Unknown,Transcriptomics,Genomics,Proteomics

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Arabidopsis thaliana Growth is Negatively Regulated by the Class III Peroxidase AtPrx71 during Development and in Response to Cell Wall Damage

ABSTRACT: The cell wall is a crucial structure in plant cells, and modifications in its composition often have a major impact on growth and development. However, the molecular mechanisms responsible for the negative effects of cell wall alterations on plant growth are largely unknown. It was previously shown that a reduction in the levels of de-esterified homogalacturonan, a major pectin component of cell walls, in Arabidopsis thaliana plants expressing a fungal polygalacturonase or mutated in the QUASIMODO2 gene (qua2-1 plants), cause severe growth defects. Here we show that the class III peroxidase AtPrx71 is strongly up-regulated in these plants, as well as in response to alterations of other wall structural components, including treatments the cellulose synthase inhibitor isoxaben. Analysis of atprx71 loss-of-function mutants and of plants overexpressing AtPrx71 indicates that this gene negatively affects Arabidopsis growth at different stages of development. Furthermore, lack of AtPrx71 partially suppresses the dwarf phenotype of qua2-1, suggesting that this protein contributes to the growth defects observed in plants undergoing cell wall damage. AtPrx71 appears to promote the production of reactive oxygen species in qua2-1 plants, as well as in plants treated with isoxaben. We propose that production of reactive oxygen species mediated by AtPrx71 negatively regulates Arabidopsis growth both during physiological development and in response to loss of cell wall integrity. Transcriptional profiling of Arabidopsis thaliana wt control plants and PG57 and PG26 transgenic lines overexpressing the AtPrx71 gene.

ORGANISM(S): Arabidopsis thaliana

SUBMITTER: Alberto Ferrarini

PROVIDER: E-GEOD-66980 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

The Arabidopsis Class III Peroxidase AtPRX71 Negatively Regulates Growth under Physiological Conditions and in Response to Cell Wall Damage.

Raggi Sara S Ferrarini Alberto A Delledonne Massimo M Dunand Christophe C Ranocha Philippe P De Lorenzo Giulia G Cervone Felice F Ferrari Simone S

Plant physiology 20151014 4

The structure of the cell wall has a major impact on plant growth and development, and alteration of cell wall structural components is often detrimental to biomass production. However, the molecular mechanisms responsible for these negative effects are largely unknown. Arabidopsis (Arabidopsis thaliana) plants with altered pectin composition because of either the expression of the Aspergillus niger polygalacturonase II (AnPGII; 35S:AnPGII plants) or a mutation in the QUASIMODO2 (QUA2) gene that ...[more]

PMID: 26468518

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Project description:ra03-04_elongation_isoxaben - isoxaben treatment - 1. Study the molecular basis of the growth acceleration observed in hypocotyl cells. We previously have observed that cell elongation takes place in two distinct phases (Refregier et al., 2004). A slow growth phase during which a thick polylamellated wall is deposited and a rapid growth phase during which cell wall polymers are extensively remodelled. In dark-grown hypocotyls the slow growth phase takes place during the first 48h after seed-imbibition synchronously in all cells. At 48h after imbibition, cells at the basis of the hypocotyl undergo a growth acceleration, this acceleration follows an acropetal gradient along the hypocotyl. In this experiment, we investigated the changes in transcript abundance that accompany this sudden increase in growth rate. 2. Study the feed-back mechanisms involved in the coordination between cellulose synthesis and the cell elongation. The inhibition of cellulose using chemical inhibitors also inhibits cell elongation. In the same study (Refregier et al., 2004), we have observed that the effect of the cellulose synthesis inhibitor isoxaben on cell elongation is different dependent on the growth stage. When applied during the slow growth phase, cells continue to elongate slowly and do not show the growth acceleration at 48h after imbibition. Surprisingly, when applied after the growth acceleration, isoxaben does not inhibit subsequent growth. In this study we compared the effects of isoxaben on the transcript profiles before and after the growth acceleration. This should inform us about the response of the hypocotyl cells to the inhibition of cellulose and should provide insights into the molecular events that underly the observed coupling between cellulose synthesis and cell elongation. - 1- 45 hours, transfer to medium +/-isoxaben, harvest at 48 hours: comparison 48 hours + /- isoxaben. 2- 52 hours, transfer on + /-isoxaben, harvest 55 hours: comparison 55 hours + /-isoxaben (after transition: inhibition synthesis of cellulose, no inhibition of cellular elongation). Keywords: treated vs untreated comparison

Project description:We used the flu mutant of Arabidopsis and a transgenic line that overexpresses the thylakoid-bound ascorbate peroxidase (tAPX) to address the interactions between different reactive oxygen species (ROS) signaling pathways. The conditional flu mutant of Arabidopsis accumulates excess protochlorophyllide in the dark within chloroplast membranes that upon illumination acts as a photosensitizer and generates singlet oxygen (1O2). Immediately after the release of singlet oxygen rapid changes in nuclear gene expression occur. Distinct sets of genes were activated that were different from those induced by other reactive oxygen species, superoxide or hydrogen peroxide (H2O2), suggesting that different types of active oxygen species activate distinct signaling pathways. It was not known whether the pathways operate separately or interact with each other. We have addressed this problem by modulating noninvasively the level of H2O2 in plastids by means of a transgenic line that overexpresses the thylakoid-bound ascorbate peroxidase (tAPX, line 14/2 PMID: 15165186). In the flu mutant overexpressing tAPX, the expression of most of the nuclear genes that were rapidly activated after the release of 1O2 was significantly higher in flu plants overexpressing tAPX, whereas in wild-type plants, overexpression of tAPX had only a very minor impact on nuclear gene expression. The results suggest that H2O2 antagonizes the 1O2-mediated signaling of stress responses as seen in the flu mutant. This cross-talk between H2O2- and 1O2-dependent signaling pathways might contribute to the overall stability and robustness of wild-type plants exposed to adverse environmental stress conditions. Experiment Overall Design: Arabidopsis thaliana rosette leaves were harvested after 2 h of reillumination following a 8h dark period for RNA extraction and hybridization on Affymetrix ATH1 microarrays. The entire experiment was performed six times, providing independent biological replicates. For each of the six experiments, all four lines, wild-type, thylakoidal ascorbate peroxidase overexpressor (over tAPX, line 14/2), flu mutant and flu plants overexpressing thylakoidal ascorbate peroxidase were grown for 3 weeks under continuous light at 90 mmol. m-2 . s-1, transferred to the dark for 8 h, and reilluminated for 120 min before the rosette leaves of at least 10 plants per line were harvested. Total RNAs from three separate biological experiments were pooled (= 1 biological rep.) for the preparation of cDNA and the subsequent synthesis of biotin-labeled complementary RNA as recommended by Affymetrix.

Dataset Information

Arabidopsis thaliana Growth is Negatively Regulated by the Class III Peroxidase AtPrx71 during Development and in Response to Cell Wall Damage

Publications

The Arabidopsis Class III Peroxidase AtPRX71 Negatively Regulates Growth under Physiological Conditions and in Response to Cell Wall Damage.

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