April 19, 2011
MU Researchers Find Missing Link In Plant Defense Against Fungal Disease
Botrytis bunch rot, a disease caused by the fungal pathogen Botrytis cinerea, can devastate grape vineyards. Yet other plants can repel the invader and protect themselves by mounting a form of chemical warfare against the fungi through the production of antimicrobial substances, called phytoalexins.
Scientists at the University of Missouri report on a discovery in a key component in the signaling pathway that regulates the production of phytoalexins to kill the disease-causing fungus Botrytis cinerea.
In previous work, Zhang and his colleagues showed a signaling pathway, known as MAPK cascade, triggers the transcription activation of genes that make camalexin in Arabidopsis. This study shows that the target of this signaling cascade is the WRKY33 transcription factor.
Arabidopsis plants lacking the gene are unable to synthesize camalexin and are more susceptible to the Botrytis cinerea fungus.
The finding provides an important missing link in the chain of molecules that tells the plant to mount an appropriate defense against an invading microbe.
"Phytoalexins are one important way plants defend themselves naturally against pathogens. Knowing how plants regulate this defense response may allow us to naturally enhance pathogen tolerance in plants," Zhang said.
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