About the Cover
Plant glutathione S-transferases (GSTs) comprise a diverse family of enzymes that participate in the trafficking and/or catabolism of a variety of organic molecules. For example, the Bronze2 (Bz2) gene, which encodes a type III GST, is required for the efficient vacuolar sequestration of anthocyanins in maize. On pages 1135-1149, Alfenito et al. explore the functional significance of GST sequence diversity. They have cloned Anthocyanin9 (An9), a petunia gene related to Bz2, by using a transposon-tagged line that produces flowers with wild-type (red) and mutant (pale) sectors, like the one depicted on the cover. Particle bombardment tests on an9 and bz2 mutants demonstrate that the corresponding genes are functionally interchangeable, even though An9 encodes a type I GST and therefore evolved from a distinct progenitor GST. These data suggest that the functions of AN9 and BZ2 converged as they acquired the ability to recognize anthocyanin ligands and as their production fell under the control of transcriptional activators of the anthocyanin biosynthetic pathway.
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Copyright © 2007 by the American Society of Plant Biologists
