AvrPtoB_bdg is a binding region on a family of bacterial plant pathogenic proteins. Type III effector proteins are injected into plants by bacteria when they are under attack, eg Pseudomonas syringae when attacking tomato. AvrPtoB is one such effector that suppresses the plants' PAMP-triggered innate immunity. PAMPs are pathogen/microbe-associated molecular patterns that are detected as non-self by a host. AvrPtoB suppresses this response by binding to BAK1, a kinase that acts with several pattern recognition receptors to activate defence signalling. AvrPtoB_bdg is the region of AvrPtoB that binds to BAK1 thereby preventing its kinase activity after the perception of flagellin [1].

1: Structural analysis of Pseudomonas syringae AvrPtoB bound to host BAK1 reveals two similar kinase-interacting domains in a type III Effector. Cheng W, Munkvold KR, Gao H, Mathieu J, Schwizer S, Wang S, Yan YB, Wang J, Martin GB, Chai J; Cell Host Microbe. 2011;10:616-626. PMID:22169508