Ultrasensitive and rapid diagnosis of Ustilaginoidea oryzae using electrochemical genosensor based on Au-Pd/violet phosphorene/boron nitride nanohybrid

Ustilaginoidea oryzae, the ascomycete fungus responsible for Rice False Smut (RFS), devastates global rice yields via rice panicles infection, threatening food security. To address the critical need for early pathogen detection, we developed an ultrasensitive electrochemical genosensor utilizing a gold‑palladium bimetallic nanoparticle (Au-PdNPs) decorated violet phosphorene/boron nitride (VP/BN) nanohybrid. The VP/BN support, synthesized via sonication-assisted liquid-phase exfoliation, enabled the uniform anchoring of Au-PdNPs through chemical reduction, creating an enhanced conductive interface. Thiolated DNA probes immobilized on Au-PdNPs via Au S bonds enabled specific recognition of U. oryzae DNA through hybridization. This design achieved exceptional sensitivity with a broad linear range (0.1 μM to 10 pM) and ultralow detection limit (3.67 pM), surpassing some traditional detection methods reported at present in speed and cost-efficiency. The genosensor exhibited high specificity against non-target sequences and delivered 96.6–98 % recovery in spiked rice samples, validating its effectiveness in practical applications. By integrating nanomaterials with electrochemical amplification, this work paves the way for field-deployable portable U. oryzae diagnostics in the future, offering a transformative strategy to mitigate economic and agricultural impacts.