www.czu.cz ; www.raupp.info

RIVERSIDE, Calif. ? Scientists from the University of California, Riverside
have identified one of the key enzymes that trigger programmed cell death,
an important process plants undergo in fighting off bacterial, fungal or
viral infections. The development holds out hope of improving crop yields,
which are dependent on plants being able to fend off multiple types of
pathogens, October 2004.

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.

This is an important discovery because it demonstrates a previously unknown
mechanism through which plants control cell death. ?Programmed cell death is
a universal process that all multicellular organisms must control throughout
growth and development,? explained Raikhel. ?Since PCD plays such a central
role in a wide variety of physiological processes, the VPE pathway for
controlling PCD likely has a huge impact on this process in plants.?

The research, funded by the National Science Foundation, was carried out
from 2002-2004 in the Department of Botany and Plant Sciences and the Center
for Plant Cell Biology (CEPCEB) at UC Riverside and the Universidad Autónoma
de Madrid.

Besides Raikhel and Rojo, UCR co-authors of the Current Biology paper
include Clay Carter, Jan Zouhar, Songqin Pan, and Hailing Jin. Co-authors
from other institutions include Raquel Martin, Manuel Paneque and Jose Juan
Sanchez-Serrano of the Departamento de Genética Molecular de Plantas del
Centro Nacional de Biotecnología, Consejo Superior de Investigaciones
Cientificas, Madrid, Spain; Frederick M Ausubel and Julia Plotnikova of the
Department of Genetics at Harvard Medical School and the Department of
Molecular Biology at Massachusetts General Hospital, Boston; and Barbara
Baker of the Plant Gene Expression Center at UC Berkeley & the U.S.
Department of Agriculture.

Additional Contacts: Natasha Raikhel natasha.raikhel@ucr.edu

The University of California, Riverside is a major research institution and
a national center for the humanities. Key areas of research include
nanotechnology, genomics, environmental studies, digital arts and
sustainable growth and development. With a current undergraduate and
graduate enrollment of nearly 17,000, the campus is projected to grow to
21,000 students by 2010. Located in the heart of inland Southern California,
the nearly 1,200-acre, park-like campus is at the center of the region's
economic development. Visit www.ucr.edu or call 951-UCR-NEWS for more
information. Media sources are available at
[www.mediasources.ucr.edu].

------------------------------------------
Posted to Phorum via PhorumMail