Comparative profiling of volatile organic compounds associated to temperature sensitive resistance to wheat streak mosaic virus (WSMV) in resistant and susceptible wheat cultivars at normal and elevated temperatures.

To investigate changes in wheat resistance to wheat streak mosaic virus (WSMV) at normal and elevated temperatures and their effects on the emission of volatile organic compounds (VOCs), the profile of these compounds in WSMV-resistant (R) and susceptible (S) wheat cultivars were analyzed. VOCs were discovered in leaves of R and S cultivars inoculated to WSMV at 20 °C and 32 °C at 24, 48 and 72 h post inoculation (hpi) by GC. MS-HS-SPME. Many VOCs and related metabolic pathways of WSMV inoculated and control plants responded differently at low/high temperatures in R/S cultivars. Compounds such as 6-methyl-5-hepten-2-one and heptanal, represented the maximum abundance in R plants compared to S plants at earlier times especially, 48 hpi/20 °C. Also, at 32 °C, VOCs including heptanal and 2-pentenal had the highest increase in abundance at a later time. In addition, in R plants, several pathways were up-regulated commonly at 20 °C and 32 °C. Although, at 20 °C, they were activated at an earlier time. At 32 °C, most of these pathways were up-regulated at 72 hpi. The most important pathways correlated to combined stresses included lipoxygenase, cuticular wax biosynthesis, fatty acid and lipid biosynthesis. The pathway of phenyl ethanol biosynthesis was up-regulated only at 32 °C, which probably is specifically related to resistance to heat stress. Up-regulation of the lipoxygenase pathway appears to increase vector attractiveness and tolerance to biotic and abiotic stresses. Based on these results, is suggested that there is a particular synchronized regulation of defense-related multi-dimensional VOCs emitting network that is necessary for the occurrence of wheat defense responses against WSMV and/or heat. This research highlights the challenge of global warming and the breakdown of plant resistance to viruses which requires metabolic engineering of VOCs for sustainable agriculture.

Comparative metabolomics of temperature sensitive resistance to wheat streak mosaic virus (WSMV) in resistant and susceptible wheat cultivars.

In order to evaluate wheat resistance to wheat streak mosaic virus (WSMV) at low temperature and resistance breakdown at high temperature, metabolic profile of WSMV-resistant (R) and susceptible (S) wheat cultivars were analyzed. Metabolites were detected by UPLC-QTOF/MS in leaves of R and S plants challenged with WSMV at 20 °C and 32 °C, 24, 48 and 72 h post inoculation (hpi). WSMV and mock inoculated plants were used for discriminating the most significant metabolites and metabolic pathways affected at those temperatures. At 24 hpi/20 °C and 48 hpi/20 °C, the most important metabolites in R plants were coumarins, a limited number of lipids, and unknown compounds, while at 72 hpi/20 °C, in addition to coumarins, alkaloids and several amino acids were increased. Compared to 24 and 48 hpi, at 72hpi, in R plants most metabolic pathways were up-regulated at 20 °C. These resistance-related specific pathways included amino acid metabolism, lipid metabolism and alkaloids pathways. Also, several pathways were up-regulated at 32 °C.These combined heat stress and pathogen related pathways, included lipid metabolism and amino acid metabolism. Some carbohydrate metabolism pathways were considered as heat stress related pathways and could be associated with resistance breakdown. On the other hand, the increased expression of lipid compounds, especially 24 hpi at 32 °C in R plant, can be attributed to plant adaptation to combined stressors such as pathogen and high temperature. Increased susceptibility of R plants at 32 °C coincided with a down-regulated expression of components of signal transduction pathways or in a decreased level of metabolites related to this pathway, especially at a later time after infection, leading to decreased metabolite signaling. Decrease of signaling compounds under combined stress is a possible outcome of deactivating WSMV specific signaling networks leading to compatible response in R plants. The significance of these findings considering the recent increase of global temperature and the challenge of breakdown of temperature sensitive resistance to some plant viruses is discussed.

The effect of supplemental 70% oxygen on postoperative nausea and vomiting in patients undergoing inguinal hernia surgery.

BACKGROUND: Postoperative nausea and vomiting (PONV) are among the leading side-effects after surgery performed under general anaesthesia. The role of oxygen as an important method for treatment of PONV was studied. The aim of this study was to compare intraoperative 30% oxygen with 70% oxygen for improvement of PONV in patients undergoing inguinal hernia surgery. METHODS: In a clinical double-blind study, patients (n=100) undergoing inguinal hernia surgery were given a standardized halothane anesthetic. After induction, they were randomly assigned to the following two groups: routine oxygen administration with 30% oxygen, balance nitrogen ("30% oxygen group," n=50) and supplemental oxygen administration with 70% oxygen, balance nitrogen ("70% oxygen group," n=50). The overall incidence of nausea and vomiting during the initial postoperative 24 h and correlation between arterial oxygen saturation and incidence of PONV was evaluated. RESULTS: There was significant difference in PONV incidence between the two studied groups (14.3% in group treated with 70% oxygen versus 40.0% in group treated with 30% oxygen, P<0.0001). There was a positive correlation between increase in arterial oxygen saturation and decrease in PONV incidence (P<0.0001). CONCLUSION: Supplemental oxygen effectively prevents postoperative nausea and vomiting after inguinal hernia surgery: the higher the arterial oxygen saturation, the less frequent PONV.