Project description:Under natural growth conditions, plants experience various and repetitive biotic and abiotic stresses. Salicylic acid (SA) is a key phytohormone involved in the response to biotic challenges. Application of synthetic SA analogues can efficiently prime defense responses, and leads to improved pathogen resistance. Because SA analogues can result in long-term priming and memory, we identified genes for which expression was affected by the SA analogue and explored the role of DNA methylation in this memorization process. We show that treatments with an SA analogue can lead to long-term transcriptional memory of particular genes in Arabidopsis. We found that subsequent challenging of such plants with a bacterial elicitor reverted this transcriptional memory, bringing their expression back to the original pre-treatment level. We also made very similar observations in apple (Malus domestica), suggesting that this expression pattern is highly conserved in plants. Finally, we found a potential role for DNA methylation in the observed transcriptional memory behavior. We show that plants defective in DNA methylation pathways displayed a different memory behavior. Our work improves our understanding of the role of transcriptional memory in priming, and has important implication concerning the application of SA analogues in agricultural settings.
Project description:In order to identify primed (and memorized) genes resulting from BTH and/ or flg22 application, we performed a series of microarray-based transcription profiles. 14 days after propagation plants were treated the first time with the indicated treatment and second time 17 days after propagation with the indicated treatment. Plants were harvested and RNA was extracted 31 days after propagation. BTH was applied as formulated compound Bion. The sample name reflects the treatment order. Samples with the name water_water are control treatments which were treated 14 and 17 days after propaghation with water. The sample with the name Bion_flg22 was treated 14 days after germination with BTH and 17 days after germination flg22.
Project description:In order to identify primed (and memorized) genes resulting from BTH and/ or flg22 application, we performed a series of microarray-based transcription profiles. 7 days after germination Arabidopsis plants were treated the first time with the indicated treatment and second time 10 days after germination with the indicated treatment. Plants were harvested and RNA was extracted 21 days after germination. BTH was applied as formulated compound Bion. The sample name reflects the treatment order. Samples with the name water_water are control treatments which were treated 7 and 10 days after germination with water. The sample with the name Bion_flg22 was treated 7 days after germination with BTH and 10 days after germination flg22.
Project description:We performed Illumina sequencing of sRNA libraries prepared from juvenile and reproductive phase buds from the apple trees. A large number of sRNAs exemplified by 33 previously annotated miRNAs and 6 novel members displayed significant differential expression (DE) patterns in juvenile and reproductive stages. The study provides new insight into our understanding of fundamental mechanism of poorly studied phase transitions in apple and other woody plants and important resource for future in-depth research in the apple development.
Project description:To understand the molecular basis of viral diseases, transcriptome profiling has been widely used to correlate host gene expression change patterns with disease symptoms during viral infection in many plant hosts. We used infection of apple by Apple stem grooving virus (ASGV), which produces no disease symptoms, to assess the significance of host gene expression changes in disease development. We specifically asked the question whether such asymptomatic infection is attributed to limited changes in host gene expression. Using RNA-seq, we identified a total of 184 up-regulated and 136 down-regulated genes in apple shoot cultures permanently infected by ASGV in comparison with virus-free shoots cultures. As in most plant hosts showing disease symptoms during viral infection, these differentially expressed genes encode known or putative proteins involved in cell cycle, cell wall biogenesis, response to biotic and abiotic stress, development and fruit ripening, phytohormone function, metabolism, signal transduction, transcription regulation, translation, transport, and photosynthesis. Our data suggest that current approaches to correlate host gene expression changes under viral infection conditions to specific infection processes or disease symptom development, based on the interpretation of individual gene functions, have severe limitations. Integrative approaches that can take into account plant development stages, gene threshold levels as well as compensatory, synergistic and antagonistic effects may be necessary to develop a sound systems understanding of the biological significance of host gene expression changes during infection. Compare the transcript profiling of ASGV-infected asymptomatic apple planlets (AP-Vinfect) and virus-free apple plantlets (AP-Vfree) by deep sequencing using Illumina RNA-Seq to check whether lots of genes were modulated by ASGV infection.
Project description:To understand the impact of TCR affinity during priming on memory formation, we performed transcriptional profiling of OT-1 cells at different time points after stimulation with high- or low-affinity ligands. Our findings indicate that low-affinity stimulaation is associated with earlier memory formation.
Project description:Based on sensorial analysis over 4 years, 6 apple genotypes with contrasted fruit texture (mealy or not) were selected among a progeny. Apple samples were collected at 100 days after flowering (100 DAF), harvest (H), after 2 and 4 months of cold storage (60DAH and 120DAH respectively).
Project description:Based on sensorial analysis, 8 apple genotypes with contrasted fruit texture for mealiness were selected among a progeny. Apple samples were collected at 60 days after flowering (60DAF), 110 days after flowering (110DAF), harvest (Rec), and after 1 or 2 months of cold storage (1M and 2M respectively).