The results showed that bacteria repress genes involved in iron acquisition, induce iron dependant enzymes and iron storage click here proteins (bacterioferritin) that provide the cofactor Fe2+ for catalase, which is involved in protection against oxidative stress. These responses allow P. syringae pv. phaseolicola NPS3121 to adapt to media supplemented with plant extracts. In addition, the results demonstrate that for many genes, a significant increase in

expression is probably due to plant signal molecule(s) found in bean extracts. The role of some of these gene products such a pectin lyase, polygalacturonase and TTSS proteins during the first stages of the plant-bacterial interaction and the role of phaseolotoxin in virulence has previously been reported. Furthermore, this study suggests that to obtain information of genes required for the late stages in the infective process, other approaches such as gene expression analysis in infected tissue may be required. This type of analysis could provide information about processes occurring during metabolic

mTOR inhibitor adaptation to host tissue, disease development ranging from first stages to the development of symptoms and bacterial physiology influenced by responsive factors such as antimicrobials and other defensive metabolites inside the plant cell. Methods Assembly of a DNA microarray of P. syringae pv. phaseolicola NPS3121 (see Figure 2) Genomic DNA from P. syringae pv. phaseolicola NPS3121 was isolated as described previously [63], partially digested with Sau3AI and run on a continuous sucrose gradient to recover fragments with an average

size of 3 kbp. The genomic fragments were ligated into the plasmid vector pUC19 (Invitrogen, California, USA) previously digested with BamHI, and the ligation mixture was used to Exoribonuclease transform Escherichia coli TOP10 cells (Invitrogen, California, USA). Transformants were transferred to 96-well microplates, grown overnight and plasmids were recovered. A total of 9792 recombinant clones were obtained with an average insert size of 2.6 kbp giving an estimated 4× coverage of the P. syringae pv. phaseolicola NPS3121 genome whose size is reported to be 5640 Mpb [64]. Around 30% of the genomic clones were randomly selected and partially sequenced in a single direction using the forward M13-primer (5′-CCCAGTCACGACGTTGTAAAACGAC) by the Sanger method. 2880 sequences with an average size of 531 pb were obtained. Using the MUMmer system each sequence was aligned and annotated against the complete genome sequence of P. syringae pv. phaseolicola 1448A [23]. This strategy allowed us to select those clones that provided approximately 1× coverage of the genome, eliminating redundancy and providing information regarding the identity of the 5′ end of each clone.