Gene expression analysis of disabled and re-induced isoprene emission by the tropical treeFicus septicabefore and after cold ambient temperature exposure

• DOI: 10.1093/treephys/tpw032
• Publication Date: 2016-04-29T02:26:47Z
• Authors: Ishmael Mutanda; Seikoh Saitoh; Masashi Inafuku; Hiroaki Aoyama; Tomonori Takamine; Kazuhito Satou; Masako Akutsu; Kuniko Teruya; Hinako Tamotsu; Makiko Shimoji; Haruki Sunagawa; Hirosuke Oku
• Keywords: 0301 basic medicine; Tropical Climate; Alkyl and Aryl Transferases; Transcription, Genetic; Acclimatization; 15. Life on land; Ficus; Genes, Plant; Real-Time Polymerase Chain Reaction; Trees; Cold Temperature; 03 medical and health sciences; Hemiterpenes; Gene Expression Regulation, Plant; Stress, Physiological; 13. Climate action; Pentanes; Butadienes; Metabolic Networks and Pathways; Plant Proteins

Isoprene is the most abundant type of nonmethane, biogenic volatile organic compound in the atmosphere, and it is produced mainly by terrestrial plants. The tropical tree species Ficus septica Burm. F. (Rosales: Moraceae) has been shown to cease isoprene emissions when exposed to temperatures of 12 °C or lower and to re-induce isoprene synthesis upon subsequent exposure to temperatures of 30 °C or higher for 24 h. To elucidate the regulation of genes underlying the disabling and then induction of isoprene emission during acclimatization to ambient temperature, we conducted gene expression analyses of F. septica plants under changing temperature using quantitative real-time polymerase chain reaction and western blotting. Transcription levels were analyzed for 17 genes that are involved in metabolic pathways potentially associated with isoprene biosynthesis, including isoprene synthase (ispS). The protein levels of ispS were also measured. Changes in transcription and protein levels of the ispS gene, but not in the other assessed genes, showed identical temporal patterns to isoprene emission capacity under the changing temperature regime. The ispS protein levels strongly and positively correlated with isoprene emission capacity (R(2) = 0.92). These results suggest that transcriptional regulation of ispS gave rise to the temporal variation in isoprene emission capacity in response to changing temperature.