1/12/05 (VJC)
Recommendation of new papers for Faculty 1000.

The N Terminus of Bacterial Elongation Factor Tu Elicits Innate Immunity in Arabidopsis Plants
The Plant Cell, Vol. 16, 34963507, December 2004

Gernot Kunze, Cyril Zipfel, Silke Robatzek, Karsten Niehaus, Thomas Boller, and Georg Felixa

The work provides comprehensive and convincing evidence for the identification of EF-Tu, a protein translation elongation factor, as a novel PAMP (pathogen-associated molecular pattern) capable of triggering innate immune responses and induced resistance in Arabidopsis plants. N-terminal acetylation of the synthetic peptides corresponding to the N terminus of EF-Tu exhibits potent activity to induce conserved defense responses.
The fact that EF-Tu represents particularly conserved structure of a large class of microbes and was also observed to act as a stimulator of a proinflammatory response in the presence of soluble CD14 in mammals suggests the possibility that EF-Tu, similar to flagellin, might act as a PAMP for the innate immune system of both animals and plants.

Phosphorylation of 1-Aminocyclopropane-1-Carboxylic Acid Synthase by MPK6, a Stress-Responsive Mitogen-Activated Protein Kinase, Induces Ethylene Biosynthesis in Arabidopsis.
The Plant Cell, Vol. 16, 33863399, December 2004

Yidong Liu and Shuqun Zhang

The finding reveals a novel mechanism responsible for the biosynthesis control of the plant stress hormone ethylene by stress-activated MAPK cascades. In a set of elegant experiments, the authors identified selected isoforms of 1-aminocyclopropane-1-carboxylic acid synthase (ACS2/6), the rate-limiting enzyme of ethylene biosynthesis, as substrates of Arabidopsis MPK6. Activated MPK6 phosphorylates the unique C-terminal tail of ACS2/6 to enhance protein stability and ethylene evolution.