PHYTOCROME-DEPENDENT TEMPERATURE PERCEPTION MODULATES ISOPRENOID METABOLISM IN TOMATO

DE LUCA, MB; BERMÚDEZ, L; ROSSI, M; BIANCHETTI, R; ROSADO, D; HASLAM, R; DE HARO, LA; MICHAELSON, L; CARRARI, F

Simposio; VII SIMPÓSIO BRASILEIRO DE GENÉTICA MOLECULAR DE PLANTAS; 2019

Changes in ambient temperature trigger massive alterations in primary and secondary plant metabolisms. Therefore, plants have acquired an intricate metabolic plasticity to adjust to temperature environmental changes. In Arabidopsis thaliana, temperature changes are sensed by phytochromes (PHYs) inactivating PHYB when temperature increases. In tomato (Solanum lycopersicum) PHYs belong to a multigenic family that encompasses five members: PHYA, PHYB1, PHYB2, PHYE, PHYF. Although several reports have described their role in controlling metabolic pathways in response to light, their function as thermosensors remains largely unknown. Here, we study isoprenoid metabolism in wild-type and phy mutant tomato plants grown under two contrastingtemperatures: 24º/18ºC and 30/24ºC. Results revealed that elevated temperatures led to the reduction in chlorophyll and carotenoids levels in leaves in a PHYB1/B2-mediated mechanism through the transcriptional regulation of methylerythritol 4-phosphate and chlorophyll degradation pathway enzyme encoding genes: DXS1, DXR, CMS, GGPS1, GGDR, CLH4, PPH, SGR-like, PAO and PES2. Similarly, in fruits, high temperature or PHY impairment in phyAB1B2 triple mutant led to the transcriptional downregulation of carotenoid biosynthetic genes (GGPS2, PSY1 and PDS) resulting in reduced amount of lycopene. Data presented here demonstrate the role of PHYs as thermosensorsmodulating isoprenoid metabolism in tomato.