Role of auxin-responsive genes in biotic stress responses

Abstract

Although the phytohormone auxin has been implicated primarily in developmental processes, some recent studies suggest its involvement in stress/defense responses as well. Recently, we identified auxin-responsive genes and reported their comprehensive transcript profiling during various stages of development and abiotic stress responses in crop plant rice. The analysis revealed tissue-specific and overlapping expression profiles of auxin-responsive genes during various stages of reproductive development. In addition, a large number of auxin-responsive genes were also found to be differentially expressed under various abiotic stress conditions. Here, we further analyze the expression profiles of auxin-responsive genes during various biotic stress conditions. Several auxin-responsive genes showed response to biotic stress as well. Our analysis provides evidence for role of auxin in plant defense responses and suggests cross-talk between auxin, abiotic stress and biotic stress signaling pathways.

Figure 1

Differential expression of auxin-induced (A), auxin-repressed (B) and members of auxin-related gene families (C) in response to various biotic stress conditions. Venn diagrams represent number of genes commonly and uniquely differentially expressed by M. grisea and S. hermonthica infection. Hierarchical clustering of the genes showing significant differential expression in at least one condition is shown. The fold change values in treated sample as compared to its corresponding mock-treated control sample were used for clustering. The color scale for fold change values is shown at the bottom. Dpi, days post-inoculation. An enlarged version of heatmaps from this figure and fold change values are available as Supplemental Figure S1 and Table S1, respectively.