Genetic polymorphism of local Abkhazian grape cultivars

Local grape cultivars from different countries of the world are an important part of the gene pool of this culture. Of particular interest are the genotypes of the most ancient regions of viticulture. The territories of the subtropical zone of Georgia and the central part of Abkhazia belong to one of the centers of origin of the cultural grapevine. The purpose of the work was to genotype native Abkhazian grape cultivars, to study their genetic diversity based on DNA profiling data and to compare them with the genotypes of local varieties of other viticultural regions. Samples of plants were taken on the territory of the Republic of Abkhazia in private farmsteads and in the collection of the agricultural firm “Vina i Vody Abkhazii“ (“Wines and Waters of Abkhazia”). The genotyping of the Abkhazian cultivars Avasirhva, Agbizh, Azhapsh, Azhizhkvakva, Azhikvaca, Atvizh, Atyrkuazh, Achkykazh, Kachich was carried out using 14 DNA markers, 9 of which are standard microsatellite markers recommended for the identification of grape varieties. To improve our knowledge about the sizes of the identified alleles, we used the DNA of grape cultivars with a known allelic composition at the analyzed loci. Statistical analysis of the data showed that the observed heterozygosity for the analyzed loci exceeded expected values, which indicates a genetic polymorphism of the studied sample of varieties. Evaluation of genetic similarity within the analyzed group based on the results of genotyping at 14 loci showed that the cultivars Kachich and Azhapsh differed from the other Abkhazian varieties. The obtained DNA profiles of the Abkhazian cultivars were checked for compliance with DNA-fingerprints of grape varieties in the Vitis International Variety Catalogue. The Georgian varieties Azhizhkvakva and Tsitska turned out to be synonyms according to DNA profiles, two varieties from the Database (Italian Albana bianca and Georgian Ojaleshi) have differences in DNA-fingerprints from the varieties Atyrkuazh and Azhikvatsa only in one allele, respectively. When comparing the identified Abkhazian grape genotypes, their difference from the sample of Dagestan, Don, Greek, Turkish, Italian, Spanish, and French varieties and genetic similarity with the genotypes of Georgian grapes were shown.

Discrimination of a selected set of turmeric, ginger, fenugreek and coriander varieties using ISSR markers

DNA fingerprints are unique to individuals and can be used to identify individuals as in the case of conventional fingerprints. Plant DNA fingerprinting make use of various molecular markers for identifying newly released crop varieties and are all the more important in plant variety registration under the PPV&FR Act of 2001. The trade-related intellectual property rights (TRIPS) and the convention on biological diversity (CBD) insist on the establishment of identity and ownership of genotypes for enforcement of their provisions for securing protection to plant varieties as well as for regulating access to germplasm resources. DNA fingerprints, along with morphological markers, can be efficiently utilized for plant varietal identification, detection of duplicates and adulterants. Here in this particular study, the spice samples received at the DNA fingerprinting facility (DNAFF) of ICAR-Indian Institute of Spices Research (ICAR-IISR) from various centres of All India Coordinated Project on Spices (AICRPS) were DNA fingerprinted using inter simple sequence repeat (ISSR) markers. The DNA profile of a candidate variety vis-a-vis check variety is an essential prerequisite during submission of proposal for release of crop variety to central sub-committee on crop standards notification and release of varieties. The new varieties of turmeric, ginger, coriander and fenugreek were compared with the closely resembling check varieties for establishing distinctness for varietal registration. A total of 118 ISSR primers were screened in the above-given crops, to identify the distinct markers identifying the candidate from the check varieties. Using this technique, the DNAFF at ICAR-IISR could facilitate registration of turmeric varieties, Roma, Rasmi and Suroma; ginger varieties Suruchi, Suravi and Suprabha; coriander varieties, Suguna, Susthira and Suruchi, while varieties of turmeric, Uttara Rupanjana and Uttara Ranjini; fenugreek variety Ajmer fenugreek (AFg-5); coriander varieties Ajmer coriander (ACr-2) and Chhattisgarh Shri Chandra Hasini dhaniya-2 (ICS-4) are in the process of getting registration. ISSR markers were found to be appropriate for establishing distinctness of the new varieties of spices for securing varietal registration.

Absent from DNA and protein: genomic characterization of nullomers and nullpeptides across functional categories and evolution

Nullomers and nullpeptides are short DNA or amino acid sequences that are absent from a genome or proteome, respectively. One potential cause for their absence could be that they have a detrimental impact on an organism. Here, we identified all possible nullomers and nullpeptides in the genomes and proteomes of over thirty species and show that a significant proportion of these sequences are under negative selection. We assign nullomers to different functional categories (coding sequences, exons, introns, 5’UTR, 3’UTR and promoters) and show that nullomers from coding sequences and promoters are most likely to be selected against. Utilizing variants in the human population, we annotate variant-associated nullomers, highlighting their potential use as DNA ‘fingerprints’. Phylogenetic analyses of nullomers and nullpeptides across evolution shows that they could be used to build phylogenetic trees. Our work provides a catalog of genomic and proteome derived absent k-mers, together with a novel scoring function to determine their potential functional importance. In addition, it shows how these unique sequences could be used as DNA ‘fingerprints’ or for phylogenetic analyses.

The newly developed genomic-SSR markers uncover the genetic characteristics and relationships of olive accessions

Background Olive (Olea europaea L.) is an important oil and fruit crop worldwide, owning a rich germplasm with a large number of cultivars. Simple sequence repeats (SSRs) are excellent markers and have been used for the identification of olive cultivars. However, the limited number of SSR markers and the occurrence of confusion on the names of cultivars, as well as the possible appearance of clonal variation make it difficult to identify cultivars and interpret relationships among olive cultivars. Method SSR markers were designed based on trinucleotide repeat sequences by screening the whole genome of olive, and the polymorphic SSR markers were developed that were applied to the identification of 53 olive accessions. The genetic characteristics and relationships of these olive accessions were evaluated based on the developed SSR markers. Results Twenty-one highly polymorphic genomic-SSR markers were developed, covering most chromosomes of olive. These SSR markers could well distinguish all 53 olive accessions, confirming their effectiveness. DNA fingerprints of the 53 olive accessions were constructed based on the 21 SSR markers. The dendrogram clearly divided the tested accessions into two main groups, which was also supported by the results of principal coordinate analysis. A total of 31 private alleles were detected in 15 olive accessions, which reflected the genetic diversity within 53 olive accessions to some extent. Six homonymy cases were also clarified by genetic analysis. These results suggest that the newly developed olive SSR markers are informative for the exploitation, preservation and breeding of olive.

Towards sex identification of Asian Palmyra palm (Borassus flabelliferL.) by DNA fingerprinting, suppression subtractive hybridization andde novotranscriptome sequencing

BackgroundAsian Palmyra palm, the source of palm-sugar, is dioecious with a long juvenile period requiring at least 12 years to reach its maturity. To date, there is no reliable molecular marker for identifying sexes before the first bloom, limiting crop designs and utilization. We aimed to identify sex-linked markers for this palm using PCR-based DNA fingerprinting, suppression subtractive hybridization (SSH) and transcriptome sequencing.MethodsDNA fingerprints were generated between males and females based on RAPD, AFLP, SCoT, modified SCoT, ILP, and SSR techniques. Large-scale cloning and screening of SSH libraries andde novotranscriptome sequencing of male and female cDNA from inflorescences were performed to identify sex-specific genes for developing sex-linked markers.ResultsThrough extensive screening and re-testing of the DNA fingerprints (up to 1,204 primer pairs) and transcripts from SSH (>10,000 clones) and transcriptome data, however, no sex-linked marker was identified. Althoughde novotranscriptome sequencing of male and female inflorescences provided ∼32 million reads and 187,083 assembled transcripts, PCR analysis of selected sex-highly represented transcripts did not yield any sex-linked marker. This result may suggest the complexity and small sex-determining region of the Asian Palmyra palm. To this end, we provide the first global transcripts of male and female inflorescences of Asian Palmyra palm. Interestingly, sequence annotation revealed a large proportion of transcripts related to sucrose metabolism, which corresponds to the sucrose-rich sap produced in the inflorescences, and these transcripts will be useful for further understanding of sucrose production in sugar crop plants. Provided lists of sex-specific and differential-expressed transcripts would be beneficial to the further study of sexual development and sex-linked markers in palms and related species.