It’s been 20 years since the identification of BRI1, the first brassinosteroid (BR) receptor. Although many components of the BR signaling pathways have been identified, details continue to be revealed. Kang et al. examined the phenotype of a triple mutant, bri1 brl1 brl3, that lacks all three functional BR receptors. Root elongation and protophloem differentiation […]
Arabidopsis has three membrane-located, histidine-kinase cytokinin (CK) receptors (AHK2, 3, and 4). Loss-of-function mutants suggest that AHK2 and AHK3 function somewhat redundantly. To further explore the roles of these receptors, Bartrina and Jensen et al. isolated dominant gain-of-function mutants, repressor of cytokinin deficiency2 (rock2) and rock3. As expected, these GoF mutants show enhanced CK signaling […]
Glenn et al. introduce a new method for the labeling and purification of newly-synthesized proteins from intact tissues. The method, named BONCAT (Bioorthogonal Non-Canonical Amino Acid Tagging) involves the incorporation of the non-canonical methionine surrogate azidohomoalanine (Aha) into newly synthesized proteins. Aha has a reactive azide side chain that can be conjugated for instance to […]
Continuing the theme of peptide signaling, Stegmann et al. showed that a subset of the RALF (RAPID ALKALINIZATION FACTOR) family of plant peptides can negatively regulate plant immune responses. When plants are treated with flg22, a peptide epitope of bacterial flagellin, they produce reactive oxygen species (ROS) as part of their defense response. The flg22 […]
The Casparian strip is a permeability barrier that seals the spaces between root endodermis cells and so prevents bulk-flow uptake of solutes. Previously, a leucine-rich repeat receptor kinase called SCHENGEN3 or GASSHO1 (GSO1/SGN3) was identified as necessary for normal Casparian strip formation. Now, two papers in Science show that the interaction between diffusible peptides and […]
Powdery mildew disease is a broad term that encompasses more than 650 species of powdery mildew fungi that affect about 10,000 plant species, with serious economic consequences. In the 1930s/40s, broad-spectrum resistance to powdery mildew was found in barley with a loss-of-function of the Mildew resistance locus o (Mlo) gene. Subsequently, resistance conferred by induced […]
The interaction between angiosperms and their pollinators provides an excellent system to study co-evolution, and underpins the evolution of the biosynthesis of numerous interesting and useful specialized metabolites, from pigments to fragrances. Borghi et al. review the metabolic pathways that produce these signals and rewards for pollinators. Classes of compounds discussed in terms of synthesis […]
IN BRIEF: Nancy R. Hofmann [email protected] Plant development and responses to the environment hinge on the ability to target proteins to different areas of the plasma membrane within a cell. Indeed, the establishment of polar distributions of proteins such as PIN auxin transporters is among the key responsibilities of the endomembrane trafficking system (reviewed in […]
Magnaporthe oryzae is the fungus that causes rice blast disease, which is a serious threat to food security. Ortiz et al. explore the interaction between AVR-Pia, a fungal effector protein, and RGA5, a rice NLR (nucleotide-binding domain and leucine-rich repeat protein) immune receptor protein. RGA5 has a C-terminal domain, RATX1, that acts as an integrated […]