Genetic variation of Carthamus tinctorius L. and related species revealed by SRAP analysis

Assessment of genetic diversity among 131 safflower (Carthamus tinctorius L.) accessions using peroxidase gene polymorphism (POGP) markers

BACKGROUND

Safflower (Carthamus tinctorius L.) is an old oilseed crop with a 1.4 GB genome size and its flowers are used for food coloring, dyes and pharmaceutical industries. It was domesticated from its putative wild ancestor Carthamus palestinus about forty-five hundred years ago in the fertile crescent region.The current study was aimed to determine the genetic diversity, population structure and to check the applicability of iPBS-retrotransposons markers.

METHODS AND RESULTS

Eleven POGP primers yielded 70 bands of which 61 were highly polymorphic with 87.14% polymorphism. A great level of genetic variation was examined with higher values of overall gene diversity (0.27), genetic distance (0.53), number of effective alleles (1.46), Shannon's information index (0.41) and polymorphism information contents (0.71). Analysis of molecular variance revealed high genetic variation with 79% within the population. The STRUCTURE, PCoA and Neighbor-joining analysis separated the safflower germplasm into 2 major populations and 1 un-classified population. The accessions which were from Asian countries i.e., China, Afghanistan, Turkey, Iran and Pakistan were genetically similar and clustered together in both populations A and B. The maximum genetic distance was measured 0.88 between Pakistan 26 x Pakistan 24.

CONCLUSION

Findings of this research such as maximum diversity indices, higher PIC values showed the effectiveness and utility of POGP markers for the evaluation of genetic relationships among safflower accessions. The results of this study also showed that POGP markers are less effective compared to ISSRs, iPBS-retrotransposons and DArTSeq markers. AMOVA showed high genetic variation (79%) within a population and maximum genetic distance was found between the accessions Pakistan 26- Pakistan 24 and may be suggested as candidate parents for future breeding activities of safflower. The accessions from the fertile crescent region were clustered together and proved the origin of safflower domestication. This study highlights genetic variation among safflower germplasm and could be helpfull for parental selection and planning for future breeding programs.

Genetic diversity, antifungal evaluation and molecular docking studies of Cu-chitosan nanoparticles as prospective stem rust inhibitor candidates among some Egyptian wheat genotypes

Wheat has a remarkable importance among cereals worldwide. Wheat stem and leaf rust constitute the main threats that destructively influence grain quality and yield production. Pursuing resistant cultivars and developing new genotypes including resistance genes is believed to be the most effective tool to overcome these challenges. This study is the first to use molecular markers to evaluate the genetic diversity of eighteen Egyptian wheat genotypes. Moreover, the molecular docking analysis was also used to assess the Cu-chitosan nanoparticle (CuChNp) treatment and its mode of action in disease control management. The tested genotypes were categorized into two main cluster groups depending on the similarity matrix, i.e the most resistant and susceptible genotypes to stem and leaf rust races. The results of SCoT primers revealed 140 polymorphic and 5 monomorphic bands with 97% polymorphism. While 121 polymorphic and 74 monomorphic bands were scored for SRAP primers (99% polymorphism). The genotypes Sakha 94, Sakha 95, Beni Sweif 4, Beni Sweif 7, Sohag 4 and Sohag 5 were resistant, while Giza 160 was highly susceptible to all stem rust races at the seedling stage. However, in the adult stage, the 18 genotypes were evaluated for stem and leaf rust-resistant in two different locations, i.e. Giza and Sids. In this investigation, for the first time, the activity of CuChNp was studied and shown to have the potential to inhibit stem and leaf rust in studied Egyptian wheat genotypes. The Spraying Cu-chitosan nanoparticles showed that the incubation and latent periods were increased in treated plants of the tested genotypes. Molecular modeling revealed their activity against the stem and leaf rust development. The SRAP and SCoT markers were highly useful tools for the classification of the tested wheat genotypes, although they displayed high similarities at the morphological stage. However, Cu-chitosan nanoparticles have a critical and effective role in stem and leaf rust disease control.

Molecular diversity assessment of a world collection of safflower genotypes by SRAP and SCoT molecular markers

Safflower (Carthamus tinctorius L.) is considered as an oil crop that is rich in medicinal and industrial properties. In this study, the genetic diversity of safflower was assessed using 12 polymorphic sequence-related amplified polymorphism (SRAPs) and 11 polymorphic start codon targeted (SCoT) markers in 100 genotypes of safflower gathered from different geographical regions of the world. The 23 primers generated a total of 227 polymorphism fragments with a mean of 68.2% within the range of 3 (SCoT 31 and SCoT 35) to 13 (SCoT 35) bands per primer. Polymorphism per primer ranged between 100% (in Me4-Em1) and 18.1% (in SCoT19), with an average of 36.76%. The polymorphism information contents of the SRAP and SCoT markers were 0.35 and 0.30, respectively, indicating that SRAP markers were more effective than SCoT markers for assessing the degree of genetic diversity of the safflower. The results of the analysis of molecular variance showed a significant difference across cultivated safflower genotypes possessing a high intra-population variation. The examined accessions were categorized into five clusters based on similarity centers: the Middle East containing Iran, Iraq, Turkey, and Tajikistan; the Far East, including India, Pakistan, and Korea; Europe; the American continent; and Africa, including Egypt, Sudan and Libya. The present study shows the effectiveness of employing the mixture of SRAP and SCoT markers in the identification of safflower genetic diversity that would be useful for conservation and population genetics of safflower improvement in further studies.

Development of Genomic Microsatellite Markers in Carthamus tinctorius L. (Safflower) Using Next Generation Sequencing and Assessment of Their Cross-Species Transferability and Utility for Diversity Analysis

BACKGROUND

Safflower (Carthamus tinctorius L.), an Asteraceae member, yields high quality edible oil rich in unsaturated fatty acids and is resilient to dry conditions. The crop holds tremendous potential for improvement through concerted molecular breeding programs due to the availability of significant genetic and phenotypic diversity. Genomic resources that could facilitate such breeding programs remain largely underdeveloped in the crop. The present study was initiated to develop a large set of novel microsatellite markers for safflower using next generation sequencing.

PRINCIPAL FINDINGS

Low throughput genome sequencing of safflower was performed using Illumina paired end technology providing ~3.5X coverage of the genome. Analysis of sequencing data allowed identification of 23,067 regions harboring perfect microsatellite loci. The safflower genome was found to be rich in dinucleotide repeats followed by tri-, tetra-, penta- and hexa-nucleotides. Primer pairs were designed for 5,716 novel microsatellite sequences with repeat length ≥ 20 bases and optimal flanking regions. A subset of 325 microsatellite loci was tested for amplification, of which 294 loci produced robust amplification. The validated primers were used for assessment of 23 safflower accessions belonging to diverse agro-climatic zones of the world leading to identification of 93 polymorphic primers (31.6%). The numbers of observed alleles at each locus ranged from two to four and mean polymorphism information content was found to be 0.3075. The polymorphic primers were tested for cross-species transferability on nine wild relatives of cultivated safflower. All primers except one showed amplification in at least two wild species while 25 primers amplified across all the nine species. The UPGMA dendrogram clustered C. tinctorius accessions and wild species separately into two major groups. The proposed progenitor species of safflower, C. oxyacantha and C. palaestinus were genetically closer to cultivated safflower and formed a distinct cluster. The cluster analysis also distinguished diploid and tetraploid wild species of safflower.

CONCLUSION

Next generation sequencing of safflower genome generated a large set of microsatellite markers. The novel markers developed in this study will add to the existing repertoire of markers and can be used for diversity analysis, synteny studies, construction of linkage maps and marker-assisted selection.

Genetic variability and population structure of the potential bioenergy crop Miscanthus sinensis (Poaceae) in Southwest China based on SRAP markers

The genus Miscanthus has great potential as a biofuel feedstock because of its high biomass, good burning quality, environmental tolerance, and good adaptability to marginal land. In this study, the genetic diversity and the relationship of 24 different natural Miscanthus sinensis populations collected from Southwestern China were analyzed by using 33 pairs of Sequence Related Amplified Polymorphism (SRAP) primers. A total of 688 bands were detected with 646 polymorphic bands, an average of 19.58 polymorphic bands per primer pair. The average percentage of polymorphic loci (P), gene diversity (H), and Shannon's diversity index (I) among the 24 populations are 70.59%, 0.2589, and 0.3836, respectively. The mean value of total gene diversity (HT) was 0.3373±0.0221, while the allelic diversity within populations (HS) was 0.2589±0.0136 and the allelic diversity among populations (DST) was 0.0784. The mean genetic differentiation coefficient (Gst=0.2326) estimated from the detected 688 loci indicated that there was 76.74% genetic differentiation within the populations, which is consistent with the results from Analysis of Molecular Variance (AMOVA) analysis. Based upon population structure and phylogenetic analysis, five groups were formed and a special population with mixed ancestry was inferred indicating that human-mediated dispersal may have had a significant effect on population structure of M. sinensis. Evaluating the genetic structure and genetic diversity at morphological and molecular levels of the wild M. sinensis in Southwest China is critical to further utilize the wild M. sinensis germplasm in the breeding program. The results in this study will facilitate the biofuel feedstock breeding program and germplasm conservation.

Genetic diversity and genetic relationships in Hyacinthaceae in India using RAPD and SRAP markers

Genetic diversity and relationship among three genera namely Drimia, Dipcadi and Ledebouria of Hyacinthaceae in India was studied using RAPD and SRAP markers. Twenty one RAPD primers and nine SRAP were used for analyzing 41 accessions. RAPD gave an average 12.6 markers per primer, while SRAP generated 10.1 markers per primer pair. The family emerged very diverged with high polymorphism. The study resolved the three genera into monophyletic groups corresponding to three subfamilies; Urginoideae, Hyacinthoideae and Ornithogaloideae. Drimia wightii emerged a very distinct species and species specific markers were obtained with both marker systems. AMOVA analysis also revealed the genera to be quite well diverged. The two markers showed high correlation (r = 0.932) in Mantel matrix crresspondance test. The combined data also showed a very good correlation with the respective markers individually.

Molecular diversity assessment using Sequence Related Amplified Polymorphism (SRAP) Markers in Vicia faba L

Sequence-related amplified polymorphism (SRAP) markers were used to assess the genetic diversity and relationship among 58 faba bean (Vicia faba L.) genotypes. Fourteen SRAP primer combinations amplified a total of 1036 differently sized well-resolved peaks (fragments), of which all were polymorphic with a 0.96 PIC value and discriminated all of the 58 faba bean genotypes. An average pairwise similarity of 21% was revealed among the genotypes ranging from 2% to 65%. At a similarity of 28%, UPGMA clustered the genotypes into three main groups comprising 78% of the genotypes. The local landraces and most of the Egyptian genotypes in addition to the Sudan genotypes were grouped in the first main cluster. The advanced breeding lines were scattered in the second and third main clusters with breeding lines from the ICARDA and genotypes introduced from Egypt. At a similarity of 47%, all the genotypes formed separated clusters with the exceptions of Hassawi 1 and Hassawi 2. Group analysis of the genotypes according to their geographic origin and type showed that the landraces were grouped according to their origin, while others were grouped according to their seed type. To our knowledge, this is the first application of SRAP markers for the assessment of genetic diversity in faba bean. Such information will be useful to determine optimal breeding strategies to allow continued progress in faba bean breeding.