Loading cinnamon oil into pH-sensitive chitosan grafted mesoporous silica nanoparticles via supercritical carbon dioxide.

Stimulus-responsive mesoporous silica nanoparticles (MSNs) have displayed great potentiality for controlled-release and targeted drug delivery. In the current work, a supercritical fluid method was utilized to successfully prepare cinnamon oil loaded into chitosan grafted MSNs (CO@CS-MSNs). The influencing factors of drug loads, such as pressure, temperature, impregnation time and depressure time, were investigated. The structure of CO@CS-MSNs was demonstrated with Fourier-transform infrared (FT-IR) spectroscopy, transmission electron microscope (TEM), scanning electron microscopy (SEM), thermogravimetry (TG) as well as X-ray diffraction (XRD). The drug release assays in vitro at various pH conditions displayed that CO@CS-MSNs had an excellent pH-responsive release behavior, which confirmed that CO was loaded successfully into the CO@CS-MSNs. The findings indicated that the supercritical fluid approach is a non-destructive and efficient approach for stimulus-responsive MSNs, which is expected to further expand its application range.

Susceptibility factor StEXA1 interacts with StnCBP to facilitate potato virus Y accumulation through the stress granule-dependent RNA regulatory pathway in potato.

Plant viruses recruit multiple host factors for translation, replication, and movement in the infection process. The loss-of-function mutation of the susceptibility genes will lead to the loss of susceptibility to viruses, which is referred to as 'recessive resistance'. Essential for potexvirus Accumulation 1 (EXA1) has been identified as a susceptibility gene required for potexvirus, lolavirus, and bacterial and oomycete pathogens. In this study, EXA1 knockdown in potato (StEXA1) was found to confer novel resistance to potato virus Y (PVY, potyvirus) in a strain-specific manner. It significantly compromised PVYO accumulation but not PVYN:O and PVYNTN. Further analysis revealed that StEXA1 is associated with the HC-Pro of PVY through a member of eIF4Es (StnCBP). HC-ProO and HC-ProN, two HC-Pro proteins from PVYO and PVYN, exhibited strong and weak interactions with StnCBP, respectively, due to their different spatial conformation. Moreover, the accumulation of PVYO was mainly dependent on the stress granules (SGs) induced by StEXA1 and StnCBP, whereas PVYN:O and PVYNTN could induce SGs by HC-ProN independently through an unknown mechanism. These results could explain why StEXA1 or StnCBP knockdown conferred resistance to PVYO but not to PVYN:O and PVYNTN. In summary, our results for the first time demonstrate that EXA1 can act as a susceptibility gene for PVY infection. Finally, a hypothetical model was proposed for understanding the mechanism by which StEXA1 interacts with StnCBP to facilitate PVY accumulation in potato through the SG-dependent RNA regulatory pathway.