Ethylene-induced differential gene expression during abscission of citrus leaves
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2008Cita bibliográfica
Agustí, J., Merelo, P., Cercós, M., Tadeo, F. R., & Talón, M. (2008). Ethylene-induced differential gene expression during abscission of citrus leaves. Journal of experimental botany, 59(10), 2717-2733.Abstract
The main objective of this work was to identify and
classify genes involved in the process of leaf abscission
in Clementina de Nules (Citrus clementina Hort.
Ex Tan.). A 7 K unigene citrus cDNA microarray
containing 12 K spots was used to characterize the
transcriptome of the ethylene-induced abscission process
in laminar abscission zone-enriched tissues and
the petiole of debladed leaf explants. In these conditions,
ethylene induced 100% leaf explant abscission
in 72 h while, in air-treated samples, the abscission
period started later and took 240 h. Gene expression
monitored during the first 36 h of ethylene treatment
showed that out of the 12 672 cDNA microarray
probes, ethylene differentially induced 725 probes
distributed as follows: 216 (29.8%) probes in the
laminar abscission zone and 509 (70.2%) in the petiole.
Functional MIPS classification and manual annotation
of differentially expressed genes highlighted key processes
regulating the activation and progress of the
cell separation that brings about abscission. These
included cell-wall modification, lipid transport, protein
biosynthesis and degradation, and differential activation
of signal transduction and transcription control
pathways. Expression data associated with the petiole
indicated the occurrence of a double defensive strategy
mediated by the activation of a biochemical programme
including scavenging ROS, defence and PR
genes, and a physical response mostly based on lignin
biosynthesis and deposition. This work identifies new
genes probably involved in the onset and development
of the leaf abscission process and suggests a different
but co-ordinated and complementary role for the
laminar abscission zone and the petiole during the
process of abscission.