A proteomic method combining two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and matrix-assisted laser desorption/ionization-time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF) was used to compare the protein expression profiles of phosphine-resistant (PH3-R) and -susceptible (PH3-S) strains of Sitophilus oryzae. Thirty-nine differentially expressed protein spots were identified between the PH3-R and PH3-S strains; 20 protein spots were upregulated, and 19 protein spots

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... were downregulated in the PH3-R strain compared with their expression in the PH3-S strain. In particular, cytochrome oxidase subunit I showed 15-fold higher expression in the PH3-R strain than in the PH3-S strain. Additionally, citrate synthase 2, delta-1-pyrolline-5-carboxylate dehydrogenase, and triose-phosphate isomerase were highly expressed in the PH3-R strain. In summary, our study has improved understanding of the molecular mechanisms of phosphine resistance in the rice weevil.