Volume 5 Issue 5, May 2009

Chemical biology is beginning to enhance our understanding of diverse cellular processes in plants, including endomembrane trafficking, hormone transport and cell wall biosynthesis. To reach its potential requires the development of a community-wide infrastructure of technology and expertise. We present some of the opportunities and challenges in this emerging branch of plant biology and offer some suggestions for enhancing the approach to the benefit of the community at large.

Jasmonates are important in defending plants against pathogens and in reproductive development. New evidence resolves the stereochemistry of the bioactive jasmonate hormone and suggests a chemical mechanism for modulating levels of the bioactive molecule in plants.

In the realm of modern drug discovery technologies, fragment-based approaches and virtual ligand screening are emerging alternative approaches to high-throughput screening (HTS). For as simple as it sounds, a hybrid approach in which fragments are discovered first in silico may be an unbeatable route to hit identification for some drug targets.

Labeling endogenous proteins in their natural environment with synthetic probes represents a major challenge in chemical biology. In a recent study, an elegant traceless labeling technique has been reported that allows attachment of biophysical probes to the targeted proteins in vivo.

A high-throughput one-hybrid screen identifies a regulator of the Arabidopsis thaliana circadian gene CIRCADIAN CLOCK ASSOCIATED1 (CCA1). CCA1 HIKING EXPEDITION (CHE) represses CCA1 and physically interacts with TIMING OF CAB1 (TOC1) to link TOC1 with CCA1 in the clock.

SGS3 is essential for antiviral silencing and the biogenesis of several classes of siRNAs in plants, but until now no biochemical function has been ascribed to it. Both SGS3 and a viral suppressor of RNA silencing have now been shown to selectively bind 5′ overhang–containing dsRNA, implicating this RNA as a new intermediate in the RNA silencing pathway.

Enhanced interactions between plant biology and chemical biology offer great potential for shared concepts, tools and insights that will advance each discipline. This special issue highlights emerging frontiers in plant chemical biology, with an emphasis on the networks of plant hormones that regulate plant growth and mediate plant interactions with their external environments.