Figure 2.

Overview of the microarray strategy. A library of chromosomal DNA fragments of P. syringae pv. phaseolicola NPS3121 (Psp NPS3121) was constructed in the pUC19 vector and introduced into the E. coli Top10 strain. 30% (2880 clones) of the genomic library was sequenced, aligned and annotated against the complete genome of P. syringae pv. phaseolicola 1448A. This strategy allowed selection of 1911 clones that provided approximately 1× coverage of the genome. The fragments of 1911 clones were amplified by PCR reaction, and the products were printed on a microarray slide. This microarray was used to identify genes that are differentially expressed when bean leaf or pod extracts and apoplastic fluid were added to the growth medium.