Activation of the Tobacco SIP Kinase by Both a Cell Wall-Derived Carbohydrate Elicitor and Purified Proteinaceous Elicitins from Phytophthora spp
Year: 1998
Type: article
Abstract: Two purified proteinaceous fungal elicitors, parasiticein (an alpha elicitin) and cryptogein (a beta elicitin), as well as a fungal cell wall-derived carbohydrate elicitor all rapidly activated a 48-kD kinase in tobacco suspension cells. The maximum activation of this kinase paralleled or preceded medium alkalization and activation of the defense gene phenylalanine ammonia-lyase (PAL). In addition, the two elicitins, which also induced hypersensitive cell death, activated a 44- and a 40-kD kinase with delayed kinetics. By contrast, the cell wall-derived elicitor only weakly activated the 44-kD kinase and failed to activate the 40-kD kinase. The size and substrate preference of the 48-kD kinase are reminiscent of the recently purified and cloned salicylic acid-induced protein (SIP) kinase, which is a member of the mitogen-activated protein kinase family. Antibodies raised against a peptide corresponding to the unique N terminus of SIP kinase immunoreacted with the 48-kD kinase activated by all three elicitors from Phytophthora spp. In addition, the cell wall elicitor and the salicylic acid-activated 48-kD kinase copurified through several chromatography steps and comigrated on two-dimensional gels. Based on these results, all three fungal elicitors appear to activate the SIP kinase. In addition, inhibition of SIP kinase activation by kinase inhibitors correlated with the suppression of cell wall elicitor-induced medium alkalization and PAL gene activation, suggesting a regulatory function for the SIP kinase in these defense responses.
Source: The Plant Cell
DOI: 10.2307/3870600
Authors: Shuqun Zhang, He Du, Daniel F. Klessig
Institution: Rutgers, The State University of New Jersey
Language: English
Subfield: Plant Science
Domain: Life Sciences
Open Access status: bronze
Funder: National Science Foundation
OpenAlex ID: W2129860418