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 tem-peratures 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 degrees C and 32 degrees 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 hepta-nal, represented the maximum abundance in R plants compared to S plants at earlier times especially, 48 hpi/ 20 degrees C. Also, at 32 degrees 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 degrees C and 32 degrees C. Although, at 20 degrees C, they were activated at an earlier time. At 32 degrees 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 degrees 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.

Automated summary

This study investigated 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) in wheat cultivars. The results showed that VOCs in the leaves of resistant (R) and susceptible (S) cultivars responded differently to WSMV and temperature changes. Several metabolic pathways and compounds were up-regulated in R plants, especially at an earlier time and at elevated temperatures. The lipoxygenase pathway played an important role in increasing vector attractiveness and tolerance to biotic and abiotic stresses. The results emphasize the importance of understanding the synchronized regulation of defense-related VOCs for plant resistance to viruses and heat stress.