Functional genomic approaches to understanding abscission activation in citrus
Tadeo FR., Agustí J., Merelo P., Cercós M., Terol J., Domingo C., Talón M.
Abscission events in citrus allow the detachment of entire organs, both vegetative (buds, leaves) and reproductive (flowers, ovaries, fruitlets, mature fruits). This is achieved by the modification of cellular adhesion in a discrete group of specialized cells differentiated in predictable positions, known as abscission zones (AZs). Thus, abscission facilitates several key processes for citrus biology that, in an agricultural context, represent a major limiting factor for crop yield. In this regard, understanding the regulation of abscission is an important item for the citrus fruit industry. Several functional genomic approaches are currently being used to gain insights into the regulation of citrus abscission and to provide potential candidate genes for further biotechnological applications. These include: (a) the development of an expressed sequence tag (EST) dataset from abscission activated AZs and the analysis of ESTs distribution in organs to reveal AZ-preferential gene expression during abscission activation, (b) comparative transcriptomic analysis using cDNA microarrays and laser microdissected tissues (AZ cells, petiole and fruit rind cells flanking AZs), and (c) functional characterization of putative abscission-associated citrus genes in Arabidopsis thaliana and rice (Oryza sativa).