Shedding light on the role of photosynthesis in pathogen colonization and host defense

Betiana S. Garavaglia, Ludivine Thomas, Natalia Gottig, Tamara Zimaro, Cecilia G. Garofalo, Christoph A Gehring, Jorgelina Ottado

Research output: Contribution to journalArticlepeer-review


The role of photosynthesis in plant defense is a fundamental question awaiting further molecular and physiological elucidation. To this end we investigated host responses to infection with the bacterial pathogen Xanthomonas axonopodis pv. citri, the pathogen responsible for citrus canker. This pathogen encodes a plant-like natriuretic peptide (XacPNP) that is expressed specifically during the infection process and prevents deterioration of the physiological condition of the infected tissue. Proteomic assays of citrus leaves infected with a XacPNP deletion mutant (DeltaXacPNP) resulted in a major reduction in photosynthetic proteins such as Rubisco, Rubisco activase and ATP synthase as a compared with infection with wild type bacteria. In contrast, infiltration of citrus leaves with recombinant XacPNP caused an increase in these host proteins and a concomitant increase in photosynthetic efficiency as measured by chlorophyll fluorescence assays. Reversion of the reduction in photosynthetic efficiency in citrus leaves infected with DeltaXacPNP was achieved by the application of XacPNP or Citrus sinensis PNP lending support to a case of molecular mimicry. Finally, given that DeltaXacPNP infection is less successful than infection with the wild type, it appears that reducing photosynthesis is an effective plant defense mechanism against biotrophic pathogens.
Original languageEnglish (US)
Pages (from-to)382-384
Number of pages3
JournalCommunicative & Integrative Biology
Issue number4
StatePublished - Oct 31 2014

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KAUST Repository Item: Exported on 2020-10-01


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