The OCP3 Gene Links Drought Tolerance and Plant Immunity pp. 311-324
Authors: (Vicente Ramírez, Ana López, Javier García-Andrade, Pablo Vera, Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Universidad Politécnica de Valencia, Ciudad Politécnica de la Innovación, Valencia, Spain)
Abstract: Water scarcity and corresponding abiotic drought stress is one of the most important
factors limiting plant performance and crop yield. Similarly, crop productivity is also
severely compromised worldwide by infection with microbial pathogens. Two of the
most prominent pathways responsible for drought tolerance and disease resistance in
Arabidopsis are those controlled by the phytohormones abscisic acid (ABA) and methyl
jasmonate (MeJA). Through a functional genetic screen in the model system Arabidopsis
thaliana we have identified a node of integration for drought and plant immunity. The
functional integration and the control of drought and immune responses convey through
the OCP3 locus.
OCP3 is a highly conserved protein showing similarities to proteins containing the
conserved homeodomain (HD) and that are related to and function as transcriptional
regulators of plant gene expression in response to developmental and environmental cues.
The Arabidopsis loss-of-function ocp3 mutant exhibits both drought tolerance and
enhanced disease resistance to necrotrophic fungal pathogens.
Double mutant analysis revealed that the OCP3 gene plays a pivotal role in the
control of the adaptive responses to these two stresses. OCP3 is revealed as a negative
regulator of these two pathways leading to enhance stress tolerance by functioning as a
modulator of independent and specific aspects of the ABA- and MeJA-mediated signal