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)
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ABSTRACT: 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). 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:We have implemented an integrated Systems Biology approach to analyze overall transcriptomic reprogramming and systems level defense responses in the model plant Arabidopsis thaliana during an insect (Brevicoryne brassicae) and a bacterial (Pseudomonas syringae pv. tomato strain DC3000) attack. The main aim of this study was to identify the attacker-specific and general defense response signatures in the model plant Arabidopsis thaliana while attacked by phloem feeding aphids or pathogenic bacteria. Defense responses and networks, unique and specific for aphid or Pseudomonas stresses were identified. Our analysis revealed a probable link between biotic stress and microRNAs in Arabidopsis and thus opened up a new direction to conduct large-scale targeted experiments to explore detailed regulatory links among them. The presented results provide a first comprehensive understanding of Arabidopsis - B. brassicae and Arabidopsis - P. syringae interactions at a systems biology level. Arabidopsis thaliana (ecotype Colombia-0) seeds were grown in 6-cm-diameter pots filled with a sterile soil mix (1.0 part soil and 0.5 part horticultural perlite), 3 plants per pot. Plants were kept in growth chambers VM-CM-6tsch VB 1514 (VM-CM-6tsch Industrietechnik GmbH, Germany) under the following conditions: a 8/16 h (light/dark) photoperiod at 22M-BM-0C/18M-BM-0C, 40%/70% relative humidity, and 70/0 M-NM-<mol m-2s-1 light intensity. After 32 days plants had 8 fully developed leaves. Each plant was infested with 32 wingless aphids [Brevicoryne Brassicae] (4 per leaf), which were transferred to leaves with a fine paintbrush. Infested plants and aphid-free controls were kept in plexiglass cylinders. Plants were harvested 72 h after infestation between the 6th and 8th hour of the light photoperiod. Four biological replicates were prepared from aphid infested and control plants, each sampled from 15 individual plants. Whole rosettes were cut at the hypocotyls and aphids were removed by washing with Milli-Q-filtered water. Differences in transcriptional responses were measured by comparing genes expression of aphid infested plants against non-infested 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:Organ abscission is a general activity found in plants and its regulation is an important agronomical concern because the trait directly affects the harvesting efficiency of fruits or grains and the yields. Generally, abscission takes place at a specialized cell layer, which is called abscission zones (AZs). So far, investigations on organ abscission have been focused mainly on the cell activities during organ detachment. By contrast, little attention has been paid to the properties of AZ cells at the pre-abscission stage. The pre-abscission cells are at a turning point for initiating abscission; until an abscission initiating signal is provided, the AZ cells keep their physiological state, while once the signal occurs, the cells immediately change their state into the onset of abscission. In this study, to screen the genes involved in the regulation of abscission at the pre-abscission state, we investigated the gene expression profiles of tomato flower pedicels at anthesis. The screening revealed many genes that characterize cell identities in each pedicel region.
Project description:We have implemented an integrated Systems Biology approach to analyze overall transcriptomic reprogramming and systems level defense responses in the model plant Arabidopsis thaliana during an insect (Brevicoryne brassicae) and a bacterial (Pseudomonas syringae pv. tomato strain DC3000) attack. The main aim of this study was to identify the attacker-specific and general defense response signatures in the model plant Arabidopsis thaliana while attacked by phloem feeding aphids or pathogenic bacteria. Defense responses and networks, unique and specific for aphid or Pseudomonas stresses were identified. Our analysis revealed a probable link between biotic stress and microRNAs in Arabidopsis and thus opened up a new direction to conduct large-scale targeted experiments to explore detailed regulatory links among them. The presented results provide a first comprehensive understanding of Arabidopsis - B. brassicae and Arabidopsis - P. syringae interactions at a systems biology level. Arabidopsis thaliana (ecotype Colombia-0) seeds were sown into 6-cm-diameter pots filled with a sterile soil mix (1.0 part soil and 0.5 part horticultural perlite). Plants were kept in growth chambers VM-CM-6tsch VB 1514 (VM-CM-6tch Industrietechnik GmbH, Germany) with a 16/8 h (light/dark) photoperiod at 22/18 M-BM-0C, 40/70% relative humidity, and 70/0 mmol m-2 s-1 light intensity. The Pseudomonas syringae pv. tomato strain DC3000 culture was grown overnight in 10 ml of Kings B solution supplemented with antibiotics rifampicin (50 M-NM-<g mlM-bM-^HM-^R1) and kanamycin (25 M-NM-<g mlM-bM-^HM-^R1). Overnight culture was washed once in 10 mM MgCl2 and final cell densities were adjusted to approximately 0.20 at 600 nm (approximately 1.5 M-CM-^W 108 cfu mlM-bM-^HM-^R1) in 10 mM MgCl2. Plants were mock-challenged with 10 mM MgCl2 or inoculated with DC3000 strain, 3-4 leaves were infiltrated on the abaxial surface with a needleless 1-ml syringe.Whole rosettes were cut at the hypocotyls and harvested from Pseudomonas infested and mock-infected plants after 72 hours treatment. 4 biological replicates were prepared from each treatment, each containing rosettes from 15 individual plants. Differences in transcriptional responses were measured by comparing genes expression of Pseudomonas infected plants against mock-infected control plants.
Project description:Organ abscission is a general activity found in plants and its regulation is an important agronomical concern because the trait directly affects the harvesting efficiency of fruits or grains and the yields. Generally, abscission takes place at a specialized cell layer, which is called abscission zones (AZs). So far, investigations on organ abscission have been focused mainly on the cell activities during organ detachment. By contrast, little attention has been paid to the properties of AZ cells at the pre-abscission stage. The pre-abscission cells are at a turning point for initiating abscission; until an abscission initiating signal is provided, the AZ cells keep their physiological state, while once the signal occurs, the cells immediately change their state into the onset of abscission. In this study, to screen the genes involved in the regulation of abscission at the pre-abscission state, we investigated the gene expression profiles of tomato flower pedicels at anthesis. The screening revealed many genes that characterize cell identities in each pedicel region. We harvested tomato flower pedicels at the anthesis stage and divided them into three parts: the abscission zone (AZ) and the flanking proximal- (Prox) and distal- (Dis) regions. RNA was isolated and subjected to DNA microarray analyses. Experiments were performed three times with independently prepared samples.
Project description:Abscission is a cell separation process that takes place in particular positions of the plant body named abscission zones. In citrus, maturing fruits are shed through the calix abscission zone, which is composed by 10-15 cell layers located at the boundary between the calyx button and the fruit rind. In order to gain further insight into the molecular mechanisms involved in citrus fruit abscission, we used laser microdissection combined with microarray analysis to compare the global expression profiles of calyx abscission zone cells and adjacent fruit rind cells (control cells) at 0, 12 and 24 hours after the activation of the process with ethylene. Thus, this study allowed identifying a set of abscission zone-specifically expressed genes potentially involved in citrus fruit abscission.
Project description:The aim of this study is to assess the global transcriptome changes during the shedding of the flower, which normally takes around 6 or 7 days. We selected four time points (from day 0 to day 6) and three different tissues within the flower bud; distal, abscission and proximal zones with three biological replicates. RNA extraction, library prep and paired end sequencing was performed. Our special interest is try to describe the changes in the abscission zone and the two adjacent tissues in order to get a whole picture of the shedding process. We performed a de novo assembly by Trinity and detected the transcripts and expression changes across spatial and temporal comparisons.