Figure 5.

Functional analysis of the results of microarray profiles. Red and green letters represent induced and repressed genes respectively. Gray words represent genes constitutively expressed under our study conditions (name of genes or their identifiers are in parenthesis). We propose that induction of some genes is related to the presence of host components in the medium (leaf and apoplast). Similarly, repression of genes involved in iron acquisition, suggests that host extracts are a non-limiting source of this element. The figure also shows results of RT-PCR validation; control culture without extract (A, at the left) and test culture with bean leaf extract (B, to the right). Nine up-regulated genes were selected for RT-PCR analysis. The independent determination of transcript levels using RT-PCR analysis was congruent with the microarray data. Additionally we included genes involved in protection against oxidative stress such as catalase A (katA), and genes involved in TTSS (hrpJ, HopAB1, avrB2), which in the case of the latter are also included as controls in the microarrays and the fur gene.