Expression of PEI-coated gold nanoparticles carrying exogenous gene in periwinkle mesophyll cells and its practice in huanglongbing research

Summary Huanglongbing ( HLB ) is a devastating disease of citrus, which is mostly caused by Candidatus Liberibacter asiaticus (C Las ). To realize the specific application of nano-transgenic technology in HLB, AuNPs-PEI (Gold Nanoparticles-Polyethylenimine) was used to carry foreign genes into the leaves of periwinkle ( Catharanthus roseus ) by infiltration. Here, we demonstrated that NPR1-GFP protein expression was observed from the 12th hour to the 10th day after infiltrating AuNPs-PEI-pNPR1 ( Arabidopsis thaliana nonexpressor of pathogenesis-related gene 1 )-GFP. Fluorescence of mCherry was observed 6 h after AuNPs-PEI-pNLS (nuclear localization signal sequence)-mCherry infiltration and fluorescence of FAM was observed in the nucleus 4 h after AuNPs-PEI-FAM-siRNA NPR1 infiltration. In addition, NPR1-GFP expression in C Las-infected periwinkle leaves was significantly higher than that in healthy periwinkle leaves after infiltration. Our work confirmed that the expression of exogenous NPR1-GFP could reduce the C Las titers by promoting the expression of PR ( pathogenesis related ) genes and ICS ( isochorismate synthase ) gene.