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Chemoprevention is a potential strategy to reduce lung cancer incidence and death. Recently, we reported that garlic oil significantly inhibits 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis. Diallyl disulfide (DADS) is a bioactive ingredient in garlic. Our goal was to examine the chemopreventive effectiveness and mechanism of DADS on NNK-triggered lung cancer in vivoand in vitroin the current investigation. The results indicated that DADS significantly reduced the number of lung nodules in the NNK-induced A/J mice. Consistent with the in vivoresults, DADS markedly inhibited NNK-induced decrease of MRC-5 cells’ viability. Mechanistically, DADS could promote Nrf2 dissociated from the Keap1–Nrf2 complex and accelerate Nrf2 nuclear translocation, which in turn upregulates its downstream target genes. Besides, DADS further inhibited the NF-κB signaling cascade, thus reducing the accumulation of inflammatory factors. Collectively, these discoveries supported the potential of DADS as a novel candidate for the chemoprevention of tobacco-carcinogen-induced lung cancer.

The cultivated tomato Solanum lycopersicumsuffered a severe attack by the whitefly Bemisia tabaci(Gennadius), causing damage to leaves by feeding as well as transmitting the tomato yellow leaf curl virus (TYLCV), while the wild tomato S. habrochaitesis considerably less appealing to this insect species. It is reported that B. tabacishows innate avoidance to R-curcumene, which is produced naturally by S. habrochaites. However, the mechanisms involved in the avoidance behavior of B. tabaciin response to this chiral compound are still unclear yet. In this study, the functional and binding characterization of odorant-binding protein 1 of B. tabaci(BtOBP1) were examined in vivoand in vitroagainst R-curcumene. The obtained results showed that BtOBP1 exhibits specific binding activity to R-curcumene, which acts as repellents to B. tabaci. By using a fluorescence-based binding assay, the difference of binding-affinity for R-curcumene between wild type BtOBP1 and the mutant BtOBP1 to R-curcumene was performed, which resulted in a single amino acid mutation (ASN108 > SER); moreover, BtOBP1-N108 displays significantly decreased binding affinities to R-curcumene. Most interestingly, a knock-down experiment with the BtOBP1 showed that the whitefly responses to R-curcumene are impaired. This study illustrated that BtOBP1 is a crucial protein involved in the perception and discrimination of R-curcumene. Our findings may provide an excellent chance of finding a suitable antagonist of eco-friendly features that can block the perception of chemosensory signals in insects, preventing behaviors like food-finding.

ABSTRACTProtein tyrosine phosphatases play essential roles in plant growth and development and in plant responses to biotic or abiotic stresses. We recently demonstrated that an atypical dual-specificity protein tyrosine phosphatase in plants, AtPFA-DSP3 (DSP3), negatively regulates plant salt tolerance. Here, we report that a homolog of DSP3, AtPFA-DSP5 (DSP5), affects the response of plants to high-salt conditions. A loss-of-function mutant of DSP5 showed reduced sensitivity to salt treatment at the seed germination and vegetative stages of development while a gain-of-function mutant of DSP5 showed increased sensitivity to salt stress. The salt responses of dsp3dsp5double-mutant plants were similar to those of dsp3and dsp5single-mutant plants. Gel overlay and firefly luciferase complementation assays showed that DSP5 interacts with MPK3 and MPK6 in vitroand in vivo. These results indicate that DSP5 is a novel negative regulator of salt responses in Arabidopsisthat interacts directly with MPK3 and MPK6.