Project description:The growth and shape of plants is mainly defined by the properties of their cell walls, which dynamically adapt to internal and external cues. Therefore, the cell wall is under constant surveillance to relay feedback information to the cell interior. However, very little is known about how cell wall signaling is integrated with intracellular growth regulation. Here, we have identified a receptor-like protein, RLP44, which conveys information from the cell wall to the brassinosteroid hormone signaling pathway by interacting with the regulatory receptor-like kinase BAK1. This conditional RLP44-mediated signaling activation is required for normal development and stress responses, requires functional brassinosteroid receptor, but is partially independent of the hormone ligand. We sought to identify transcriptional changes in the PMEIox transformant in which an altered pectin modification leads to an induction of the brassinosteroid signalling pathway. In addition we determined which fraction of these expression changes was reverted in the cnu1 and cnu2 suppressor mutants of PMEIox, respectively. Complete transcriptome analysis was performed on Col-0 wild-type as well as the PMEIox transformant and the cnu1 and cnu2 suppressor mutant seedlings grown in the dark for four days. 3 Biological replicates of etiolated seedlings grown for 4 days in the dark were harvested on successive weeks.
Project description:We characterized the global response of plants carrying a mitochondrial dysfunction induced by the expression of the unedited form of the ATP synthase 9 subunit. The u-ATP9 transgene driven by A9 and Apetala3 promoters induce mitochondrial dysfunction revealed by a decrease in both oxygen uptake and ATP levels, with an increase in ROS and a concomitant oxidative stress response. The transcriptome analysis of young Arabidopsis flowers, validated by RT-PCR and enzymatic or functional tests, show dramatic changes in u-ATP9 plants. Both lines present a modification in the expression of several genes involved in carbon, lipid and cell wall metabolism, suggesting that an important metabolic readjustment occurs in plants with a mitochondrial dysfunction. Interestingly, transcript levels involved in mitochondrial biogenesis, protein synthesis, and degradation are affected. Moreover, several mRNA levels for transcription factors and DNA binding proteins were also changed. Some of them are involved in stress and hormone response, suggesting that several signaling pathways overlap. Indeed, the transcriptome data reveal that the mitochondrial dysfunction dramatically alters genes involved in signaling pathways, including those involved in ethylene, absicic acid and auxin signal transduction. Our data suggest that the mitochondrial dysfunction model used in this rapport may be useful to uncover the retrograde signaling mechanism between the nucleus and mitochondria in plant cells.
Project description:The growth and shape of plants is mainly defined by the properties of their cell walls, which dynamically adapt to internal and external cues. Therefore, the cell wall is under constant surveillance to relay feedback information to the cell interior. However, very little is known about how cell wall signaling is integrated with intracellular growth regulation. Here, we have identified a receptor-like protein, RLP44, which conveys information from the cell wall to the brassinosteroid hormone signaling pathway by interacting with the regulatory receptor-like kinase BAK1. This conditional RLP44-mediated signaling activation is required for normal development and stress responses, requires functional brassinosteroid receptor, but is partially independent of the hormone ligand. We sought to identify transcriptional changes in the PMEIox transformant in which an altered pectin modification leads to an induction of the brassinosteroid signalling pathway. In addition we determined which fraction of these expression changes was reverted in the cnu1 and cnu2 suppressor mutants of PMEIox, respectively. Complete transcriptome analysis was performed on Col-0 wild-type as well as the PMEIox transformant and the cnu1 and cnu2 suppressor mutant seedlings grown in the dark for four days.
Project description:Heterotrimeric G proteins mediate crucial and diverse signaling pathways in eukaryotes. To gain insights into the regulatory modes of the G protein and the co-regulatory modes of the G protein and the stress hormone abscisic acid (ABA), we generated and analyzed gene expression in G protein subunit single and double mutants of the model plant Arabidopsis thaliana. Through a Boolean modeling approach, our analysis reveals novel modes of heterotrimeric G protein action. Keywords: transcriptome analysis; G protein subunit mutants; abscisic acid (ABA)
Project description:Plants need to be able to respond to changes quickly due to the inability of a plant to change location. Hormones within the plant signal for these transcriptional changes that will affect the plant's ability to survive. Strigolactone is a plant hormone that was more recently discovered so has a less detailed understanding of what genes it regulates, compared to other plant hormones. First published in Brewer et al 2016, PNAS We used microarrays to determine transcriptional responses in strigolactone mutants and in wild-type plants with various physiological treatment which affect hormone levels over 24 hours.
Project description:In this study, we describe an antibody-based approach to enrich ubiquitinated peptides from vegetative tissues for detection via peptide mass spectrometry. This enrichment method can be coupled with isobaric labeling to enable quantification from up to 18-multiplexed samples. This approach identified 19,740 ubiquitinated lysine sites arising from 5,936 proteins in Arabidopsis primary roots, seedlings and rosette leaves. Gene Ontology analysis indicated that ubiquitinated proteins are associated with numerous biological processes including hormone signaling, plant defense, protein homeostasis, and metabolism. Proteins with altered abundance and ubiquitination state in roots upon bortezomib treatment included transporters, adaptors, and transcription factors.
Project description:The structure and composition of plant cell walls are modified to accommodate the needs of the cell and in response to environmental stimuli. Growth, development, and defense may demand potentially conflicting functional cell wall requirements, and thus modifications of the cell wall are tightly controlled in an adaptive manner. These modifications are mediated by a dedicated cell wall integrity (CWI) maintenance mechanism. We investigated the responses to cell wall damage (CWD) that compromise CWI and the underlying mechanisms in Arabidopsis thaliana. Inhibitor- and enzyme-triggered CWD induced similar, turgor-sensitive stress responses. Genetic analysis showed that the receptor-like kinase (RLK) FEI2 and the plasma membrane-localized mechano-sensitive Ca2+- channel MCA1 function downstream of the RLK THE1 in CWD perception. Phenotypic clustering with 27 genotypes identified a core group of RLKs and ion channels required for activation of CWD responses. In contrast, the responses were repressed by pattern-triggered immunity (PTI) signaling components including the receptors for plant elicitor peptides (AtPeps) PEPR1 and PEPR2 (PEPR1/2). Application of AtPep1 and AtPep3 repressed CWD-induced phytohormone accumulation in a concentration dependent manner. CWD induced the expression of both PROPEP1 and PROPEP3 as well as the release of a PROPEP3 fusion protein into the growth medium. These results suggest that AtPep-mediated signaling suppresses CWD-induced defense responses. If key PTI signaling elements acting downstream of PEPR1/2 are dysfunctional, suppression of CWD-induced responses is alleviated, thus compensating for the impairment.