Comparative transcriptional survey between laser-microdissected cells from laminar abscission zone and petiolar cortical tissue during ethylene-promoted abscission in citrus leaves

Abstract

Background: Abscission is the cell separation process by which plants are able to shed organs. It has a great impact on the yield of most crop plants. At the same time, the process itself also constitutes an excellent model to study cell separation processes, since it occurs in concrete areas known as abscission zones (AZs) which are composed of a specific cell type. However, molecular approaches are generally hampered by the limited area and cell number constituting the AZ. Therefore, detailed studies at the resolution of cell type are of great relevance in order to accurately describe the process and to identify potential candidate genes for biotechnological applications.

Microarray Analysis of the Abscission-Related Transcriptome in the Tomato Flower Abscission Zone in Response to Auxin Depletion

“…The total number of genes affected in the AZ by flower removal and/or 1-MCP pretreatment in each cluster presented in Figure 3 The symbols of the cluster types are detailed in the legend to Figure 3 with cell wall modification functions, including EXPs (three genes), extensin (EXT4), glycosyl hydrolase (three genes), pectin methylesterase (PME; five genes), PER (11 genes), PG (three genes), and xyloglucan endotransglycosylase/hydrolase (XTH; four genes). Differential expression of genes associated with cell wall metabolism during abscission was demonstrated also during ethylene-induced abscission of Citrus leaves (Agustí et al, 2008(Agustí et al, , 2009). These included genes for two different PGs, cellulase, and two different XTHs (XTH1 and XTH2) that were overexpressed in the leaf AZ-enriched tissue (Agustí et al, 2008).…”

“…If the source of IAA is removed, the AZ becomes sensitized to the action of ethylene and abscission commences (Rubinstein and Leopold, 1963;Abeles and Rubinstein, 1964;Addicott, 1982;Sexton and Roberts, 1982;Meir et al, 2003Meir et al, , 2006. Accordingly, the activities of cell wall-degrading enzymes, including cellulase (Cel), polygalacturonase (PG), expansin (EXP), and xyloglucan endohydrolase endotransglycosylase (XET), have been shown to increase dramatically with the onset of abscission (Lashbrook et al, 1994;Kalaitzis et al, 1997;Agustí et al, 2008Agustí et al, , 2009Cai and Lashbrook, 2008;Roberts and Gonzalez-Carranza, 2009). …”

Tissue- and Cell-Type Specific Transcriptome Profiling of Expanding Tomato Fruit Provides Insights into Metabolic and Regulatory Specialization and Cuticle Formation

“…However, while this strategy has provided a degree of spatial resolution, plant material isolated by relatively crude peeling inevitably contains varying proportions of multiple pericarp cell types. A more precise alternative for isolating specific cell or tissue types is laser capture microdissection (LCM; also termed laser microdissection), which has been applied to profile gene expression in a range of vegetative plant tissues or cell types, including abscission zones, vascular bundles, parenchyma, incipient leaves, root tissues, and meristems (Cai and Lashbrook, 2008;Nelson et al, 2008;Agustí et al, 2009;Brooks et al, 2009;Jiao et al, 2009). Such studies of low abundance tissues have resulted in the identification of a relatively large number of previously unannotated genes, demonstrating the value of LCM as a tool for gene discovery.…”

Programmed Cell Death Occurs Asymmetrically during Abscission in Tomato

“…Several proteins have been shown to have a regulatory role in abscission, including potential signal molecules and receptors (Lewis et al, 2006;Cho et al, 2008;McKim et al, 2008;Stenvik et al, 2008;Liljegren et al, 2009;van Nocker, 2009). Transcriptomic analyses during abscission have identified genes that are regulated during this process (Cai and Lashbrook, 2008;Agustí et al, 2009;Meir et al, 2010).…”