In this study, we investigated the genetic diversity and population structure of the core collection of hexaploid wheat accessions in the Japanese wheat gene bank NBRP-Wheat. The core collection, consisting of 188 accessions of Triticum aestivum, T. spelta, T. compactum, T. sphaerococcum, T. macha and T. vavilovii, was intensively genotyped by DArTseq markers and consisted of 20,186 SNPs and 60,077 present and absent variations (PAVs). Polymorphic markers were distributed in all chromosomes, with a tendency for smaller numbers on the D-genome chromosomes. We examined the population structure by Bayesian clustering and principal component analysis with a general linear model. Overall, the core collection was divided into seven clusters. Non-admixture accessions in each cluster indicated that the clusters reflect the geographic distribution of the accessions. Both structure analyses strongly suggested that the cluster consisting of T. spelta and T. macha is out-grouped from other hexaploid wheat accessions. We performed genome-wide association analysis pilot studies for nine quantitative and seven qualitative traits and found marker-trait associations for all traits but one, indicating that the current core collection will be useful for detecting uncharacterized QTLs associated with phenotypes of interest.
Here we present “Restore and Renew,” a replicable framework for gathering and interpreting evolutionary, ecological, and genomic data in support of restoration practices. In an era of rapid climatic change and continuous widespread clearing, revegetation projects need to focus on producing resilient and long‐term self‐sustaining populations. Restore and Renew expands current knowledge of genetic provenance via genome‐scan data, environmental niche modeling (ENM), and site‐specific climate information. The sampling strategy is to obtain leaf tissue representing the distributions of over 100 species commonly used in restoration. We apply generalized dissimilarity modeling to genome‐wide single nucleotide polymorphism datasets from hundreds of samples. Species‐specific local provenances are obtained using a model that represents observed patterns of genetic variation across the landscape. Climate modeling is implemented to interpret genetic provenance boundaries in the context of current and future climatic conditions at the specified site. Results are presented in an easy‐to‐use webtool ( www.restore‐and‐renew.org.au), where the user simply selects their site of interest and a target species to obtain the size and distribution of local genetic provenance. Although Restore and Renew is not prescriptive, it allows restoration practitioners to make informed decisions on where to source material from, to fulfill their restoration scenario of choice. Two examples, Westringia fruticosa and Acacia suaveolens, are presented to demonstrate how the analytical pipeline responds to different ecological and evolutionary patterns. The webtool has multiple applications for biodiversity management and will continue to evolve with new species and analytical/interpretative outputs.
Pea, one of the founder crops from the Near East, has two wild species: Pisum sativum subsp. elatius, with a wide distribution centered in the Mediterranean, and P. fulvum, which is restricted to Syria, Lebanon, Israel, Palestine and Jordan. Using genome wide analysis of 11,343 polymorphic single nucleotide polymorphisms (SNPs) on a set of wild P. elatius (134) and P. fulvum (20) and 74 domesticated accessions (64 P. sativumlandraces and 10 P. abyssinicum), we demonstrated that domesticated P. sativum and the Ethiopian pea (P. abyssinicum) were derived from different P. elatius genepools. Therefore, pea has at least two domestication events. The analysis does not support a hybrid origin of P. abyssinicum, which was likely introduced into Ethiopia and Yemen followed by eco-geographic adaptation. Both P. sativum and P. abyssinicum share traits that are typical of domestication, such as non-dormant seeds. Non-dormant seeds were also found in several wild P. elatius accessions which could be the result of crop to wild introgression or natural variation that may have been present during pea domestication. A sub-group of P. elatius overlaps with P. sativum landraces. This may be a consequence of bidirectional gene-flow or may suggest that this group of P. elatius is the closest extant wild relative of P. sativum.
Understanding the evolutionary history of diversifying lineages and the delineation of evolutionarily significant units and species remains major challenges for evolutionary biology. Low‐cost representational sampling of the genome for single nucleotide polymorphisms shows great potential at the temporal scales that are typically the focus of species delimitation and phylogeography. We apply these markers to a case study of a freshwater turtle, Emydura macquarii, whose systematics has so far defied resolution, to bring to light a dynamic system of substantive allopatric lineages diverging on independent evolutionary trajectories, but held back in the process of speciation by low level and episodic exchange of alleles across drainage divides on various timescales. In the context of low‐level episodic gene flow, speciation is often reticulate, rather than a bifurcating process. We argue that species delimitation needs to take into account the pattern of ancestry and descent of diverging lineages in allopatry together with the recent and contemporary processes of dispersal and gene flow that retard and obscure that divergence. Underpinned by a strong focus on lineage diagnosability, this combined approach provides a means for addressing the challenges of incompletely isolated populations with uncommon, but recurrent gene flow in studies of species delimitation, a situation likely to be frequently encountered. Taxonomic decisions in cases of allopatry often require subjective judgements. Our strategy, which adds an additional level of objectivity before that subjectivity is applied, reduces the risk of taxonomic inflation that can accompany lineage approaches to species delimitation.
Precise utilization of wild genetic resources to improve the resistance of their cultivated relatives to environmental growth limiting factors, such as salinity stress and diseases, requires a clear understanding of their genomic relationships. Although seriously criticized, analyzing these relationships in tribe Triticeae has largely been based on meiotic chromosome pairing in hybrids of wide crosses, a specialized and labourious strategy. In this study, DArTseq, an efficient genotyping-by-sequencing platform, was applied to analyze the genomes of 34 Triticeae species. We reconstructed the phylogenetic relationships among diploid and polyploid Aegilops and Triticum species, including hexaploid wheat. Tentatively, we have identified the diploid genomes that are likely to have been involved in the evolution of five polyploid species of Aegilops, which have remained unresolved for decades. Explanations which cast light on the progenitor of the A genomes and the complex genomic status of the B/G genomes of polyploid Triticumspecies in the Emmer and Timopheevi lineages of wheat have also been provided. This study has, therefore, demonstrated that DArTseq genotyping can be effectively applied to analyze the genomes of plants, especially where their genome sequence information are not available.
Characterization is most important for correct identification of plants. It helps to understand the genetic diversity, to trace out the phylo-genetic relationship, taxonomical status, registration, plant variety protection, farmer’s right etc. The use of biochemical and molecular markers for genetic diversity analysis as a selection tool is a high priority area for new orchid cultivars and the exploitation of species diversity. Biochemical markers, molecular markers and DNA sequence analysis allow a more complete characterization and understanding of the genetic relationships between species and cultivars. Various types of techniques are used to estimate genetic studies such as isozymes, allozymes, phyto-chemical and DNA markers like amplified fragment length polymorphism (AFLP), cleaved amplified polymorphic sequence (CAPS), DNA amplification fingerprinting (DAF), diversity arrays technology (DArT), next generation sequencing technology (NGST), expressed sequence tags (EST), inter-simple sequence repeat (ISSR), microsatellite primed PCR (MPPCR), multiplexed allele-specific diagnostic assay (MASDA), random amplified microsatellite polymorphisms (RAMP), random amplified microsatellites (RAM), random amplified polymorphic DNA (RAPD), restriction fragment length polymorphism (RFLP), sequence characterized amplified regions (SCAR), sequence specific amplification polymorphisms (S-SAP), sequence tagged microsatellite site (STMS), sequence tagged site (STS), short tandem repeats (STR), simple sequence length polymorphism (SSLP), simple sequence repeats (SSRs), single nucleotide polymorphism (SNP), single primer amplification reactions (SPAR) and variable number tandem repeat (VNTR). Among these techniques, some techniques have been used for genetic diversity analysis of orchid. Today, new techniques are frequently being developed and no such techniques are ideal yet these fulfill all requirements needed by plant researchers. Each technique has its own advantages and limitations. This review is an attempt to discuss a basic description of different biochemical and molecular techniques that can be utilized for genetic studies in orchids.
(PDF) Advances in biochemical and molecular marker techniques and their applications in genetic studies of orchid: A review. Available from: https://www.researchgate.net/publication/329026574_Advances_in_biochemical_and_molecular_marker_techniques_and_their_applications_in_genetic_studies_of_orchid_A_review [accessed Jan 09 2019].
Crop landraces embody a source of beneficial genes potentially providing endurance to environmental stress and other agronomic qualities including yield. Our study included 88 snake melon accessions (Cucumis melo var. flexuosus) collected from 9 districts in the Palestinian West-Bank. These accessions represent four landraces of Palestinian snake melon: Green, and White Baladi, and Green, and White Sahouri.
This is the first report on successful application of genotyping by sequencing in snake melon. Nine thousand seven hundred fifty single-nucleotide polymorphism (SNP) and 7400 DArTseq genetic markers were employed to evaluate genetic biodiversity and population structure of Palestinian snake melon germplasm collection. Clustering based on neighbor-joining-analysis, principle coordinate and Bayesian model implemented in Structure showed that patterns of genetic diversity of snake melon landraces depends on their geographical source and unraveled the presence of two major local landraces (Sahouri, and Baladi) with accessions from each group clustering together. A significant correlation was observed between both types of markers in Mantel correlation test. A significant association between genetic and geographic matrices (P < 0.0001) was also detected. AMOVA indicated that majority of variation (90%) was due to the difference within accessions.
The Palestinian landraces seem to have unique genes that may allow the enhancement of the global snake melon gene pool and developments of the plant production worldwide. Our subsequent objective is to detect genotypes with promising qualities and to conduct association mapping studies concentrating on Fusarium-wilt resistance, yield, and environmental stresses.
Male sterility is of high importance in hybrid seed production of hot and sweet peppers. Genic (or nuclear) male sterility (GMS) is a simply inherited (usually monogenic recessive) and highly stable trait. However, one major disadvantage of using GMS is 1:1 segregation of male sterile to male fertile plants in every subsequent generation. Molecular markers tightly linked to genic male sterility (ms) genes would facilitate an efficient and rapid transfer of ms genes into different genetic backgrounds through marker-assisted backcrossing. The two non-allelic genic male sterility genes ms3 and msw in hot and sweet pepper backgrounds, respectively, are monogenic recessive. Genotyping by sequencing (GBS) in an F2 population segregating for ms3 gene in hot pepper and in an F6 inbred near-isogenic line (NIL) population segregating for msw gene in sweet pepper yielded 9,713 and 7,453 single nucleotide polymorphism markers, respectively. Four candidate SNPs co-segregating with ms3 gene and one co-segregating with msw gene were identified by bulk segregant analysis and physically mapped to chromosomes 1 and 5, respectively. In hot pepper, two markers [HPGMS2 (CAPS) and HPGMS3 (dCAPS)] located 3.83 cM away from the ms3 gene and in sweet pepper the dCAPS marker SPGMS1 co-segregated (completely linked) with the msw gene were developed. These markers will increase the efficacy of the male sterility genes for pepper breeding, as they can be useful in developing the genic male sterile lines in parental inbred lines of commercial hybrids through marker-assisted backcrossing, hybrid seed production, and genetic purity testing of hybrid seeds.
A high‐resolution consensus linkage map of Triticum monococcum was assembled from two separate maps involving domesticated, feral and wild einkorn wheat accessions. The genotyping‐by‐sequencing (GBS) approach based on DArTseq markers yielded overstretched maps. Deleting all markers with missing data and then converting dubious singletons to missing data produced two maps of about 1,380 cM, close to the published genome size. The consensus map spanned 1,562 cM, had one bin mapped every 0.92 cM and showed only one gap > 10 cM. Chromosome length varied between 151 cM (chromosome 4) and 270 cM (chromosome 7). The consensus map was compared to other A‐genome maps, and the sequences of genetically mapped DArTseq were used to anchor contigs of the T. monococcum, T. urartu and T. aestivum draft genomes based on sequence homology to assess colinearity and to assign mapped markers to the seven chromosomes of the bread wheat A‐genome. Finally, an in silico functional characterization of the sequences was performed. This high‐resolution map will facilitate QTL and association analysis and assist the genome assembly of the einkorn genome.
The development and utilization of biochemical and molecular markers are becoming widely used in floricultural crops for varying purposes including genetic studies, qualitative as well as quantitative traits, genotype fingerprinting, phylogenetic studies and mapping populations.