Cover Illustration: Bruchins are a new class of insect-derived natural products that stimulate cell division and neoplasm formation when applied to pods of peas and certain other legumes. The isolation and characterization of the bruchins followed the observation that oviposition by the pea weevil Bruchus pisorum L., on pods of peas carrying the wild-type Neoplastic pod (Np) gene, resulted in browning followed by cell division and callus formation at the site of oviposition (as shown in the scanning electron micrograph image). Bruchin B application also results in the up-regulation of several genes, among them a putative isoflavone synthase gene, the cytochrome P450, CYP93C18. The up-regulation of CYP93C18 was followed by an increase in the level of the isoflavone phytoalexin, pisatin. This, the first report of the induction of phytoalexin biosynthesis by an insect elicitor, suggests that Bruchin B not only stimulates neoplasm formation but also activates other plant defence responses. To generate this image, a bruchin was spotted onto a pod of Np/Np peas spelling out the name 'bruchin' in callus tissue. (SEM photograph of the weevil egg on callus thanks to Dr William Proebsting and Mr Al Soeldner, Oregon State University.) (See Cooper et al., 1229-1237.)
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