The findings, outlined in a paper titled "VPEg Exhibits a Caspase-like Activity that Contributes to Defense Against Pathogens" were reported in the Sept. 23, online issue of Current Biology, and involve research on the key plant protein, vacuolar processing enzyme or VPEg, in Arabidopsis thaliana, or thale cress, that is required for this process.
Programmed cell death (PCD), which occurs naturally in all multi-cellular organisms, is the regulated elimination of cells that happens during the course of development, as well as in response to bacterial, fungal and viral infection. Caspases are a family of proteases, or enzymes that degrade proteins, which play an essential role in initiating and carrying out programmed cell death in animals.
Caspase-like activities have also been shown to be required for the initiation of programmed cell death in plants, but the genes controlling those activities have not been identified.
Natasha Raikhel, Director of the UCR Center for Plant Cell Biology, and her former postdoctoral researcher, Enrique Rojo, have now shown that this key plant protein contributes to defense against bacterial, fungal and viral pathogens in plants by activating programmed cell death pathways.
They have discovered that mutants lacking this protein have an increased susceptibility to these pathogens. These results have significant influence in the outcome of a diverse set of plant-pathogen interactions and suggest that this key plant protein is likely involved in a variety of processes that range from stress and defense responses to proper development during aging.