Expression profiling of tomato pre-abscission pedicels

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.