Construction and characterization of a Xanthomonas oryzae pv. oryzae bacterial artificial chromosome library.

Xanthomonas oryzae pv. oryzae is an important plant pathogen which causes bacterial blight of rice. To facilitate genome studies of this bacterium, we have constructed a bacterial artificial chromosome (BAC) library of strain MAFF 311018. It consisted of 750 clones representing 16 genome equivalents, and had an insert size ranging from 20 to 220 kb with an average size of 107 kb. This library is the first to be constructed from a X. oryzae pv. oryzae strain. The usefulness of this library was demonstrated through polymerase chain reaction screening of 11 genes and the 16S--23S rDNA spacer region in a 192-clone subset, representing five genome equivalents. The results obtained showed an average of 5.9 BAC clones per screening. This result is in good agreement with the estimated size of the test library, indicating that the constructed BAC library can be used to facilitate genome analysis of X. oryzae pv. oryzae.