Conferencia Dra. Pérez-Hedo

Activation of the citrus immune system as a sustainable strategy for HLB and its psyllid vectors control

PEREZ-HEDO, Meritxell¹

¹Instituto de Biología Molecular y Celular de Plantas (IBMCP), Consejo Superior de Investigaciones Científicas, Universitat Politècnica de València, Valencia, Spain
E-mail address: mepehe@ibmcp.upv.es

The Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Psyllidae) and the African citrus psyllid Trioza erytreae Del Guercio (Hemiptera: Triozidae) are the primary insect vectors of Candidatus Liberibacter asiaticus, the bacterial pathogen associated with Huanglongbing (HLB), the most destructive citrus disease worldwide. HLB induces symptoms including foliar mottling, premature fruit drop, root necrosis, and eventual tree collapse. Given the vector’s efficiency and lack of curative treatments, controlling HLB requires innovative integrated strategies. Our research demonstrates that activating citrus immune responses through exposure to the volatile compound (Z)-3-hexenyl propanoate [(Z)-3-HP] provides sustainable protection by triggering salicylic acid (SA) and jasmonic acid (JA)-mediated defense pathways. This immune priming significantly reduces D. citri oviposition, enhances attraction of its natural parasitoids (Tamarixia radiata and T. dryi), and limits pathogen acquisition and multiplication. Transcriptomic analyses in Citrange Carrizo rootstock revealed concurrent upregulation of immunity-related genes and antioxidant pathways (catalases, peroxidases, superoxide dismutase), along with suppression of CsPUB21, an HLB susceptibility gene. These findings indicate a dual defense mechanism combining immune activation with repression of negative regulators. We are currently developing an integrated biotechnological approach combining functional transcriptomics to identify key defense pathways, targeted silencing of susceptibility genes, rational selection of immune-inducing compounds and suppressor molecules, and controlled-release technologies using nanoformulations and encapsulation systems for precise, sustained field application. This work aims to establish next-generation plant protection strategies that induce specific, sustainable immune responses against HLB and its psyllid vectors.

Keywords: Volatile compounds, Plant defenses, Transcriptomics.