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Poster

Session: Session 2 Presenting Authors at Posters (Odds)

P-079 - The rpfF gene from Xylella fastidiosa induces a priming effect in transgenic sweet orange plants (cultivar ‘Pineapple’) and increases resistance to HLB

Wednesday, July 16, 2025
13:30 - 15:15  
Location: Confex Hall 3
Crop resistance genetics and genomics

    Author(s)

  • VD

    Victoria Stern Da Silva

    Master student
    Citrus Research Center "Sylvio Moreira" - Agronomic Institute/IAC
    Cordeirópolis, Sao Paulo, Brazil

  • MS

    Mariana Souza e Silva

    Post-Doc
    Citrus Research Center "Sylvio Moreira" - Agronomic Institute/IAC
    Cordeirópolis, Sao Paulo, Brazil

  • PT

    Paulo Teixeira (he/him/his)

    Assistant Professor
    University of Sao Paulo/
    Piracicaba, Sao Paulo, Brazil

  • BP

    Bárbara Aliende Pires

    Doctoral student
    Luiz de Queiroz College of Agriculture, University of São Paulo – ESALQ/USP
    Piracicaba, Sao Paulo, Brazil

  • ME

    Mariana Bossi Esteves

    Post-Doc
    Citrus Research Center "Sylvio Moreira" - Agronomic Institute/IAC
    Araras, Sao Paulo, Brazil

  • SL

    Steven Lindow

    Scientific Researcher
    University of California/Berkeley
    Berkeley, California, United States

    • Presenting Author(s)

  • AD

    Alessandra Alves De Souza

    Scientific Researcher
    Citrus Research Center "Sylvio Moreira" - Agronomic Institute/IAC
    Cordeiropolis, Sao Paulo, Brazil

Brazil is the largest producer of sweet oranges and the leading exporter of orange juice, but several bacterial diseases threaten the citrus industry. To address this, we developed a transgenic sweet orange overexpressing rpfF, confering synthesis of diffusible signaling factor (DSF) a fatty acid mediating quorum sensing (QS) in Xylella fastidiosa (causal agent of citrus variegated chlorosis, CVC) and Xanthomonas citri (causal agent of citrus canker, CC). DSF-expressing plants disrupted bacterial communication, reducing CC and CVC in the greenhouse. In the field, these genetically modified plants (GMO) also exhibited a significant reduction in HLB symptoms. Since Candidatus Liberibacter asiaticus, the causal agent of HLB, lacks a QS system regulated by DSF, we hypothesized that DSF might act as an elicitor. Lipid extracts from GMO, but not wild-type (WT) plants, conferred a hypersensitive response (HR) when infiltrated into Nicotiana benthamiana. Transcriptomic and lipidomic analyses were performed to identify the genetic and lipid profiles associated with resistance in GMO plants. Differential gene expression revealed 35 upregulated genes unique to GMO plants, with several associated with plant defense against biotic stress. In addition, lipidome analysis identified 7 distinct lipid molecules more abundant in GMO, primarily acting as signaling molecules. Overall, our results suggest that RpfF generates a small unsaturated fatty acid, priming resistance against HLB.