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Temperature controls on the basal emission rate of isoprene in a tropical tree Ficus septica : exploring molecular regulatory mechanisms
Author(s) -
Mutanda Ishmael,
Inafuku Masashi,
Saitoh Seikoh,
Iwasaki Hironori,
Fukuta Masakazu,
Watanabe Keiichi,
Oku Hirosuke
Publication year - 2016
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12797
Subject(s) - isoprene , biology , transcriptome , gene , biochemistry , gene expression , chemistry , botany , organic chemistry , copolymer , polymer
Abstract Isoprene emission from plants is very sensitive to environmental temperature both at short‐term and long‐term scales. Our previous study demonstrated suppression of isoprene emission by cold temperatures in a high emitting tropical tree Ficus septica and revealed a strong correlation of emission to isoprene synthase (IspS) protein levels. When challenged with decreasing daily temperatures from 30 to 12 °C, F . septica completely stopped isoprene emission at 12 °C, only to recover on the second day after re‐exposure to 30 °C. Here, we explored this regulation of isoprene emission in response to environmental temperature by a comprehensive analysis of transcriptome data, gene expressions and metabolite pools of the 2‐C‐methyl‐D‐erythritol 4‐phosphate (MEP) pathway. MEP pathway genes and metabolites dynamics did not support substrate‐level limitations as major control over observed basal emission, but transcriptome data, network inferences and putative regulatory elements on IspS promoter suggested transcriptional regulation of IspS gene through circadian rhythm and phytohormone signalling processes. Expression levels of 29 genes involved in these pathways were examined by quantitative real‐time PCR. We propose that temperature controls over basal isoprene emission at a time‐scale of hours to few days are regulated by phytohormone‐mediated transcriptional modulation of IspS gene under synchronization by the circadian clock.