Project description:In the current study we have profiled changes in the transcriptome of somatic and reproductive tissues of B.rapa plants following heat shock stress exposure. For this we used Illumina GAIIx platform. We have demonstrated that the highest tissue-specific alterations in the transcriptome profile are detected in tissues that were not directly exposed to stress, namely, in the endosperm and pollen. The progeny of exposed plants also exhibited significant alterations in the gene expression as compared to progeny of control plants. Overall design: The transcriptome profile was assessed after heat shock treatment in the following tissues of Brassica rapa plants: parental leaves, inflorescence meristem, pollen, unfertilized ovules, 24-hour post-fertilization ovules, embryo, endosperm and leaf tissues of progeny plants. Please note that *diff_out.tar.gz contains all the standard output produced by cuffmerge and cuffdiff and each file content/format details are provided in the 'README.txt' file
Project description:In the current study we have profiled changes in the transcriptome of somatic and reproductive tissues of B.rapa plants following heat shock stress exposure. For this we used Illumina GAIIx platform. We have demonstrated that the highest tissue-specific alterations in the transcriptome profile are detected in tissues that were not directly exposed to stress, namely, in the endosperm and pollen. The progeny of exposed plants also exhibited significant alterations in the gene expression as compared to progeny of control plants.
Project description:In the current study we have profiled changes in the smRNome of somatic and reproductive tissues of B.rapa plants following heat shock stress exposure. For this we used Illumina GAIIx platform. We have demonstrated that the highest tissue-specific alterations in the smRNome profile are detected in tissues that were not directly exposed to stress, namely, in the endosperm and pollen. The progeny of exposed plants also exhibited significant alterations in the smRNA as compared to progeny of control plants.
Project description:Plants are able to maintain the memory of stress exposure throughout their ontogenesis and faithfully propagate it into the next generation. Recent evidence argues for the epigenetic nature of this phenomenon. Small RNAs (smRNAs) are one of the vital epigenetic factors because they can both affect gene expression at the place of their generation and maintain non-cell-autonomous gene regulation. Here, we have made an attempt to decipher the contribution of smRNAs to the heat-shock-induced transgenerational inheritance in Brassica rapa plants using sequencing technology. To do this, we have generated comprehensive profiles of a transcriptome and a small RNAome (smRNAome) from somatic and reproductive tissues of stressed plants and their untreated progeny. We have demonstrated that the highest tissue-specific alterations in the transcriptome and smRNAome profile are detected in tissues that were not directly exposed to stress, namely, in the endosperm and pollen. Importantly, we have revealed that the progeny of stressed plants exhibit the highest fluctuations at the smRNAome level but not at the transcriptome level. Additionally, we have uncovered the existence of heat-inducible and transgenerationally transmitted tRNA-derived small RNA fragments in plants. Finally, we suggest that miR168 and braAGO1 are involved in the stress-induced transgenerational inheritance in plants.
Project description:Biotic stress can induce plastic changes in fitness-relevant plant traits. Recently, it has been shown that such changes can be transmitted to subsequent generations. However, the occurrence and extent of transmission across different types of traits is still unexplored. Here, we assessed the emergence and transmission of herbivory-induced changes in Brassica rapa and their impact on interactions with insects. We analysed changes in morphology and reproductive traits as well as in flower and leaf volatile emission during two generations with leaf herbivory by Mamestra brassicae and Pieris brassicae and two subsequent generations without herbivory. Herbivory induced changes in all trait types, increasing attractiveness of the plants to the parasitoid wasp Cotesia glomerata and decreasing visitation by the pollinator Bombus terrestris, a potential trade-off. While changes in floral and leaf volatiles disappeared in the first generation after herbivory, some changes in morphology and reproductive traits were still measurable two generations after herbivory. However, neither parasitoids nor pollinators further discriminated between groups with different past treatments. Our results suggest that transmission of herbivore-induced changes occurs preferentially in resource-limited traits connected to plant growth and reproduction. The lack of alterations in plant-insect interactions was likely due to the transient nature of volatile changes.
Project description:BACKGROUND:Genome-wide maps of histone modifications have been obtained for several plant species. However, most studies focus on model systems and do not enforce FAIR data management principles. Here we study the H3K27me3 epigenome and associated transcriptome of Brassica rapa, an important vegetable cultivated worldwide. FINDINGS:We performed H3K27me3 chromatin immunoprecipitation followed by high-throughput sequencing and transcriptomic analysis by 3'-end RNA sequencing from B. rapa leaves and inflorescences. To analyze these data we developed a Reproducible Epigenomic Analysis pipeline using Galaxy and Jupyter, packaged into Docker images to facilitate transparency and reuse. We found that H3K27me3 covers roughly one-third of all B. rapa protein-coding genes and its presence correlates with low transcript levels. The comparative analysis between leaves and inflorescences suggested that the expression of various floral regulatory genes during development depends on H3K27me3. To demonstrate the importance of H3K27me3 for B. rapa development, we characterized a mutant line deficient in the H3K27 methyltransferase activity. We found that braA.clf mutant plants presented pleiotropic alterations, e.g., curly leaves due to increased expression and reduced H3K27me3 levels at AGAMOUS-like loci. CONCLUSIONS:We characterized the epigenetic mark H3K27me3 at genome-wide levels and provide genetic evidence for its relevance in B. rapa development. Our work reveals the epigenomic landscape of H3K27me3 in B. rapa and provides novel genomics datasets and bioinformatics analytical resources. We anticipate that this work will lead the way to further epigenomic studies in the complex genome of Brassica crops.
Project description:Genetics instruction in introductory biology is often confined to Mendelian genetics and avoids the complexities of variation in quantitative traits. Given the driving question "What determines variation in phenotype (Pv)? (Pv=Genotypic variation Gv + environmental variation Ev)," we developed a 4-wk unit for an inquiry-based laboratory course focused on the inheritance and expression of a quantitative trait in varying environments. We utilized Brassica rapa Fast Plants as a model organism to study variation in the phenotype anthocyanin pigment intensity. As an initial curriculum assessment, we used free word association to examine students' cognitive structures before and after the unit and explanations in students' final research posters with particular focus on variation (Pv = Gv + Ev). Comparison of pre- and postunit word frequency revealed a shift in words and a pattern of co-occurring concepts indicative of change in cognitive structure, with particular focus on "variation" as a proposed threshold concept and primary goal for students' explanations. Given review of 53 posters, we found ?50% of students capable of intermediate to high-level explanations combining both Gv and Ev influence on expression of anthocyanin intensity (Pv). While far from "plug and play," this conceptually rich, inquiry-based unit holds promise for effective integration of quantitative and Mendelian genetics.
Project description:Numerous regulatory genes participate in plant thermotolerance. In Arabidopsis, HEAT-INDUCED TAS1 TARGET2 (HTT2) is an important thermotolerance gene that is silenced by ta-siR255, a trans-acting siRNA. ta-siR255 is absent from heading Chinese cabbage (Brassica rapa ssp. pekinensis). Our previous attempt to overexpress the endogenous BrpHTT2 gene of heading Chinese cabbage (B. rapa ssp. pekinensis) failed because of cosuppression. In theory, heading Chinese cabbage can overexpress Arabidopsis HTT2 to improve thermotolerance in the absence of ta-siR255-mediated gene silencing and the weak potential of coexpression.To test the potential application of HTT2 in improving crop thermotolerance, we transferred p35S::HTT2 to heading Chinese cabbage. We tested the leaf electrical conductivity, hypocotyl elongation, and survival percentage of p35S::HTT2 plants subjected to high-temperature (38 °C) and heat-shock (46 °C) treatment. The leaf electrical conductivity of p35S::HTT2 seedlings under high temperature decreased but did negligibly change under heat shock. The hypocotyl length of p35S::HTT2 seedlings increased under high temperature and heat shock. The survival rate of p35S::HTT2 seedlings increased under heat shock. BrpHsfs, a subset of heat-shock factor genes, were upregulated in p35S::HTT2 plants under high-temperature and heat shock conditions. In the field, transgenic plants with HTT2 appeared greener and formed leafy heads earlier than wild-type plants.Exogenous HTT2 increased the survival rates of heat-shocked heading Chinese cabbage by promoting thermotolerance through decreasing electrical conductivity and extending hypocotyl length. Our work provides a new approach to the genetic manipulation of thermotolerance in crops through the introduction of exogenous thermotolerance genes.
Project description:Transcription profiling by array of 10 days old Brassica rapa ssp. chinensis seedlings treated with 2mM methyl jasmonate by spraying and harvesting 48 hours past treatment