Analysis of stress-induced transcripts and biogenic volatile organic compound emissions in tropical hymenaea courbaril and coniferous pinus ponderosa

Changes in the composition of biogenic volatile organic compound (BVOC) emissions and stress-responsive gene transcripts were investigated in the tropical tree species Hymenaea courbaril and the coniferous species Pinus ponderosa. Heat stress and insect wounding have been associated with an increase in the release of stored and de novo synthesized BVOCs. These BVOCs are released into the atmosphere, where they can interact with nitrous oxides to create ozone and alter cloud properties via the formation of secondary organic aerosols (SOAs). To determine the source of the BVOCs being released (stored vs. de novo), we subjected both species (Ponderosa and Hymenaea) to heat stress and methyl jasmonate (MeJa) treatment. The temperature in the growth chamber containing the trees was increased from 24°C to 40°C (Ponderosa) or 27°C to 42°C (Hymenaea), and BVOCs were collected using leaf cuvette enclosures. Leaves were collected at 0 and 24 h for transcript analysis. Heat- and MeJa-responsive gene transcripts were detected using SeeGene's GeneFishing™ technology. These differentially expressed genes were then classified using BLAST analysis, and expression of 25 selected gene transcripts were examined by qPCR. These stress-inducible genes have potentials to be transferred to plants for trait enhancements.