HopW1-1 is a family of bacterial modular P. syringae Avr effectors that induce accumulation of the signal molecule salicylic acid (SA) and the transcripts of HWI1 (HOPW1-1-INDUCED GENE1) in Arabidopsis. Thus HopW1-1 elicits a resistance response in Arabidopsis [1].

1: Arabidopsis proteins important for modulating defense responses to Pseudomonas syringae that secrete HopW1-1. Lee MW, Jelenska J, Greenberg JT; Plant J. 2008;54:452-465. PMID:18266921