Plant Physiology

Sensing Pathogens

Science's STKE  21 Mar 2000:
Vol. 2000, Issue 24, pp. tw3
DOI: 10.1126/stke.2000.24.tw3

The mitogen-activated protein kinase (MAPK) cascades are conserved pathways in fungi, invertebrates, vertebrates, and plants. Although many MAPK-like plant kinases have been identified, associating the kinases with particular stimuli has been more challenging. Nühse et al. found that one of the Arabidopsis MAPKs, AtMPK6, is involved in the plant-pathogen pathway that is stimulated in response to general elicitors, such as bacterial flagellin peptide, citrus pectic fragments, hexameric chitin fragments, and xylanase. The activation of AtMPK6 was rapid and transient and for 3 of the 4 elicitors tested preceded the increase in pH associated with the cell's response to the elicitors. The activation of AtMPK6 was assayed in suspension cultures and in leaf tissue. The authors performed in vivo labeling and phosphoamino acid analysis to demonstrate that activation of AtMPK6 was accompanied by dual phosphorylation on tyrosine and threonine residues. These experiments provide the basis for further analysis of the plant MAPK pathways through biochemical and genetic methods.

Nühse, T.S., Pack, S.C., Hirt, H., and Boller, T. (2000) Microbial elicitors induce activation and dual phosphorylation of the Arabidopsis thaliana MAPK 6. J. Biol. Chem.275: 7521-7526. [Abstract] [Full Text]