Elicitation of cultured chickpea cells caused rapid insolubilization of two cell wall structural proteins, p190, a putative hydroxyproline-rich glycoprotein and p80, a putative proline-rich protein. This process appeared to result from an H2O2-mediated oxidative cross-linking mechanism and was initiated within 5 min and complete within 20 min. Further, elicitation of cells induced a rapid, transient generation of H2O2 (oxidative burst), with an onset after 5 min and a maximum H2O2-release after 20 min, as measured by a luminol-dependent chemiluminescence assay. Both chemiluminescence and protein insolubilization were suppressed by exogenous application of catalase or diphenylene iodonium, an inhibitor of plasma-membrane NADPH oxidase, respectively. In contrast, exogenous H2O2 mimicked the effect of the elicitor, suggesting that the putative oxidative crosslinking of the proteins depends directly on H2O2 from the oxidative burst. The peroxidase inhibitor salicylhydroxamic acid blocked both the elicitor- and the exogenous-H2O-stimulated insolubilization, indicating that a peroxidase activity downstream of H2O2-supply is required. The protein kinase inhibitor staurosporine blocked the elicitation of the oxidative burst and protein insolubilization. In contrast, the protein phosphatase 2A inhibitor cantharidin accelerated, potentiated and extended the elicited oxidative burst. Cantharidin even stimulated the responses in the absence of the elicitor. The competitive effect of both inhibitors confirms that a coordinated activation of (i) protein kinase(s) and (ii) counteracting protein phosphates(s) is a poised signal transduction step for the induction of an NADPH-oxidase-dependent oxidative burst, which drives the putative peroxidase-catalyzed cross-linking of the cell wall proteins.