ConA-Loaded PEGylated Graphene Oxide for Targeted Nanopesticide Carriers against Magnaporthe Oryzae

Rice blast is a destructive rice disease that is rapidly spread by the drift of Magnaporthe oryzae spores. Conidial attachment to the rice leaf surface is the most crucial step in the rapid spread of rice blast. Therefore, blocking the chance of contact between spores and the rice leaf surface is extremely vital for controlling rice blast. In this study, based on the strong affinity between the lectin protein-ConA and M. oryzae spores, we successfully constructed ConA-loaded PEGylated graphene oxide (GO-PEG-ConA) as targeted nanopesticide carriers to load epoxiconazole (EPX) against M. oryzae. The ConA loading capacity of the GO-PEG-EPX-ConA nanocarrier was 14.7% by the sodium dodecyl sulfate–polyacrylamide gel electrophoresis assay. The GO-PEG-ConA nanocarrier could obviously inhibit the germination of M. oryzae spores by 41.7% and showed 2.4-fold higher inhibitory activity than the inhibition ratio (17.4%) of GO-PEG nanocarriers, which was mainly due to the higher affinity between the GO-PEG-ConA nanocarrier and M. oryzae spores. Moreover, the greenhouse experiment indicated that the GO-PEG-EPX-ConA nanopesticide could significantly reduce rice blast lesions in rice seedlings, fundamentally settling the transmission of rice blast. Therefore, GO-PEG-ConA could be a targeted nanopesticide carrier to realize precise release of pesticides, which would offer an important reference value for improving pesticide utilization efficiency.