Mechanism of Phytoalexin Induction

Abstract

In conclusion, it appears that pisatih-inducing compounds are not unique to plant, pathogenic fungi. We have recently observed that foreign cells, such as pollen grains and mouse tumor cells, effectively induce pisatin synthesis in pea tissue. It is likely that phytoalexin production is a type of incompatibility response initiated by any of a diverse group of compounds which are released by fungal pathogens and other foreign cell types when intimately associated with pea tissues. In general, the more unrelated cell types incite a more intense response than the closely related cell types. The mode by which the diverse cell types induce pisatin may be variable, but the response is consistently dependent on transcription of new genetic message.
The message needed for maximal pisatin production could be associated with a segment of chromatin which becomes readily accessible to RNA polymerase following a variety of changes in DNA conformation. Since there are numerous ways to alter DNA conformation, one might also expect that induction could be initiated by a chemically diverse group of compounds.