Cross-Talk Between Phytohormone Signaling Pathways Under Both Optimal and Stressful Environmental Conditions

The perception of abiotic stress triggers the activation of signal transduction cascades that interact with the baseline pathways transduced by phytohormones. The convergence points among hormone signal transduction cascades are considered cross-talk, and together they form a signaling network. Through this mechanism, hormones interact by activating either a common second messenger or a phosphorylation cascade. This chapter reviews kinase cascades as cross-talk points in hormonal networks during abiotic stress conditions. These transduction cascades lead to the regulation of gene expression that directly affects the biosynthesis or action of other hormones. Examples of stress-related hormone transduction networks are provided for drought and wounding conditions. The expression of specific genes associated with drought and wounding stress will be compared with expression changes that occur during other abiotic stress conditions. This evaluation will be used to construct a model of abiotic stress signaling that incorporates the signaling components that are most common across all abiotic stress conditions and are, therefore, relevant to developing stress tolerance in crop plants.