8/3/04 (VJC)
Recommendation of new papers in the past several months for Faculty 1000.

JASMONATE-INSENSITIVE1 encodes a MYC transcription factor essential to discriminate between different jasmonate-regulated defense responses in Arabidopsis.
Lorenzo O, Chico JM, Sánchez-Serrano JJ, Solano R
Plant Cell 2004 Jul 16(7):1938-1950

This study reports a very interesting and exciting finding that the Arabidopsis JASMONATE-INSENSITIVE1 (JIN1) encodes AtMYC2 that is activate by JA and differentially regulates the expression of two groups of JA-induced genes. One group of genes in wounding responses (e.g., VSP2) are activated by AtMYC2 but are repressed by ERF1 and ethylene signaling. The other group of genes (e.g., PDF1.2) are involved in defense responses and are repressed by AtMYC2 but activated by ERF1 and ethylene signaling. Since AtMYC2 is also activated by ABA and important for a branch of ABA signaling, the complex interactions in the JA, ethylene and ABA signaling network deserve further investigation.

MAPMAN: a user-driven tool to display genomics data sets onto diagrams of metabolic pathways and other biological processes.
Thimm O, Bläsing O, ..., Rhee SY, Stitt M
Plant J 2004 Mar 37(6):914-39

MAPMAN is a very useful new tool to facilitate biological interpretation of large data sets and form experimentally testable hypothesis by displaying gene expression and metabolite profiling information onto organized diagrams of key metabolic pathways and important biological processes and regulatory pathways. Its user-driven and modular structure allows users to edit existing >200 hierarchical categories, add new categories, and develop SCAVENGER modules for new data analysis. MAPMAN adds new power to the commonly used clustering and AraCyc tools for global gene expression data analysis and data mining specifically designed for plants.

A Haplotype-Specific Resistance Gene Regulated by BONZAI1 Mediates Temperature-Dependent Growth Control in Arabidopsis
Shuhua Yang and Jian Hua
The Plant Cell, Vol. 16, 1060íV1071, April 2004

The work reveals an important regulatory role of BONZAI1 (BON1) in connecting temperature-dependent growth control and the repression of a TIR-NBS-LRR resistance gene SNC1 signaling. The growth defect of bon1-1 is a result of constitutive defense signaling involving EDS1, an EDS1 homologue, PAD4, SID2/ICS and SA in a positive feedback loop but not NDR1 required for some CC-NBS-LRR signaling.

Bacterial disease resistance in Arabidopsis through flagellin perception
Cyril Zipfel, Silke Robatzek, Lionel Navarro, Edward J. Oakeley, Jonathan D. G. Jones, Georg Felix1 & Thomas Boller
NATURE 428, 764, 2004

This paper demonstrated conclusively the importance of pathogen-associated molecular patterns (PAMPs) in plant disease resistance. It is shown that treatment of flg22 (an active flagellin peptide elicitor) and crude bacterial extracts enhanced resistance to bacterial pathogens even in the absence of the flg22 receptor, indicating the existence of functional perception systems for multiple PAMPs. Global gene expression and mutant analyses suggested that the flg22-induced resistance was mostly independent of salicylic acid, jasmonic acid and ethylene signaling.

A protein kinase target of a PDK1 signalling pathway is involved in root hair growth in Arabidopsis
Anthony RG, Henriques R, ..., Koncz C, Bögre L
EMBO J 2004 Feb 11 23(3):572-81

This paper reports the first Arabidopsis protein kinase cascade in lipid signaling, consisting the 3íŽ-phophoinositide-dependent kinase (AtPDK1) and a specific AGC kinase AGC2-1 acting downstream of phosphatidic acid (PA) involved in stress and hormonal signaling. It is shown that AGC2-1 is abundant in dividing cells and fast-growing organs, and plant hormone auxin and cytokinin synergistically activate the AtPDK1-regulated AGC2-1 kinase, suggesting a role in cell cycle and growth. The agc2-1 loss-of-function mutant shows reduced root hair growth and development.

A MAPKK Kinase Gene Regulates Extra-Embryonic Cell Fate in Arabidopsis

Wolfgang Lukowitz, Adrienne Roeder, Dana Parmenter, and Chris Somerville

Cell, Vol. 116, 109íV119, January 9, 2004

An Arabidopsis MAP kinase kinase kinase (MAPKKK) gene YODA has been discovered to execute the first cell fate decision for basal lineage, which forms the extra-embryonic suspensor after the asymmetric division of the zygote. Expression of the constitutively active YODA could suppress proembryo formation and the loss-of-function mutants also exhibit abnormal embryogenesis and postembryonic development. Since YODA transcript is expressed ubiquitously and the same MAPKKK could often function in distinct MAPK pathways, it is possible that YODA might have other important functions throughout embryogenesis and plant development.