A newly discovered manipulation mechanism used by parasitic bacteria to
slow down plant aging, may offer new ways to protect disease-threatened
food crops.

Parasites manipulate the organisms they live off to suit their needs,
sometimes in drastic ways. When under the spell of a parasite, some
plants undergo such extensive changes that they are described as
�??zombies�?�. They stop reproducing and serve only as a habitat and host
for the parasitic pathogens.

Until now, there�??s been little understanding of how this happens on a
molecular and mechanistic level.

Research from the Hogenhout group at the John Innes Centre and
collaborators published in/Cell/, has identified a manipulation molecule
produced by Phytoplasma bacteria to hijack plant development. When
inside a plant, this protein causes key growth regulators to be broken
down, triggering abnormal growth.

Phytoplasma bacteria belong to a group of microbes that are notorious
for their ability to reprogramme the development of their host plants.
This group of bacteria are often responsible for the �??witches�?? brooms�??
seen in trees, where an excessive number of branches grow close together.

These bushy outgrowths are the result of the plant being stuck in a
vegetative �??zombie�?� state, unable to reproduce and therefore progress to
a �??forever young�?? status.

Phytoplasma bacteria can also cause devastating crop disease, such as
Aster Yellows which causes significant yield losses in both grain and
leaf crops like lettuce, carrots, and cereals.

Professor Saskia Hogenhout, corresponding author of the study said:
�??Phytoplasmas are a spectacular example of how the reach of genes can
extend beyond the organisms to impact surrounding environments.

�??Our findings cast new light on a molecular mechanism behind this
extended phenotype in a way that could help solve a major problem for
food production. We highlight a promising strategy for engineering
plants to achieve a level of durable resistance of crops to phytoplasmas.�?�

The new findings show how the bacterial protein known as SAP05
manipulates plants by taking advantage of some of the host�??s own
molecular machinery.

This finding offers the possibility of tweaking just these two amino
acids in crops, for example using gene-editing technologies, to provide
durable resilience to phytoplasmas and the effects of SAP05.

This research is part of a collaboration between the John Innes Centre
and The Sainsbury Laboratory in Norwich, Wageningen University and
Research Centre in The Netherlands and Academia Sinica in Taiwan.  Two
former post-docs from the Hogenhout group are now independent
researchers at the University of Ottawa, Canada and the Institute of
Genetics, Environment and Plant Protection, France. Abbas Maqbool from
The Sainsbury Laboratory has recently taken a leading position in industry.

The microbial molecule that turns plants into zombies | John Innes
Centre (jic.ac.uk)
[www.jic.ac.uk]