1,721,018 research outputs found
Benchmarking of Hi-C tools for scaffolding plant genomes obtained from PacBio HiFi and ONT reads
No full textThe implementation of Hi-C reads in the de novo genome assembly process allows the ordering of large regions of the genome in scaffolds and the generation of chromosome-level assemblies. Several bioinformatics tools have been developed for genome scaffolding with Hi-C, and each tool has advantages and disadvantages that need to be carefully evaluated before their adoption. We generated two de novo assemblies of Arabidopsis thaliana obtained from the same raw PacBio HiFi and Oxford Nanopore Technologies data. We scaffolded the assemblies implementing Hi-C reads with the scaffolders 3D-DNA, SALSA2, and YaHS, with the aim of identifying the tool providing the most accurate assembly. The scaffolded assemblies were evaluated according to contiguity, completeness, accuracy, and structural correctness. In our analysis, YaHS proved to be the best-performing bioinformatics tool for scaffolding de novo genome assemblies in Arabidopsis thaliana
Mode of reproduction is detected by Parth1 e Sex1 SCAR markers in a wide range of facultative apomictic Kentucky bluegrass varieties
No full textGametophytic apomixis in Kentucky bluegrass (Poa pratensis L.) involves the parthenogenetic development of unreduced eggs from aposporic embryo sacs. Marker-assisted selection for the mode of reproduction in P. pratensis would avoid costly and time-consuming phenotypic progeny tests. We developed and tested two SCAR primer pairs that are associated with the mode of reproduction in P. pratensis. The SCAR primers identified the apomictic and sexual genotypes among progenies of sexual x apomictic crosses with very low bias. Furthermore, when tested on a wide range of Italian and exotic P. pratensis germplasm, they were able to unequivocally distinguish sexual from apomictic genotypes. This system should, therefore, allow new selection models to be set up in this species
Legumes of the Sardinia Island: Knowledge on Symbiotic and Endophytic Bacteria and Interactive Software Tool for Plant Species Determination
Full text linkA meta-analysis was carried out on published literature covering the topic of interactive plant microbiology for botanical species of legumes occurring within the boundary of the Italian island Sardinia, lying between the Tyrrhenian and the western Mediterranean seas. Reports were screened for the description of three types of bacterial occurrences; namely, (a) the nitrogen-fixing symbionts dwelling in root nodules; (b) other bacteria co-hosted in nodules but having the ancillary nature of endophytes; (c) other endophytes isolated from different non-nodular portions of the legume plants. For 105 plant species or subspecies, over a total of 290 valid taxonomical descriptions of bacteria belonging to either one or more of these three categories were found, yielding 85 taxa of symbionts, 142 taxa of endophytes in nodules, and 33 in other plant parts. The most frequent cases were within the Medicago, Trifolium, Lotus, Phaseolus, and Vicia genera, the majority of symbionts belonged to the Rhizobium, Mesorhizobium, Bradyrhizobium, and Sinorhizobium taxa. Both nodular and extra-nodular endophytes were highly represented by Gammaproteobacteria (Pseudomonas, Enterobacter, Pantoea) and Firmicutes (Bacillus, Paenibacillus), along with a surprisingly high diversity of the Actinobacteria genus Micromonospora. The most plant-promiscuous bacteria were Sinorhizobium meliloti as symbiont and Bacillus megaterium as endophyte. In addition to the microbial analyses we introduce a practical user-friendly software tool for plant taxonomy determination working in a Microsoft Excel spreadsheet that we have purposely elaborated for the classification of legume species of Sardinia. Its principle is based on subtractive keys that progressively filter off the plants that do not comply with the observed features, eventually leaving only the name of the specimen under examination
Structural characterization and duplication modes of pseudogenes in plants
No full textWe identified and characterized the pseudogene complements of five plant species: four dicots (Arabidopsis thaliana, Vitis vinifera, Populus trichocarpa and Phaseolus vulgaris) and one monocot (Oryza sativa). Retroposition was considered of modest importance for pseudogene formation in all investigated species except V. vinifera, which showed an unusually high number of retro-pseudogenes in non coding genic regions. By using a pipeline for the classification of sequence duplicates in plant genomes, we compared the relative importance of whole genome, tandem, proximal, transposed and dispersed duplication modes in the pseudo and functional gene complements. Pseudogenes showed higher tendencies than functional genes to genomic dispersion. Dispersed pseudogenes were prevalently fragmented and showed high sequence divergence at flanking regions. On the contrary, those deriving from whole genome duplication were proportionally less than expected based on observations on functional loci and showed higher levels of flanking sequence conservation than dispersed pseudogenes. Pseudogenes deriving from tandem and proximal duplications were in excess compared to functional loci, probably reflecting the high evolutionary rate associated with these duplication modes in plant genomes. These data are compatible with high rates of sequence turnover at neutral sites and double strand break repairs mediated duplication mechanisms
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The Role of Expansins A in Petunia Development
Full text linkExpansins, a diverse set of proteins found in plants and some other organ-
isms, appear to play a key regulatory role in cell expansion, thereby serving critical
functions in plant morphogenesis, development, and adaptation to stress. We have
isolated a number of expansin genes from Petunia. Their ongoing functional analysis
provides evidence for their involvement in cell wall functions, including cellulose
metabolism, disruption of noncovalent cellulose/glycan bonds, and separation of the
cell wall matrix during cell expansion
Expression of human gltamic acid decarboxylase, a major autoantigen in Type 1 Diabetes, in transgenic plants
No full textThe wild olive of Sicily, Their past and potential contribution to the improvement of the cultivated varieties
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