Project description:The cell wall is a defining feature of plant cells and glues cells to each other. To overcome this physical constraint, plants must process and disconnect cell wall linkages during growth and development. However, little is known about the mechanism guiding cell-cell detachment and cell wall remodeling. Here, we identify two neighboring cell types in Arabidopsis that coordinate their activities to control cell wall processing, thereby ensuring precise abscission to discard organs. One cell type produces a honeycomb structure of lignin, which acts as a mechanical ‘brace’ to localize cell wall breakdown and spatially limit abscising cells. The second cell type undergoes transdifferentiation into epidermal cells, forming protective cuticle, demonstrating de novo specification of epidermal cells, previously thought to be restricted to embryogenesis. Loss of the lignin brace leads to inadequate cuticle formation, resulting in surface barrier defects and susceptible to infection. Altogether, we show how plants precisely accomplish 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.
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:Transcription profiling of the ethylene-induced abscission process in laminar abscission zone cells and petiolar cortical cells of debladed mature citrus leaf explants. Samples taken at 24h after ethylene treatment (10 ul/l) were compared.
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: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 conducted transcriptional profiling of laser-captured stamen abscission zone cells over five developmental stages from prepollination to organ shed.