Project description:Apple pedicel vascular development array Twelvet apple samples. Biological replicates: 2 for each sample, independently grown and harvested.
Project description:Apple pedicel vascular development array Eight apple samples. Biological replicates: 2 for each sample, independently grown and harvested.
Project description:Effect of the presence of fruits on the expression of genes possibly involved in floral induction in the terminal meristem of spur bourse shoot. Investigation on mecanisms involved in Biennial Bearing in mature apple trees cultivar Royal Gala.
Project description:Effect of the presence of fruits on the expression of genes possibly involved in floral induction in the terminal meristem of spur bourse shoot. Investigation on mecanisms involved in Biennial Bearing in mature apple trees cultivar Royal Gala. Two-condition experiment : 'ON' trees (unthinned control) & 'OFF' trees (deflowered) for comparison. Three comparisons at sampling dates : 28, 48 and 119 days after full bloom (DAFB). Two dye switch biological replicates for each treatment and sampling date.
Project description:Apple is typically stored under low temperature and controlled atmospheric conditions to ensure a year round supply of high quality fruit for the consumer. During storage, losses in quality and quantity occur due to spoilage by postharvest pathogens. One important postharvest pathogen of apple is Botrytis cinerea. The fungus is a broad host necrotroph with a large arsenal of infection strategies able to infect over 1,400 different plant species. We studied the apple-B. cinerea interaction to get a better understanding of the defense response in apple. We conducted an RNAseq experiment in which the transcriptome of inoculated and non-inoculated (control and mock) apples was analyzed at 0, 1, 12 and 28 h post inoculation. Our results show extensive reprogramming of the apple's transcriptome with about 28.9 % of expressed genes exhibiting significant differential regulation in the inoculated samples. We demonstrate the transcriptional activation of pathogen-triggered immunity and a reprogramming of the fruit’s metabolism. We demonstrate a clear transcriptional activation of secondary metabolism and a correlation between the early transcriptional activation of the mevalonate pathway and reduced susceptibility, expressed as a reduction in resulting lesion diameters. This pathway produces the building blocks for terpenoids, a large class of compounds with diverging functions including defense. 1-MCP and hot water dip treatment are used to further evidence the key role of terpenoids in the defense and demonstrate that ethylene modulates this response.
Project description:The self-abscising characteristic of fruit is a prominent trait for labor-saving cultivation in apple (Malus × domestica). Up to 30 days after full bloom, early abscission leaves only central fruit in a cluster, while four lateral fruits are abscised. Since fruit abscission is possibly induced during earlier phases of fruit development, samples were collected at full bloom and 10 days after full bloom. Comparative analysis between central and lateral pedicels in self-abscising apple can be used to identify the genes that trigger the abscission mechanism, as the destinies of the pedicels in a cluster are obvious. Transcriptome analysis was performed using RNA-Seq to compare expression profiles between the surviving central pedicel to be survived and abscised lateral pedicel to be abscised from self-abscising apple. A total of 797,647 ESTs were assembled into 65,876 contigs which were annotated and analyzed with using Blast2GO. A total of 1,585 differentially expressed genes in central and lateral pedicels were identified using the NOISeq software. , and these genes were were characterized using the MapMan ontology software. Transcription factors involved in vascular bundle differentiation functioned in the central pedicel, while the signaling cascade of IAA14/SLR-ARF7, which progressed during lateral root emergence from primary roots, operated in lateral pedicels. Future studies should explore associations between the mechanisms of lateral root emergence and pedicel abscission during early phases of fruit development, as well as the interconnection among hormones.
Project description:Apple leaf spot caused by the Alternaria alternata f. sp. mali (ALT1) fungus is one of the most devastating diseases of apple (Malus × domestica). We identified a hairpin RNA (hpRNA)-mediated small RNAs, MdhpRNA277, from apple (cv. ‘Golden Delicious’) that is induced by infection with ALT1. MdhpRNA277 produces mdm-siR277-1 and mdm-siR277-2, which target five R genes, MdRNL1, MdRNL2, MdRNL3, MdRNL4, and MdRNL5, that are expressed at high levels in the resistant apple variety ‘Hanfu’ and at low levels in the susceptible variety ‘Golden Delicious’ following ALT1 infection. MdhpRNA277 is strongly induced in ‘Golden Delicious’ but was not induced in ‘Hanfu’ following ALT1 inoculation. The promoter activity of MdhpRNA277 was much stronger in ‘Golden Delicious’ than in ‘Hanfu’ after ALT1 inoculation. We identified a single nucleotide polymorphism (SNP) in the MdhpRNA277 promoter region between the susceptible variety ‘Golden Delicious’ (pMdhpRNA277-GD) and resistant variety ‘Hanfu’ (pMdhpRNA277-HF). The transcription factor MdWHy binds to pMdhpRNA277-GD, but not to pMdhpRNA277-HF. Transgenic ‘GL-3’ apple lines expressing pMdhpRNA277-GD: MdhpRNA277 were more susceptible to ALT1 infection than were those expressing pMdhpRNA277-HF:MdhpRNA277 due to induced mdm-siR277 accumulation and low levels of expression of the five target R genes. The failure of MdWHy to bind to pMdhpRNA277-HF might contribute to the low levels of MdhpRNA277 and mdm-siR277-1/-2 expression and the high levels of R gene expression and resistance to Alternaria leaf spot in resistant apple varieties. We confirmed that the SNP in pMdhpRNA277 is associated with Alternaria leaf spot resistance by analyzing the progeny of three additional crosses. The SNP identified in this study could be used as a marker to distinguish between apple varieties that are resistant or susceptible to Alternaria leaf spot.