Project description:The objective of this study was to identify nutrient-responsive small RNAs in different tissues and in phloem sap of rape plants. miRNA microarrays containing all currently known plant miRNAs (Sanger miRBase versions 10.0, 10.1 and 11.0), and a set of unknown small RNAs cloned earlier from Brassica phloem sap (Bn_PsRNA) were used. The phloem, leaf and root response to nutrient deficiency were analyzed by removing either sulfate, copper or iron from the growth medium. The small RNA profile from phloem and inflorescence stems of plants grown under full nutrition conditions was also analyzed and compared. The study demonstrates that the phloem sap sRNA profile is distinct from that of the inflorescence stems, leaves and roots. Furthermore, we could identify phloem-enriched small RNAs and showed that some of them specifically accumulate in the phloem in response to nutrient deprivation.
Project description:High temperature stress results in yield loss and alterations to seed composition during seed filling in oilseed rape (Brassica napus). However, the mechanism underlying this heat response is poorly understood. In this study, we employed a microarray analysis with silique walls and seeds from the developing siliques (20 days after flowering) of Brassica napus that had undergone heat stress. Two-condition experiment, control vs heat stress, 2 time points
Project description:High temperature stress results in yield loss and alterations to seed composition during seed filling in oilseed rape (Brassica napus). However, the mechanism underlying this heat response is poorly understood. In this study, we employed a microarray analysis with silique walls and seeds from the developing siliques (20 days after flowering) of Brassica napus that had undergone heat stress.
Project description:Glutathione (GSH) is a tripeptide involved in controlling heavy metal movement in plants. Our previous study demonstrated that GSH, applied to plant roots site-specifically, inhibited Cd translocation from roots to shoots in oilseed rape plants (Brassica napus) cultured hydroponically. One of the factors of this inhibitory effect was due to activation of Cd efflux from root cells. To investigate the molecular mechanism triggered by root applied GSH in more detail, the Cd movement was monitored non-invasively using a positron-emitting tracer imaging system (PETIS). The Cd absorption and efflux process in roots were visualized successfully. The effects of GSH on Cd efflux from root cells were estimated by analyzing obtained imaging data. Another image analysis suggested that Cd return was activated by GSH, applied to roots, at the shoot base. Cutting the shoot base of oilseed rape plants significantly inhibited Cd efflux from root cells. These experimental results demonstrated the shoot base is playing important roles in distributing Cd in the plant bodies. Furthermore, DNA microarray analysis revealed that over 300 genes in the roots of oilseed rape plants responded to root applied GSH. Among them, transporter proteins, related to heavy metal movement in plants, and proteins related to changing the structure of cell walls were involved.
Project description:MicroRNAs are multifunctional non-coding short nucleotide molecules. Nevertheless, the role of miRNAs in the interactions between plants and necrotrophic pathogens is largely unknown. Here, we report the identification of the miRNA repertoire of the economically important oil crop oilseed rape (Brassica napus) and those involved in interacting with its most devastating necrotrophic pathogen Sclerotinia sclerotiorum. We identified 280 B. napus miRNA candidates, including 53 novel candidates and 227 canonical members or variants of known miRNA families, by high-throughput deep sequencing of small RNAs from both normal and S. sclerotiorum-inoculated leaves. Target genes of 15 novel candidates and 222 known miRNAs were further identified by sequencing of degradomes from the two types of samples. MicroRNA microarray analysis revealed that 68 miRNAs were differentially expressed between S. sclerotiorum-inoculated and uninoculated leaves. A set of these miRNAs target genes involved in plant defense to S. sclerotiorum and/or other pathogens such as NBS-LRR R genes and nitric oxygen and reactive oxygen species related genes. Additionally, three miRNAs target AGO1 and AGO2, key components of post-transcriptional gene silencing (PTGS). Expression of several viral PTGS suppressors reduced resistance to S. sclerotiorum. Arabidopsis mutants of AGO1 and AGO2 exhibited reduced resistance while transgenic lines over-expressing AGO1 displayed increased resistance to S. sclerotiorum in an AGO1 expression level-dependent manner. Moreover, transient over-expression of miRNAs targeting AGO1 and AGO2 decreased resistance to S. sclerotiorum in oilseed rape. Our results demonstrate that the interactions between B. napus and S. sclerotiorum are tightly regulated at miRNA level and probably involve PTGS.
Project description:MicroRNAs are multifunctional non-coding short nucleotide molecules. Nevertheless, the role of miRNAs in the interactions between plants and necrotrophic pathogens is largely unknown. Here, we report the identification of the miRNA repertoire of the economically important oil crop oilseed rape (Brassica napus) and those involved in interacting with its most devastating necrotrophic pathogen Sclerotinia sclerotiorum. We identified 280 B. napus miRNA candidates, including 53 novel candidates and 227 canonical members or variants of known miRNA families, by high-throughput deep sequencing of small RNAs from both normal and S. sclerotiorum-inoculated leaves. Target genes of 15 novel candidates and 222 known miRNAs were further identified by sequencing of degradomes from the two types of samples. MicroRNA microarray analysis revealed that 68 miRNAs were differentially expressed between S. sclerotiorum-inoculated and uninoculated leaves. A set of these miRNAs target genes involved in plant defense to S. sclerotiorum and/or other pathogens such as NBS-LRR R genes and nitric oxygen and reactive oxygen species related genes. Additionally, three miRNAs target AGO1 and AGO2, key components of post-transcriptional gene silencing (PTGS). Expression of several viral PTGS suppressors reduced resistance to S. sclerotiorum. Arabidopsis mutants of AGO1 and AGO2 exhibited reduced resistance while transgenic lines over-expressing AGO1 displayed increased resistance to S. sclerotiorum in an AGO1 expression level-dependent manner. Moreover, transient over-expression of miRNAs targeting AGO1 and AGO2 decreased resistance to S. sclerotiorum in oilseed rape. Our results demonstrate that the interactions between B. napus and S. sclerotiorum are tightly regulated at miRNA level and probably involve PTGS.
Project description:To identify oilseed rape genes with a potential role in N-remobilization during leaf senescence of developmentally old leaves in the lower canopy and young leaves in the upper canopy, transcriptomes of leaf number 4 and leaf number 8 of B. napus (cultivar Mozart) were analysed at different harvest time points under mild N deficiency and optimal N fertilization.
Project description:Oilseed rape (Brassica napus, B. napus) is one of the most important oil crops globally, contributing significantly to the world's supply of vegetable oil. However, its production is severely threatened by Sclerotinia stem rot, a disease caused by the broad-host-range fungus Sclerotinia sclerotiorum (Lib.) de Bary (S. sclerotiorum). We have investigated the gene expression of J9712 and W40-OE2 during different time periods of Sclerotinia sclerotiorum infection through RNA-Seq analysis.
Project description:The hemibiotrophic fungal pathogen Leptosphaeria maculans is the causal agent of blackleg disease in Brassica napus (canola, oilseed rape) and causes significant losses in crop yields worldwide. While genetic resistance has been used to mitigate the disease, little information about the genes and gene regulatory networks underlying blackleg resistance is currently available. High-throughput RNA sequencing and rigorous bioinformatics approaches revealed dynamic changes in the host transcriptome and identified plant defense pathways specific to the host-pathogen incompatible LepR1-AvrLepR1 interaction.