Project description:In Arabidopsis, jasmonate is required for stamen and pollen maturation. Mutants deficient in jasmonate synthesis, such as opr3, are male-sterile but become fertile when jasmonate is applied to developing flower buds. We have used ATH1 oligonucleotide arrays to follow gene expression in opr3 stamens for 22 hours following jasmonate treatment. In these experiments, a total of 821 genes were specifically induced by jasmonate and 480 repressed. Comparisons with data from previous studies indicate that these genes constitute a stamen-specific jasmonate transcriptome, with a large proportion (70%) of the genes expressed in the sporophytic tissue but not in the pollen. Bioinformatics tools allowed us to associate many of the induced genes with metabolic pathways that are likely up-regulated during jasmonate-induced maturation. Our pathway analysis led to the identification of specific genes within larger families of homologues that apparently encode stamen-specific isozymes. Extensive additional analysis of our dataset identified 13 transcription factors that may be key regulators of the stamen maturation processes triggered by jasmonate. Two of these transcription factors, MYB21 and MYB24, are the only members of subgroup 19 of the R2R3 family of MYB proteins. A myb21 mutant obtained by reverse genetics exhibited shorter anther filaments, delayed anther dehiscence and greatly reduced male fertility. A myb24 mutant was phenotypically wild type, but production of a myb21 myb24 double mutant indicated that introduction of the myb24 mutation exacerbated all three aspects of the myb21 phenotype. Exogenous jasmonate could not restore fertility to myb21 or myb21 myb24 mutant plants. Together with the data from transcriptional profiling, these results indicate that MYB21 and MYB24 are induced by jasmonate and mediate important aspects of the jasmonate response during stamen development. Keywords: Time course analysis
Project description:This study evaluates the transcriptome of Arabidopsis thaliana seedlings (Col-0 ecotype) treated with methyl jasmonate (MeJA) or with the salicylic acid analog benzothiadiazole (BTH).
Project description:In Arabidopsis, jasmonate is required for stamen and pollen maturation. Mutants deficient in jasmonate synthesis, such as opr3, are male-sterile but become fertile when jasmonate is applied to developing flower buds. We have used ATH1 oligonucleotide arrays to follow gene expression in opr3 stamens for 22 hours following jasmonate treatment. In these experiments, a total of 821 genes were specifically induced by jasmonate and 480 repressed. Comparisons with data from previous studies indicate that these genes constitute a stamen-specific jasmonate transcriptome, with a large proportion (70%) of the genes expressed in the sporophytic tissue but not in the pollen. Bioinformatics tools allowed us to associate many of the induced genes with metabolic pathways that are likely up-regulated during jasmonate-induced maturation. Our pathway analysis led to the identification of specific genes within larger families of homologues that apparently encode stamen-specific isozymes. Extensive additional analysis of our dataset identified 13 transcription factors that may be key regulators of the stamen maturation processes triggered by jasmonate. Two of these transcription factors, MYB21 and MYB24, are the only members of subgroup 19 of the R2R3 family of MYB proteins. A myb21 mutant obtained by reverse genetics exhibited shorter anther filaments, delayed anther dehiscence and greatly reduced male fertility. A myb24 mutant was phenotypically wild type, but production of a myb21Â myb24 double mutant indicated that introduction of the myb24 mutation exacerbated all three aspects of the myb21 phenotype. Exogenous jasmonate could not restore fertility to myb21 or myb21Â myb24 mutant plants. Together with the data from transcriptional profiling, these results indicate that MYB21 and MYB24 are induced by jasmonate and mediate important aspects of the jasmonate response during stamen development. Experiment Overall Design: Three replicates for opr3 at each time point of 0 hour, 30 minutes, 2 hours, 8 hours and 22 hourss of either JA or OPDA treatment. One replicate of wild-type stamens. <br><br>Note that data files GSM106833.txt and GSM106907.txt as downloaded from GEO are identical.
Project description:12-oxo-phytodienoic acid (OPDA) and phytoprostane A1 (PPA1) are cyclopentenone oxylipins that are formed via the enzymatic jasmonate pathway and a nonenzymatic, free radical–catalyzed pathway, respectively. Both types of cyclopentenone oxylipins induce the expression of genes related to detoxification, stress responses, and secondary metabolism, a profile clearly distinct from that of the cyclopentanone jasmonic acid. To investigate the role of TGA transcriction factors in oxylipin responses, the regulation of gene expression by OPDA and PPA1 defective in the expression of TGA2, TGA5, and TGA6 was analyzed using Affymetrix ATH1 chips. Keywords: Arabidopsis tga2-5-6 mutant, Oxylipin treatment, ATH1 Chip
Project description:This study evaluates the transcriptome of Arabidopsis thaliana seedlings chronically exposed to the hormone Methyl Jasmonate (MeJA) or to the bacterial elicitor flg22 (a 22-amino acid peptide from flagellin). Treatments were performed under high and low phosphate availability using wild-type Col-0 plants and the phr1 phl1 mutant.
Project description:12-Oxo-phytodienoic acid (OPDA) and several phytoprostanes are structurally related cyclopentenone oxylipins that can be formed via the enzymatic jasmonate pathway and a non-enzymatic, free radical-catalyzed pathway, respectively. To elucidate the biological activities of phytoprostanes in comparison to OPDA as well as the metabolism we performed genome-wide expression analysis. Keywords: mixotrophic Arabidopsis cell culture, ATH1 Chip
Project description:We treated Arabidopsis seedlings with chitosan and carried out a transcript profiling analysis (GeneChip microarrays) in order to identify genes and transcription factors regulated by chitosan. The results showed that jasmonate and defense responsive genes, camalexin and lignin biosynthetic genes were among genes up-regulated by chitosan. Several transcription factors are also strongly induced by chitosan. The results suggested that chitosan can be used as a strong elicitor of defense pathways.
Project description:The function of the plant hormone jasmonic acid (JA) in development of tomato flowers was analyzed with a mutant defective in JA perception (jasmonate-insensitive1-1, jai1-1). In contrast to Arabidopsis JA-insensitive plants that are male sterile, the tomato mutant jai1-1 exhibits major defects in female development resulting in female sterility. To identify putative JA-dependent regulatory components, transcriptomics was performed using isolated ovules of three different stages of flower development, from both wild type and jai1-1. Among the strongly down-regulated genes in jai1-1, one encoding a MYB transcription factor (SlMYB21) was found. Its orthologue in Arabidopsis has a crucial role in JA-regulated stamen development. SlMYB21 showed transcription factor activity in yeast, interaction with SlJAZ9 in yeast and in planta, and complemented the Arabidopsis mutant myb21-5. To analyze SlMYB21 function in tomato ovule development, CRISPR/Cas9 mutants were created and a TILLING mutant was identified, all showing female sterility and therefore corroborating a function of MYB21 in tomato ovule development. Transcriptomics from wild type, jai1-1 and myb21-2 carpels revealed processes that might be controlled by SlMYB21. The data suggest a positive regulation of JA biosynthesis by SlMYB21, but a negative regulation of the action of auxin and GA. The results demonstrate that SlMYB21 mediates at least partially the action of JA and might control the flower to fruit transition.
Project description:The function of the plant hormone jasmonic acid (JA) in development of tomato flowers was analyzed with a mutant defective in JA perception (jasmonate-insensitive1-1, jai1-1). In contrast to Arabidopsis JA-insensitive plants that are male sterile, the tomato mutant jai1-1 exhibits major defects in female development resulting in female sterility. To identify putative JA-dependent regulatory components, transcriptomics was performed using isolated ovules of three different stages of flower development, from both wild type and jai1-1. Among the strongly down-regulated genes in jai1-1, one encoding a MYB transcription factor (SlMYB21) was found. Its orthologue in Arabidopsis has a crucial role in JA-regulated stamen development. SlMYB21 showed transcription factor activity in yeast, interaction with SlJAZ9 in yeast and in planta, and complemented the Arabidopsis mutant myb21-5. To analyze SlMYB21 function in tomato ovule development, CRISPR/Cas9 mutants were created and a TILLING mutant was identified, all showing female sterility and therefore corroborating a function of MYB21 in tomato ovule development. Transcriptomics from wild type, jai1-1 and myb21-2 carpels revealed processes that might be controlled by SlMYB21. The data suggest a positive regulation of JA biosynthesis by SlMYB21, but a negative regulation of the action of auxin and GA. The results demonstrate that SlMYB21 mediates at least partially the action of JA and might control the flower to fruit transition.
Project description:Comparison of mock-treated vs. methyl jasmonate-treated (6 hours, 0.1 uM) wild type (Col-0) vs. myc2 (jin1-9) mutant Arabidopsis lines. Note: an error in the processing of the normalized data was noticed November 2008. Corrected data was reloaded 1st December 2008.