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Oral: The Impact of Vector-Borne Bacteria Pathogen on Associated Hosts


How bacterial pathogens hijack cellular processes to turn plants into ‘Zombies’
S. HOGENHOUT (1), P. Pecher (1) (1) John Innes Centre, United Kingdom

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Phytoplasmas are bacterial parasites of plants that interfere with fundamental developmental processes turning their hosts into ‘Zombies’. The ‘Zombie’ plants look dramatically different from their uninfected peers, displaying for example witches' brooms and leafy flowers. Moreover, these plants become attractive to insect vectors, which distribute the parasites to other plants, which then also become ‘Zombies’. We have previously shown that virulence proteins SAP11 and SAP54 of aster yellows witches broom phytoplasma (AYWB) induce witches' brooms and leafy flowers, respectively. SAP11 and SAP54 act by destabilising specific TCP and MADS-box transcription factors. A SAP11 homolog was identified in maize bushy stunt phytoplasma (MBSP), a maize specialist. We found that SAP11_AYWB destabilises all plant class II TCP transcription factors and SAP11_MBSP only a few TCPs. SAP11_MBSP transgenic Arabidopsis and maize plants show witch’s broom phenotypes resembling brc1xbrc2 Arabidopsis and tb1 maize mutants. Thus, SAP11 effectors have evolved to target specific TCPs in their host plants.