Plant Immunity

Protein Degradation Maintains Plant Defenses

Science's STKE  19 Mar 2002:
Vol. 2002, Issue 124, pp. tw112
DOI: 10.1126/stke.2002.124.tw112

The innate immune response by which plants defend against certain pathogens includes interactions between a signal from the pathogen and a specific resistance (R) gene in the plant. Although there are a variety of R genes, and a veritable multitude of pathogens, the plant tends to respond with a limited repertoire of physiological responses. Azevedo et al. and Austin et al. analyze the signaling cascade initiated by activation of disease resistance (see the Perspective by Nishimura and Somerville). Several R proteins trigger responses through the RAR1 protein, which in turn interacts with the SGT1 proteins. These results implicate SGT1 in ubiquitin-targeted protein degradation. The two SGT1 variants in Arabidopsis seem to have divergent functions. Thus, at least part of the signaling cascade triggered by response to a pathogen may involve protein degradation.

C. Azevedo, A. Sadanandom, K. Kitagawa, A. Freialdenhoven, K. Shirasu, P. Schulze-Lefert, The RAR1 interactor SGT1, an essential component of R gene-triggered disease resistance. Science 295, 2073-2076 (2002). [Abstract] [Full Text]

M. J. Austin, P. Muskett, K. Kahn, B. J. Feys, J. D. G. Jones, J. E. Parker, Regulatory role of SGT1 in early R gene-mediated plant defenses. Science 295, 2077-2080 (2002). [Abstract] [Full Text]

M. Nishimura, S. Somerville, Resisting attack. Science 295, 2032-2033 (2002). [Abstract] [Full Text]