Project description:•Cutin and suberin are lipid polyesters deposited in specific apoplastic compartments. Their fundamental roles in plant biology include controlling the movement of gases, water and solutes, and conferring pathogen resistance. Both cutin and suberin have been shown to be present in the Arabidopsis seed coat where they regulate seed dormancy and longevity. •In this study, we use accelerated and natural aging seed assays, glutathione redox potential measures, optical and transmission electron microscopy and gas chromatography-mass spectrometry to demonstrate that increasing the accumulation of lipid polyesters in the seed coat is the mechanism by which the AtHB25 transcription factor regulates seed permeability and longevity. •Chromatin immunoprecipitation during seed maturation revealed that the lipid polyester biosynthetic gene LACS2 (long-chain acyl-CoA synthetase 2) is a direct AtHB25 binding target. Gene transfer of this transcription factor to wheat and tomato demonstrates the importance of apoplastic lipid polyesters for the maintenance of seed viability. •Our work establishes AtHB25 as a trans-species regulator of seed longevity and has identified the deposition of apoplastic lipid barriers as a key parameter to improve seed longevity in multiple plant species.
Project description:Manipulating the activity of transcription factor (TF) to regulate animal’s longevity is achieved in different species. However, deciphering the pro-longevity transcriptional programme triggered by the TFs activity is challenging. One obstacle is the multifunctional feature of TFs. The physiological functions of single TF could be diverse and tissues-dependent. The other is the gene regulatory network among the TFs, where multiple TFs can have synergetic or antagonistic impact on the same target genes. Here, we show Xbp1s overexpression in gut and fat body can extend lifespan in Drosophila. Importantly, Xbp1s activity triggers distinct transcriptional programmes in the two tissues, and Xbp1s induction in both tissues are beneficial for longevity. Furthermore, we reveal a pro-longevity gene regulatory network in the fat body, where Xbp1s and dFOXO impinge on the same target genes and induce identical transcriptional outcomes. dfoxo overexpression requires Xbp1 to extend lifespan. Lastly, inducing Xbp1u, the precursor of Xbp1s, can also extend lifespan without triggering massive transcriptome change.
Project description:Many genes involve in pathogenicity and virulence are induced only in plant or in the presence of host components. Plant apoplast is the primary site of infection for P. syringae, which obtain nutrients directly from apoplastic fluid of host plants. In this work we investigated the effect of apoplastic fluid on the transcriptomic profile of the bacterium, when grown at low temperature in minimal medium with or without apoplastic fluid extracted from healthy bean leaves.
Project description:We identified that Drosophila FoxA transcription Fork Head (FKH) function is necessary for reduced insulin signalling and rapamycin induced longevity. Furthermore, we determined that FKH function in the gut tissue alone is sufficient to extend lifespan. We carried out RNA-sequencing in gut tissue on controls (daGS;InRDN>GFP- RNAi) and reduced insulin signalling background upon control RNAi (daGS;InRDN>GFPRNAi +RU486) and upon FKH RNAi (daGS;InRDN>FKH- RNAi +RU486). InR-DN stock used: K1409A.
Project description:The extracellular space within plant leaves is called the apoplast, and functions as a key battlefield between plants and pathogens. Previously, we have shown that apoplastic wash fluid purified from Arabidopsis leaves contains small RNAs (sRNAs). To investigate whether these RNAs are encapsulated inside extracellular vesicles (EVs), we treated EVs isolated from Arabidopsis leaves with the protease trypsin and RNase A, which should degrade RNAs located outside of EVs, but not those located inside. These analyses revealed that apoplastic RNAs are mostly located outside of EVs and are associated with proteins. Additional analyses of these extracellular RNAs (exRNAs) revealed that they are made up both sRNAs and long non-coding RNAs (lncRNAs), including circular RNAs (circRNAs). We also found that exRNAs are highly enriched in the post-transcriptional modification N6-methyladenine (m6A). Consistent with this, we identified a putative m6A-binding protein in apoplastic wash fluids, GLYCINE-RICH RNA BINDING PROTEIN 7 (GRP7), as wells as the small RNA-binding protein ARGONAUTE2 (AGO2). These two proteins co-immunoprecipitated with each other, and with lncRNAs, including circRNAs. Mutation of GRP7 or AGO2 caused changes in both the sRNA and lncRNA content of apoplastic wash fluid, suggesting that these proteins contribute to the secretion and/or stabilization of exRNAs.
Project description:The extracellular space within plant leaves is called the apoplast, and functions as a key battlefield between plants and pathogens. Previously, we have shown that apoplastic wash fluid purified from Arabidopsis leaves contains small RNAs (sRNAs). To investigate whether these RNAs are encapsulated inside extracellular vesicles (EVs), we treated EVs isolated from Arabidopsis leaves with the protease trypsin and RNase A, which should degrade RNAs located outside of EVs, but not those located inside. These analyses revealed that apoplastic RNAs are mostly located outside of EVs and are associated with proteins. Additional analyses of these extracellular RNAs (exRNAs) revealed that they are made up both sRNAs and long non-coding RNAs (lncRNAs), including circular RNAs (circRNAs). We also found that exRNAs are highly enriched in the post-transcriptional modification N6-methyladenine (m6A). Consistent with this, we identified a putative m6A-binding protein in apoplastic wash fluids, GLYCINE-RICH RNA BINDING PROTEIN 7 (GRP7), as wells as the small RNA-binding protein ARGONAUTE2 (AGO2). These two proteins co-immunoprecipitated with each other, and with lncRNAs, including circRNAs. Mutation of GRP7 or AGO2 caused changes in both the sRNA and lncRNA content of apoplastic wash fluid, suggesting that these proteins contribute to the secretion and/or stabilization of exRNAs.
Project description:As sessile organism, plants evolved a highly complicated signaling system to cope with unfavorable and fluctuating environmental conditions. Rapid and transient Reactive Oxygen Species (ROS) burst is a common response to both biotic and abiotic stresses. Plants exposed with O3 could trigger extracellular similar ROS production through cell wall peroxidases and NPADPH oxidases, resulting in changes in the gene expression and cell death. Whereas ROS induced cell death is not simply due to its toxicity, rather due to interplay with several other signaling pathways, such as salicylic acid (SA), jasmonic acid (JA) and ethylene signaling pathways. Furthermore, the three hormones have both synergistic and antagonistic interactions, where the suppression of JA signaling by SA is the mostly studied. In addition, ethylene promotes cell death while JA has a protective role upon O3 exposure. The role of SA is more complicated; depending on the genetic background it can have either cell death promoting or protecting roles. Hence, a clean system to deliver apoplastic ROS is required to study the role of ROS apart from con-current activation of other signaling pathways. Arabidopsis thaliana offer a convenient system to study apoplastic ROS signaling due to the availability of hormone signaling or biosynthesis mutants including the JA receptor mutant coi1-16 (CORONATINE INSENSITIVE1), the essential ethylene signaling mutant ein2 (ETHYLENE INSENSITIVE2), the SA biosynthesis mutant sid2 (SALICYLIC ACID INDUCTION DEFICIENT2 also known as ISOCHORISMATE SYNTHASE1), and essential regulators in SA/JA/ethylene-induced defense response triple mutant tga2 tga5 tga6 (Clade II TGA transcription factors). Here we used a combination of transcriptome analysis, cell death assays and mutant analysis to systematically quantified the contribution of hormone signaling in relation to apoplastic ROS signaling, identified transcription factors (TFs) involved in ROS regulation and dissected the components involved in defense hormones associated cell death. Transcriptome profiling of ozone response using two arabidopsis triple mutants coi1-16 ein2 sid2 and tga2 tga5 tga6 related to Jasmonic acid, salicylic acid and ethylene signaling to identify hormone-independant apoplastic ROS signaling
Project description:Nucleosomes are barriers to transcription in vitro, however, their effects on RNA polymerase in vivo are unknown. Here we describe a simple and general strategy to comprehensively map the positions of elongating and arrested RNA Polymerase II (RNAPII) at nucleotide resolution. Our results suggest that nucleosomes present significant, context-specific barriers to RNAPII in vivo that can be tuned by the incorporation of H2A.Z. 8 sets of two replicates each of paired-end and 3 sets of two replicates each of single-end samples were sequenced and analyzed.
Project description:Across eukaryotic species, mild mitochondrial stress can have beneficial effects on the lifespan of organisms. Mitochondrial dysfunction activates an unfolded protein response (UPRmt), a stress signaling mechanism designed to ensure mitochondrial homeostasis. Perturbation of mitochondria during larval development in C. elegans not only delays aging but also maintains UPRmt signaling, suggesting an epigenetic mechanism that modulates both longevity and mitochondrial proteostasis throughout life. Here we identify the conserved histone lysine demethylases jmjd-1.2/PHF8 and jmjd-3.1/JMJD3 as positive regulators of lifespan in response to mitochondrial dysfunction across species. Reduction-of-function of the demethylases potently suppresses longevity and UPRmt induction while gain-of-function is sufficient to extend lifespan in an UPRmt-dependent manner. A systems genetics approach in the BXD mouse reference population further indicated conserved roles of the mammalian orthologs in longevity and UPRmt signaling. These findings illustrate an evolutionary conserved epigenetic mechanism that determines the rate of aging downstream of mitochondrial perturbations.
Project description:In order to identify the key factors that are crucial for non-host resistance against Bgh and are secreted depending on SYP4-mediated membrane trafficking, we have performed apoplastic fluid preparation of a series of mutants defective in the SYP4 pathway. This project aims to identify proteomic profiles of these apoplastic fluids.