1,721,122 research outputs found
Genome editing: il futuro (prossimo) del miglioramento genetico delle piante
Full text linkGenome editing, or genome editing with engineered nucleases, is a technology that, using engineered nucleases, allows site-specific single-base mutations or the insertion, deletion or replacement of DNA sequences in a specific site in the genome of an organism. Genome editing is based on the induction of double strand breaks (DSBs) in the DNA in the locus of interest to introduce mutations in that locus. In fact, after DSB induction, the damage will be repaired by processes (the non-homologous end joining and/or the homology-directed repair), that occur
naturally in the cells and during which mutations may occur. DSBs can be induced by different nucleases, all capable of specifically recognising a locus in the genome. The most promising is the CRISPR/Cas system, for ease of designing nucleases with sequence specificity and for the fact that it can be used in nearly every organism. In the CRISPR/Cas9 system, the recognition of the DNA sequence to be modified is operated by an RNA sequence. After successful DNA DSB, the cell proceeds with the repair of DNA. Generally, the cell uses non-homologous end joining, which produces substitutions, insertions and deletions of nucleotides in the damaged DNA site, and usually leads to loss of function of the target gene. When using this mode, the genome editing can be considered a biological site-specific mutagenesis, different from the mutagenesis induced by physical or chemical agents which randomly induce mutations through the entire genome. On the contrary, when homology directed repair is involved, genome editing can be considered a predetermined biological mutagenesis that modifies or corrects the target gene in the sense determined by the investigator. Applying genome editing to plants requires also ancillary technologies, according to the species and cell types. First, in vitro culture techniques, especially protoplast cultures, might be necessary for the production of cells that can be subjected to the nuclease treatment. Then, transformation vectors (Agrobacterium, viruses or biolistic methods) are needed to enable the transfer of the components required for genome editing to the plant cell. The vectors may be stable or transient; in the latter case, both the possible cytotoxicity of constitutively expressed nucleases and the production of transgenic plants would be avoided. Concerning the first results obtained using this technology, mutations in target genes of cultivated plants were obtained mostly through non-homologous end joining for traits related to morphology, quality and to the resistance to pathogens and herbicides, in both herbaceous and woody species. Results were also reported exploiting
the homology-directed repair. Overall, the genome editing technology proved suitable to introduce precise and predictable gene mutations directly into elite cultivars, reducing the duration of traditional crossing and backcrossing breeding, with the possibility to modify more than one genes per experiment. Although many advances in genome editing technology have been achieved in recent years, some technical problems remain to be solved, including the need for increasing the efficiency of the system, the production of off-target mutations, the influence of chromatin structure on the editing efficiency, the possible side effects on genes lying close to target genes and the efficiency of the technology in polyploid species (where many copies of target genes occur). In conclusion, the CRISPR/Cas system has emerged as the most important tool for the future of genetics because of its simplicity, versatility and efficiency. It will have a major impact on both basic and applied research and will be used to produce cultivars with improved disease resistance, with a higher nutritional value, and able to survive climate changes, more suitable as bioenergy crops, producing useful chemicals and biomolecules
Analysis of a dehydrin encoding gene and its phylogenetic utility in the genus Helianthus
No full textCurrent status of genome editing in plants
No full textGenome editing is a revolutionary technology allowing the induction of site-specific mutations in all living organisms. In this review, we briefly introduce the genome editing methods with special emphasis on the CRISPR/Cas system. Then, with reference to crop plants, we report on the recent advances and open questions, and discuss their implications and perspectives for plant research and breeding
Variation of repetitive DNA sequences in progenies of regenerated plants of Pisum sativum.
No full textVariability in LTR-retrotransposon redundancy and proximity to genes between sunflower cultivars and wild accessions.
Full text linkThe sunflower (Helianthus annuus) genome contains a very large proportion of transposable
elements, especially long-terminal-repeat retrotransposons. Being knowledge on the
retrotransposon-related variability within this species still limited, we performed a quantitative and
qualitative survey of intraspecific variation of LTR-retrotransposon fraction of the genome across
different genotypes of H. annuus, using next generation sequencing technologies. First, we
characterized the repetitive component of a sunflower homozygous experimental line, using 454
reads, and prepared a library of retrotransposon-related sequences. Then, we analysed the LTRretrotransposon
fraction of 7 wild accessions and 8 cultivars of sunflowerby mapping Illumina reads
of the 15 genotypes onto the library. We observed large variations in redundancy among genotypes,
at both superfamily and family levels. In another analysis, we mapped Illumina paired reads of the
15 genotypes onto two sets of sequences, i.e. retrotransposons and protein-encoding sequences, and
evaluated the extent of retrotransposon proximity to genes in the 15 genomes by counting the
number of paired reads of which one mapped onto a retrotransposon and the other onto a gene.
Large variability among genotypes was ascertained also for retrotransposonproximity to genes.
Both retrotransposon redundancy and proximity to genes showed different behaviour among
retrotransposon families and also between cultivated and wild genotypes, indicating a possible
involvement in sunflower domestication
High-throughput analysis of transcriptome variation during water deficit in a poplar hybrid: a general overview
No full textPoplar interspecific hybrids are one of the most
important forest crops. In order to obtain data on molecular
responses of forest trees to drought, Illumina sequencing technology
was used to determine the sequence of most gene
transcripts. This approach identified genes that contribute to
tolerance to water-limiting environments, contributing to the
long-term aim of developing strategies to improve plant productivity
under drought. We generated 72,197,113 sequence
reads, each 51 nt in length, encompassing 3.68 Gb of sequence
from 12 cDNA libraries obtained from leaves of plants of a
hybrid between Populus deltoides and Populus nigra
subjected or not to moderate or severe drought. The expression
of 41,335 poplar genes included in the Populus trichocarpa
Phytozome database was studied by mapping Illumina cDNA
reads on poplar unigene models. Expressed genes were
characterised by gene ontology and by determining the metabolic
pathway to which they belong.Most genes detected were
expressed in control and drought-treated plants; however, a
number of genes thatwere observedwere significantly induced
or repressed by drought. Induction or repression of most genes
was more common after severe (relative water content around
55–60%) than aftermoderate water deficit (around 85 %) even
for genes that usually respond promptly to changes in environmental
conditions, such as those encoding transcription factors.
The dataset of expression profiles will be useful for future
studies on responses to other stimula and for crop improvement
of poplar
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