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
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).
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 1)
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:Abscission is a developmental process that sheds organs in response to developmental and environmental cues. Abscission involves cell separation between two neighboring cell types in the abscission zone (AZ), residuum cells (RECs) and secession cells (SECs). However, the regulatory mechanisms for spatial determination governing cell separation are poorly understood. BREVIPEDICELLUS (BP) is one of the key transcription factors regulating the AZ cell size and number. To identify molecular components of abscission, we performed a genetic screen using a weak complementation line of bp-3 carrying activation T-DNA tagging. We identified an ebp1 (enhancer of bp1) mutant displaying delayed floral organ abscission. The ebp1 mutants show concaved surface in SECs and abnormally stacked cells on the top of RECs, in contrast to the precisely separated surface in WT. Molecular and histological analyses revealed that the transcriptional programming during cell differentiation in the AZ is compromised in the ebp1 mutant, where SECs of the ebp1 mutant appear to acquire REC-like activities, including cuticle formation and superoxide production. Here we present that SEPARATION AFFECTING RNA-BINDING PROTEIN1 (SARP1) is up-regulated in ebp1 and plays a role in the establishment of the cell separation layer during floral organ abscission in Arabidopsis.
