ABSTRACT: Transcriptome profiling reveals differentially expressed genes between wizened flower bud and common flower buds in Chinese pear (Pyrus pyrifolia )
Project description:A custom oligoarray of Japanese pear (Pyrus pyrifolia) based on 9,812 independent ESTs from different tissues (fruits at various growth stages, vegetative and flower tissues) was designed and used for comprehensive investigation of gene expression before and during ripening (105 to 147 days after full bloom).
Project description:A custom oligoarray of Japanese pear (Pyrus pyrifolia) based on 9,812 independent ESTs from different tissues (fruits at various growth stages, vegetative and flower tissues) was designed and used for comprehensive investigation of gene expression before and during ripening (105 to 147 days after full bloom). Gene expression in fruit development of Japanese pear was measured from 105 to 147 days after full bloom (DAFB). 147 DAFB is the optimum maturity for eating. Two to three independent experiments were performed at each time (105 to 147 DAFB) using different trees for each experiment.
Project description:Bud mutation (bud sport) is mutation occurred in one branch in a tree and the mutant branch shows different phenotype from normal branches. Because bud mutation occurs in a part of plant body, genomic backgrounds of mutant branch and normal branches are the same, except some mutations. Therefore bud mutants are ideal material to identify key genes for important traits of crops. We studied M-bM-^@M-^XGiant LafM-bM-^@M-^Y, a bud mutant setting large fruit, which generated spontaneously in European pear M-bM-^@M-^XLa FranceM-bM-^@M-^Y tree. In M-bM-^@M-^XGiant LafM-bM-^@M-^Y, increase of cell size and DNA reduplication occurred specifically in fruit flesh. The DNA reduplication in M-bM-^@M-^XGiant LafM-bM-^@M-^Y was observed at 1 week before full bloom stage. This suggested that DNA reduplication observed in M-bM-^@M-^XGiant LafM-bM-^@M-^Y fruit is not endoreduplication, but endomitosis or nuclear fusion. To identify genes expressed differentially between in M-bM-^@M-^XGiant LafM-bM-^@M-^Y and in M-bM-^@M-^XLa FranceM-bM-^@M-^Y, microarray analysis was performed with RNA from receptacle (fruit flesh) at 1 week before full bloom stage. To isolate the receptacle, laser microdissection was applied. Genes encoding proteins localized in nucleus and cytoskeleton were up-regulated in M-bM-^@M-^XGiant LafM-bM-^@M-^Y. Among these genes, we found several genes which shared homology with previously described DNA reduplication related genes. These are candidates of responsible gene of M-bM-^@M-^XGiant LafM-bM-^@M-^Y mutation. The gene expression profiles between European pear (Pyrus communis) M-bM-^@M-^XLa FranceM-bM-^@M-^Y and its bud mutant M-bM-^@M-^XGiant LafM-bM-^@M-^Y were compared. RNA was extracted from receptacle which was isolated from flower bud at 1 week before full bloom stage by using laser microdissection. Three biological replications were analyzed.
Project description:Single-base resolution methylome of different flower buds from Pyrus pyrifolia reveals epigenomic changes in response to flower bud abortion
Project description:Dormancy of buds is a critical developmental process that allows plants to survive extreme seasonal variations in climate. Dormancy transition in leaf buds of Japanese pear leading cultivar M-bM-^@M-^XKosuiM-bM-^@M-^Y were investigated using 10 K cDNA microarray. Leaf buds collected on October (early endodormancy) and February (breaking stage) were used to monitor the changes in the transcriptome. Over 1000 genes were differentially expressed (p value < 0.05 and 2 fold change) when the early endodormant stage and breaking one were compared to each other. Functional classification revealed that the majority of genes were involved in response to abiotic/biotic stimulus and stress, signal transduction, and transcription. Among them, 76 and 22 genes were significantly (over 10 fold change) highly expressed in early endodormant stage and breaking stage, respectively, this result suggests that even in the endodormant stage, gene expression in the buds is high. Among them, several transcriptional factors were included. The quantitative real-time PCR analysis showed that at least three of their seasonal changes during endodormancy transition phases were similar to two DAM (dormancy-associated MADS box) genes isolated from Japanese pear, suggesting that they might be novel candidate genes associated to dormancy. The gene expression profiles between dormant and released leaf bud were compared.
Project description:In many plant species, flower stigma secretions are important in early stages of sexual reproduction. Previous chemical analysis and proteomic characterization of these exudates provided insights into their biological function. Nevertheless, the presence of nucleic acids in the stigma exudates has not been previously reported. Here we studied the stigma exudates of Pyrus communis, Pyrus pyrifolia and Pyrus syriaca, and showed them to harbor extracellular RNAs of various sizes. RNA sequencing revealed, for the first time, the presence of known Rosaceae mature micro-RNAs (miRs), also abundant in the stigma source tissue. Predicted targets of the exudate miRs in the Arabidopsis thaliana genome include genes involved in various biological processes. Several of these genes are pollen transcribed, suggesting possible involvement of exudate miRs in transcriptional regulation of the pollen. Moreover, extracellular miRs can potentially act across kingdoms and target genes of stigma interacting organisms/microorganisms, thus opening novel applicative avenues in HortSciences.
Project description:Transcriptional profiling of pear tree comparing a resistant/tolerant cultivar with a susceptible cultivar to the Stemphylium vesicarium fungus Rocha' pear is an economically important portuguese Pyrus communis L. cultivar very susceptible to the Stemphylium vesicarium pathogenic fungus, the brown spot agent, causing huge decrease on fruit quality and yield production. Field control of brown spot disease is based in systemic application of antifungal chemicals with high economic costs and dramatic consequences to public health and environmental pollution. Plant-pathogen interactions involve a series of events encompassing constitutive and induced plant defence responses whose dissection has been a research target for control many crop diseases. The biosynthesis of cell wall polymers and antifungal compounds appear to be an efficient physical and chemical barrier to infection.To understand the molecular responses behind defence mechanisms of resistant/tolerant and susceptible cultivars of Pyrus communis L. to the S. vesicarium fungus, cDNA microarray technology was used to identify the genes differentially expressed along a time course leaf inoculation between 'Rocha' pear cultivar (a high susceptible cultivar) and 'Ercolini' pear cultivar (a resistant/tolerant pear cultivar). This study aims to contribute with information on the molecular mechanisms involved in host-pathogen interactions responsible for pear tree brown spot disease and resistance to Stemphylium vesicarium. Experimental condition: 'Ercolini' vs 'Rocha' (each experiment including 5 plants from each cultivar). 3 time-points: water-inoculation (T0h), 6 hours after inoculation with S. vesicarium (T6h) and 24 hours after inoculation with S. vesicarium. Biological replicates: 3 in each time-point. One replicate per array.
Project description:The production of heather (Calluna vulgaris) in Germany is highly dependent on cultivars with mutated flower morphology, the so-called diplocalyx bud bloomers. So far, this unique flower type of C. vulgaris has not been reported in any other plant species. The flowers are characterised by an extremely extended flower attractiveness, since the flower buds remain closed throughout the complete flowering season. The flowers of C. vulgaris bud bloomers are male sterile, because the stamens are missing. Furthermore, petals are converted into sepals. Therefore the diplocalyx bud bloomer flowers consist of two whorls of sepals directly followed by the gynoecium. A broad comparison of wild type and bud bloomer’s flowers was undertaken to identify genes differentially expressed in the bud flowering phenotype and in the wild type of C. vulgaris. Transcriptome sequence reads were generated using next generation 454 sequencing of two flower type specific cDNA libraries. In total, 360,000 sequence reads were obtained, assembled to 12,200 contigs, functionally mapped, and annotated. Transcript abundances in wild type and bud bloomer’s libraries were compared and 365 differentially expressed genes detected. Among these differentially genes, CvPI was identified which is the orthologue of the Arabidopsis B gene PISTILLATA (PI) and considered as the most promising candidate gene. Quantitative PCR was performed to analyse the gene expression levels of two C. vulgaris B genes CvPI and CvAP3 in both flower types. CvAP3 which is the orthologue of the Arabidopsis B gene APETALA (AP3) turned out to be ectopically expressed in sepals of wild type and bud bloomer flowers. CvPI expression was proven to be reduced in the flowers of bud blooming cultivars. Differential expression patterns of the B-class genes CvAP3 and CvPI were identified to cause characteristics of flower morphology in C. vulgaris wild type and bud blooming flowers leading to the following hypotheses: ectopic expression of CvAP3 is a convincing explanation for the formation of a completely petaloid perianth in the wild type and the “bud flowering” phenotype. In C. vulgaris, CvPI is essential for determination of petal and stamen identity. The characteristic transition of petals into sepals potentially depends on the observed deficiency of CvPI and CvAP3 expression in bud blooming flowers. However, the complete loss of stamens in bud blooming flowers remains to be explained. two samples were analysed, each representing a flower type
Project description:Transcriptional profiling of pear tree comparing a resistant/tolerant cultivar with a susceptible cultivar to the Stemphylium vesicarium fungus Rocha' pear is an economically important portuguese Pyrus communis L. cultivar very susceptible to the Stemphylium vesicarium pathogenic fungus, the brown spot agent, causing huge decrease on fruit quality and yield production. Field control of brown spot disease is based in systemic application of antifungal chemicals with high economic costs and dramatic consequences to public health and environmental pollution. Plant-pathogen interactions involve a series of events encompassing constitutive and induced plant defence responses whose dissection has been a research target for control many crop diseases. The biosynthesis of cell wall polymers and antifungal compounds appear to be an efficient physical and chemical barrier to infection.To understand the molecular responses behind defence mechanisms of resistant/tolerant and susceptible cultivars of Pyrus communis L. to the S. vesicarium fungus, cDNA microarray technology was used to identify the genes differentially expressed along a time course leaf inoculation between 'Rocha' pear cultivar (a high susceptible cultivar) and 'Ercolini' pear cultivar (a resistant/tolerant pear cultivar). This study aims to contribute with information on the molecular mechanisms involved in host-pathogen interactions responsible for pear tree brown spot disease and resistance to Stemphylium vesicarium.
Project description:Bud dormancy is a crucial stage in perennial trees and allows survival over winter and optimal subsequent flowering and fruit production. Environmental conditions, and in particular temperature, have been shown to influence bud dormancy. Recent work highlighted some physiological and molecular events happening during bud dormancy in trees. However, we still lack a global understanding of transcriptional changes happening during bud dormancy. We conducted a fine tune temporal transcriptomic analysis of sweet cherry (Prunus avium L.) flower buds from bud organogenesis until the end of bud dormancy using next-generation sequencing. We observe that buds in organogenesis, paradormancy, endodormancy and ecodormancy are characterised by distinct transcriptional states, and associated with different pathways. We further identified that endodormancy can be separated in two phases based on its transcriptomic state: early and late endodormancy. We also found that transcriptional profiles of just 7 genes are enough to predict the main cherry tree flower buds dormancy stages. Our results indicate that transcriptional changes happening during dormancy are robust and conserved between different sweet cherry cultivars. Our work also sets the stage for the development of a fast and cost effective diagnostic tool to molecularly define the flower bud stage in cherry trees.