ABSTRACT: INFLORESCENCE DEFICIENT IN ABSCISSION (IDA) and its receptors HAE/HSL2 are required for cell expansion and cell separation during floral organ abscission in Arabidopsis thaliana (part 1)
Project description:Plants have the ability to shed organs that are no longer in use. In Arabidopsis thaliana abscission of floral organs involves cell wall remodeling and cell expansion prior to cell wall dissolution. IDA encodes a secreted peptide that signals through the leucine-rich repeat receptor-like kinases (LRR-RLKs) HAESA (HAE) (At4g28490) and HASEA-LIKE2 (HSL2) (At5g65710). Arabidopsis thaliana (ecotype Colombia-0) plants were kept in growth chambers with a 16/8 h (light/dark) photoperiod at 22 M-BM-0C, and 100 mE m-2 s-1 light intensity. 4 biological replicates were prepared from each sample, each containing abscission zone regions of siliques position 4 to 8 (when counting from the flowe at anthesis at the top of the inflorescence) from plants with at least 20 siliques. Differences in transcriptional responses were measured by comparing genes expression in abscission zones of hae hsl2 plants (SALK_021905 x SALK_030520) against abscission zones from control plants.
Project description:Plants have the ability to shed organs that are no longer in use. In Arabidopsis thaliana abscission of floral organs involves cell wall remodeling and cell expansion prior to cell wall dissolution. IDA encodes a secreted peptide that signals through the leucine-rich repeat receptor-like kinases (LRR-RLKs) HAESA (HAE) (At4g28490) and HASEA-LIKE2 (HSL2) (At5g65710). Arabidopsis thaliana (ecotype Colombia-0) plants were kept in growth chambers with a 16/8 h (light/dark) photoperiod at 22 M-BM-0C, and 100 mE m-2 s-1 light intensity. 4 biological replicates were prepared from each sample, each containing abscission zone regions of siliques position 4 to 8 (when counting from the flowe at anthesis at the top of the inflorescence) from plants with at least 20 siliques. Differences in transcriptional responses were measured by comparing genes expression in abscission zones of ida-2 plants (SALK_133209) against abscission zones from control plants.
Project description:Plants have the ability to shed organs that are no longer in use. In Arabidopsis thaliana abscission of floral organs involves cell wall remodeling and cell expansion prior to cell wall dissolution. IDA encodes a secreted peptide that signals through the leucine-rich repeat receptor-like kinases (LRR-RLKs) HAESA (HAE) (At4g28490) and HASEA-LIKE2 (HSL2) (At5g65710).
Project description:Plants have the ability to shed organs that are no longer in use. In Arabidopsis thaliana abscission of floral organs involves cell wall remodeling and cell expansion prior to cell wall dissolution. IDA encodes a secreted peptide that signals through the leucine-rich repeat receptor-like kinases (LRR-RLKs) HAESA (HAE) (At4g28490) and HASEA-LIKE2 (HSL2) (At5g65710).
2013-12-30 | GSE48106 | GEO
Project description:INFLORESCENCE DEFICIENT IN ABSCISSION (IDA) and its receptors HAE/HSL2 are required for cell expansion and cell separation during floral organ abscission in Arabidopsis thaliana
Project description:The receptor-like protein kinases encoded by HAESA (HAE) and HAESA-LIKE 2 (HSL2) are essential for floral organ abscission in Arabidopsis thaliana and the double hae hsl2 mutant fails to abscise. Expression of HAE and HSL2 is specific to Abscission Zone (AZ) cells and is higher in stage 15 flowers than in earlier developmental stages. By stage 16 floral organs have begun to abscise, suggesting that HAE HSL2 are most active in stage 15 flowers. Samples were enriched for AZ RNA by isolating RNA from flower receptacles, the region from the base of the flower to slightly above the base of attachment of the sepals, petals, and stamen. RNA-seq was then used to analyze and compare the transcriptomes of wild type and hae-3 hsl2-3 mutants. 2034 genes were differentially expressed with a False Discovery Rate adjusted p < 0.05, of which 349 genes 2 fold or greater change. Of these 349, 277 were lower in the mutant and 72 were higher. Differentially expressed genes with lower expression were enriched for hydrolytic enzymes, cell-wall modifying enzymes, and defense related genes. This suggests that HAE HSL2 signaling regulates gene expression of enzymes necessary for abscission.
Project description:The receptor-like protein kinases encoded by HAESA (HAE) and HAESA-LIKE 2 (HSL2) are essential for floral organ abscission in Arabidopsis thaliana and the double hae hsl2 mutant fails to abscise. Expression of HAE and HSL2 is specific to Abscission Zone (AZ) cells and is higher in stage 15 flowers than in earlier developmental stages. By stage 16 floral organs have begun to abscise, suggesting that HAE HSL2 are most active in stage 15 flowers. Samples were enriched for AZ RNA by isolating RNA from flower receptacles, the region from the base of the flower to slightly above the base of attachment of the sepals, petals, and stamen. RNA-seq was then used to analyze and compare the transcriptomes of wild type and hae-3 hsl2-3 mutants. 2034 genes were differentially expressed with a False Discovery Rate adjusted p < 0.05, of which 349 genes 2 fold or greater change. Of these 349, 277 were lower in the mutant and 72 were higher. Differentially expressed genes with lower expression were enriched for hydrolytic enzymes, cell-wall modifying enzymes, and defense related genes. This suggests that HAE HSL2 signaling regulates gene expression of enzymes necessary for abscission. 6 samples were sequenced, 3 biological replicates of Col-0 wild type and 3 biological replicates of the hae-3 hsl2-3 double mutant. Samples were barcoded and all 6 samples multiplexed and sequenced on 3 lanes, each lane on a separate flow cell, of an Illumina HiSeq 2000.
Project description:INFLORESCENCE DEFICIENT IN ABSCISSION (IDA) and its receptors HAE/HSL2 are required for cell expansion and cell separation during floral organ abscission in Arabidopsis thaliana (part 2)
Project description:Plant inflorescence meristems and floral meristems possess specific boundary domains that result in floral organ separation, and in proper numbers of floral organs. HANABA TARANU (HAN) encodes a boundary-expressing GATA type zinc finger transcription factor that regulates shoot apical meristem organization, cell division and flower development in Arabidopsis, but the underlying mechanism remains unclear. Through time-course whole genome oligonucleotide microarray analyses following transient overexpression of HAN, we find that HAN represses hundreds of genes, especially genes involved in hormone responses and floral organ regulation. Transient overexpression of HAN also causes the repression of HAN itself and three other HAN family genes: HANL2 (HAN-LIKE2), GNC (GATA, NITRATE-INDUCIBLE, CARBON-METABOLISM-INVOLVED) and GNL (GNC LIKE), forming a negative regulatory feedback loop. Double- and triple-mutant strains of han with hanl2, gnc and gnl show synergistic effects on sepal fusion, petal number, and silique length, and embryo development, as well as carpelloid stamens. Transcripts of HANL2, GNC and GNL have similar accumulation patterns, specifically in petals, stamens, carpels and inflorescence meristems, which are partially overlapping with the expression pattern of HAN, suggesting that HAN and HAN family genes share redundant functions during flower development. We further show by yeast two hybrid assays that HAN can homodimerize as well as heterodimerize with other HAN family proteins. Chromatin-immunoprecipitation analyses indicate that HAN directly binds to its own promoter and the promoter of GNC in vivo. These findings, together with the fact that constitutive overexpression of HAN has an even stronger phenotype than a loss of function mutation, support the hypothesis that HAN may function as a key repressor that regulates floral development via intricate regulatory networks involving genes in the GATA3 family, hormone actions and floral organ specification.
