Project description:Somatic variation is a valuable source of trait diversity in clonally propagated crops. In grapevine, which has been clonally propagated worldwide for centuries, important phenotypes such as white berry colour are the result of genetic changes caused by transposable elements. Additionally, epiallele formation may play a role in determining geo-specific (‘terroir’) differences in grapes and thus ultimately in wine. This genomic plasticity might be co-opted for crop improvement via somatic embryogenesis, but that depends on a species-specific understanding of the epigenetic regulation of transposable element (TE) expression and silencing in these cultures. For this reason, we used whole-genome bisulphite sequencing, mRNA sequencing and small RNA sequencing to study the epigenetic status and expression of TEs in embryogenic callus, in comparison with leaf tissue.
Project description:Somatic variants spontaneously appear during the vegetative multiplication of woody crops. The new white-berried grapevine cultivar Tempranillo Blanco (TB) originally appeared as a bud sport of the black skin-berried Tempranillo Tinto (TT) cultivar. To understand the origin of this variation, TT and TB genomes were sequenced. Structural variation and genetic segregation analyses uncovered that complex chromosome rearrangements consistent with chromothripsis, a catastrophic phenomenon recently described in human cancer, generated the variant genome of TB and the deletion of the color locus functional allele. Loss of heterozygosity and decreased copy number delimited alternating monosomic and disomic fragments in the distal arms of TB’s linkage groups 2 and 5. Hemizygous fragments collectively extended over 8.1 Mb and comprised 313 annotated genes. Clustered breakpoints for complex chromosome rearrangements disrupting linkage groups 2 and 5 were identified and junctions involved unbalanced inter- and intra-chromosome translocations and one unbalanced inversion. Signatures of blunt fusions or microhomology-mediated end joining mechanisms were detected at breakpoint junction flanks. Segregation distortion in TB-derived selfed progeny indicated linkage of rearrangements in a single copy of the affected chromosomes that was barely transmitted. Additionally to berry color loss, these dramatic changes have further viticultural consequences in TB associated to a decreased sexual fitness. Our findings show that chromothripsis spontaneously arise during mitotic multiplication of grapevine, evidencing that this phenomenon could contribute to clonal variation in woody crops and to the evolution of plant genomes. Grapevine GrapeGen GeneChips(R) were used for partial comparative genome hybridization between black-berried cultivars and their respective white-berried somatic variants. Differences in copy number were used to estimate chromosome deletions associated to the loss of berry color.
Project description:Background: Grape cultivars and wines are distinguishable by their color, flavor and aroma profiles. Omic analyses (transcripts, proteins and metabolites) are powerful tools for assessing biochemical differences in biological systems. Results: Berry skins of red- (Cabernet Sauvignon, Merlot, Pinot Noir) and white-skinned (Chardonnay, Semillon) wine grapes were harvested near optimum maturity from the same experimental vineyard and ˚Brix-to-titratable acidity ratio. Identical sample aliquots were analyzed for transcripts by grapevine whole-genome oligonucleotide microarray and RNA-seq technologies, proteins by nano-liquid chromatography-mass spectroscopy, and metabolites by gas chromatography-mass spectroscopy and liquid chromatography-mass spectroscopy. Principal components analysis of each of five Omic technologies showed similar results across cultivars in all Omic datasets. Comparison of the processed data of genes mapped in RNA-seq and microarray data revealed a strong Pearson's correlation (0.80). The exclusion of probesets associated with genes with potential for cross-hybridization on the microarray improved the correlation to 0.93. The overall concordance of protein with transcript data was low with a Pearson's correlation of 0.27 and 0.24 for the RNA-seq and microarray data, respectively. Integration of metabolite with protein and transcript data produced an expected model of phenylpropanoid biosynthesis, which distinguished red from white grapes, yet provided detail of individual cultivar differences. Conclusions: The five Omic technologies were consistent in distinguishing cultivar variation. There was high concordance between transcriptomic technologies, but generally protein abundance did not correlate well with transcript abundance. The integration of multiple high-throughput Omic datasets revealed complex biochemical variation amongst five cultivars of an ancient and economically important crop species.
Project description:In order to investigate the putative roles of the VvPLCP genes in grapevine resistance, the leaves-specific expression patterns of VvPLCPs were analyzed according to transcriptome data in two cultivars including V. vinifera cv. ‘Zitian Seedless’ and Vitis rootstocks ‘Kober 5BB’ when infected with P. viticola
Project description:Plants regenerated from tissue culture frequently show somaclonal variation. In this study we compared the transcriptomic and epigenetic state of embryogenic callus of grapevine with leaves from mature grapevine plants. In particular, we focussed on the expression of transposable elements and changes in siRNA abundance and genome-wide methylation in these tissues.
Project description:Plants regenerated from tissue culture frequently show somaclonal variation. In this study we compared the transcriptomic and epigenetic state of embryogenic callus of grapevine with leaves from mature grapevine plants. In particular, we focussed on the expression of transposable elements and changes in siRNA abundance and genome-wide methylation in these tissues.
Project description:Plants regenerated from tissue culture frequently show somaclonal variation. In this study we compared the transcriptomic and epigenetic state of embryogenic callus of grapevine with leaves from mature grapevine plants. In particular, we focussed on the expression of transposable elements and changes in siRNA abundance and genome-wide methylation in these tissues.