 1,280.9 mg kg-1 and the Mn concentration ranged from 4.87 to 27.54 mg kg-1 with a mean of 11.76 mg kg-1. A total of 19,204 SNP markers were distributed across 11 chromosomes that correspond to the haploid genome number of the common bean. The highest value of ΔK was determined as K = 2, and 173 common bean genotypes were split into two main subclusters as POP1 (Mesoamerican) and POP2 (Andean). The results of the UPGMA dendrogram and PCA confirmed those of STRUCTURE analysis. MLM based on the Q + K model identified a large number of markers-trait associations. Of the 19,204 SNPs, five (on Pv2, 3, 8, 10 and 11) and four (on Pv2, 3, 8 and 11) SNPs were detected to be significantly related to the Ca content of the beans grown in Bornova and Menemen, respectively in 2015. In 2016, six SNPs (on Pv1-4, 8 and 10) were identified to be significantly associated with the Ca content of the seeds obtained from Bornova and six SNPs (on Pv1-4, 8 and 10) from Menemen. Eight (on Pv3, 5 and 11) and four (on Pv2, 5 and 11) SNPs had a significant association with Mn content in Bornova in 2015 and 2016, respectively. In Menemen, eight (on Pv3, 5, 8 and 11) and 11 (on Pv1, 2, 5, 10 and 11) SNPs had a significant correlation with Mn content in 2015 and 2016, respectively.

Association mapping of magnesium and manganese concentrations in the seeds of C. arietinum and C. reticulatum.

Chickpea (Cicer arietinum L.) is one of the oldest and most important pulse crops grown and consumed all over the world, especially in developing countries. Magnesium (Mg) and manganese (Mn) are essential plant nutrients in terms of human health and many health problems arise in their deficiencies. The objectives of this study were to characterize genetic variability in the seed Mg and Mn concentrations and identify single nucleotide polymorphism (SNP) markers associated with these traits in 107 Cicer reticulatum and 73C. arietinum genotypes, using a genome wide association study. The genotypes were grown in four environments, characterized for Mg and Mn concentrations, and genotyped with 121,841 SNP markers. The population showed three-fold and two-fold variation for the Mg and Mn concentrations, respectively. The population structure was identified using STRUCTURE software, which divided 180 genotypes into two (K = 2) groups. Principal component analysis and neighbor joining tree analysis confirmed the results of STRUCTURE. A total of 4 and 16 consistent SNPs were detected for the Mg and Mn concentrations, respectively. The identified markers can be utilized in breeding of chickpea to increase Mg and Mn levels in order to improve human and livestock nutrition.

Identification of SNP Markers Associated with Iron and Zinc Concentrations in Cicer Seeds.

BACKGROUND: Cicer reticulatum L. is the wild progenitor of chickpea Cicer arietinum L., the fourth most important pulse crop in the world. Iron (Fe) and zinc (Zn) are vital micronutrients that play crucial roles in sustaining life by acting as co-factors for various proteins. AIMS AND OBJECTIVES: In order to improve micronutrient-dense chickpea lines, this study aimed to investigate variability and detect DNA markers associated with Fe and Zn concentrations in the seeds of 73 cultivated (C. arietinum L.) and 107 C. reticulatum genotypes. METHODS: A set of 180 accessions was genotyped using 20,868 single nucleotide polymorphism (SNP) markers obtained from genotyping by sequencing analysis. RESULTS: The results revealed substantial variation in the seed Fe and Zn concentration of the surveyed population. Using STRUCTURE software, the population structure was divided into two groups according to the principal component analysis and neighbor-joining tree analysis. A total of 23 and 16 associated SNP markers related to Fe and Zn concentrations, respectively were identified in TASSEL software by the mixed linear model method. Significant SNP markers found in more than two environments were accepted as more reliable than those that only existed in a single environment. CONCLUSION: The identified markers can be used in marker-assisted selection in chickpea breeding programs for the improvement of seed Fe and Zn concentrations in the chickpea.

Association mapping of loci linked to copper, phosphorus, and potassium concentrations in the seeds of C. arietinum and C. reticulatum.

Due to its high nutritional value, chickpea is one of the most important and cost-effective legumes for human diet. Nutrient elements, such as Cu, P, K have numerous essential functions for the human metabolism. In this study, association mapping of loci linked to the seed Cu, P and K concentrations were performed on a population consisting of 107 Cicer reticulatum and 73 Cicer arietinum individuals in four environments (two locations x two years). A total of 121,840 SNPs were genotyped across 180 individuals by GBS analysis. The association mapping between the SNP markers and the seed Cu, P, K concentrations were identified and eight SNPs were found to be significantly associated with variations in three nutrient elements in more than two environments This research suggests that association mapping is a useful methodology for the identification of loci controlling the Cu, P and K uptake in chickpea seeds for further association mapping, molecular breeding, and marker-assisted selection and plant breeding studies and provides a broader understanding of the relationship between the investigated Cicer species and the effects of environmental conditions.

Genetic assessment of common bean (Phaseolus vulgaris L.) accessions by peroxidase gene-based markers.

BACKGROUND: Peroxidase, a plant-specific oxidoreductase, is a heme-containing glycoprotein encoded by a large multigenic family in plants. Plant peroxidases (POXs, EC 1.11.1.7) play important roles in many self-defense interactions in plants. Here, 67 common bean (Phaseolus vulgaris L.) genotypes were studied using a POX gene-based marker method. Comparison of POX genes could resolve evolutionary relationships in common bean. RESULTS: Eighty fragments were obtained with 20 primer pairs that amplified one (POX8c) to eight (ATP29) bands, with a mean of four bands per primer pair. The average (polymorphic information content) PIC value for the POX products was 0.40. The maximum variation (93%) was found between Turkey (#33) and India (#52) and between Antalya (#33) and India (#53). The minimum variation (0%) was found among four pairs: Bozdag (#2) and Karadeniz (#38), Kirklareli (#11) and Turkey (#15, 16, 43), Bandirma (#13) and Turkey (#15, 16, 43), and Kirklareli (#10) and Bandirma (#22). UPGMA was used to discriminate the common bean genotypes into five clusters, while STRUCTURE software was used to investigate the genetic population structure. CONCLUSION: The results showed that POX gene family markers can be used to study genotypic diversity and provide new information for breeding programs and common bean improvement practices.

Association mapping for five agronomic traits in the common bean (Phaseolus vulgaris L.).

BACKGROUND: The common bean is the most important grain legume and a major source of protein in many developing countries. We analysed the following traits: pod fibre (PF), seeds per pod (SPP), plant type (PT), growth habit (GH), and days to flowering (DF) for a set of diverse common bean accessions and determined whether such traits were associated with amplified fragment length polymorphism (AFLP), simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers. RESULTS: In this study, 66 common bean genotypes were used and genotyped with 233 AFLP, 105 SNP and 80 SSR markers. The association analysis between markers and five traits was performed using a General Linear Model (GLM) in Trait Analysis by aSSociation, Evolution and Linkage (TASSEL). The population structure was determined using the STRUCTURE software, and seven groups (K = 7) were identified among genotypes. The associations for such traits were identified and quantified; 62 markers were associated with the five traits. CONCLUSION: This study demonstrated that association mapping using a reasonable number of markers, distributed across the genome and with the appropriate number of individuals harboured to detect DNA markers linked to the traits of PF, SPP, PT, GH and DF in common bean.

A consensus linkage map of lentil based on DArT markers from three RIL mapping populations.

BACKGROUND: Lentil (Lens culinaris ssp. culinaris Medikus) is a diploid (2n = 2x = 14), self-pollinating grain legume with a haploid genome size of about 4 Gbp and is grown throughout the world with current annual production of 4.9 million tonnes. MATERIALS AND METHODS: A consensus map of lentil (Lens culinaris ssp. culinaris Medikus) was constructed using three different lentils recombinant inbred line (RIL) populations, including "CDC Redberry" x "ILL7502" (LR8), "ILL8006" x "CDC Milestone" (LR11) and "PI320937" x "Eston" (LR39). RESULTS: The lentil consensus map was composed of 9,793 DArT markers, covered a total of 977.47 cM with an average distance of 0.10 cM between adjacent markers and constructed 7 linkage groups representing 7 chromosomes of the lentil genome. The consensus map had no gap larger than 12.67 cM and only 5 gaps were found to be between 12.67 cM and 6.0 cM (on LG3 and LG4). The localization of the SNP markers on the lentil consensus map were in general consistent with their localization on the three individual genetic linkage maps and the lentil consensus map has longer map length, higher marker density and shorter average distance between the adjacent markers compared to the component linkage maps. CONCLUSION: This high-density consensus map could provide insight into the lentil genome. The consensus map could also help to construct a physical map using a Bacterial Artificial Chromosome library and map based cloning studies. Sequence information of DArT may help localization of orientation scaffolds from Next Generation Sequencing data.