Marker-Exchange Mutagenesis and Complementation Strategies for the Gram-Negative Bacteria <i>Xanthomonas oryzae</i> pv. <i>oryzae</i>

This chapter describes methods for targeted knockouts using marker exchange mutagenesis and complementation of the Gram-negative bacteria Xanthomonas oryzae pv. oryzae. We have used these methods to demonstrate that type I secretion and modification systems are involved in avrXa21 activity of X. oryzae pv. oryzae.