Tomato is the highest-value fruit/vegetable crop worldwide. However, the quality and yield of tomatoes are severely affected by late blight. MicroRNA482s (miR482s) are involved in plant immune system. In this study, miR482c was transiently and stably overexpressed in tomatoes in transgenic plants to explore its mechanism in tomato resistance against late blight. Tomato in transgenic plants transiently overexpressed miR482c displayed larger lesion area than the control plants upon infection. Furthermore, compared with the WT tomato plants, the transgenic tomato plants stably overexpressing miR482c displayed decreased expression of target genes accompanied by lower POD, SOD, and PAL activity activities and higher MDA content, thereby leading to a decline in the ROS scavenging ability and aggravating the damage of lipid peroxidation product accumulation on the cell membrane, eventually enhancing plant susceptibility. This finding indicates that miR482c may act as a negative regulator in tomato resistance by regulating NBS-LRR expression levels and ROS levels.

Cellobiose phosphorylase (CBP) catalyzes the reversible phosphorolysis of cellobiose into α-glucose 1-phosphate and glucose. When it was used in transforming cellulose to amylose (PNAS, 110: 7182-7187, 2013) as well as in constructing a yeast with the ability to phosphorolytically use cellodextrin to produce ethanol, a CBP with a broadened substrate specificity would be more desirable. Based on the structure differences in the catalytic loops of CBP and cellodextrin phosphorylase from Clostridium thermocellum (named CtCBP and CtCDP, respectively), CtCBP was mutated. A single-site mutant S497G was identified to have a 5.7-fold higher catalytic efficiency with cellotriose as a substrate in phosphorolytic reaction direction compared to wild type, without any loss of catalytic efficiency on its natural substrate cellobiose. When S497G variant was used in the transformation of mixed cellodextrin (cellobiose + cellotriose) to amylose, a significant increase in amylose yield was achieved compared to that of wild type CtCBP. Structure change in the substrate binding pocket of S497G variant accounted for its capacity to accept longer cellodextrins than cellobiose. Taken together, S497G variant of CtCBP was confirmed to acquire a promising feature favorable to those application scenarios involving cellodextrin’s phosphorolysis.

Here, we found higher percentage of CD8+ T cells in piglets immunized with CVC1302-adjuvanted inactivated FMDV vaccine. We wonder whether promoted cellular immunity induced by CVC1302-adjuvanted inactivated FMDV vaccine due to the promoted antigen cross-presentation efficiency of OVA by DC mainly via the cytosolic pathways, demonstrated by enhanced levels of lysosomal escape of OVA in DC, loaded with OVA and CVC1302. Higher levels of ROS and significant enhanced elevated lysosomal pH in DC facilitated the lysosomal escape of OVA. Significant enhanced CTL activities were observed in mice immunized with OVA-CVC1302. Overall, CVC1302 increased the cross-presentation of exogenous antigens and the cross-priming of CD8+ T cells by alkalizing the lysosomal pH and facilitating the lysosomal escape of antigen. These studies shed new light on the development of immunopotentiators to improve the cellular immunity induced by vaccine.