TCP14 and TCP15, new actors involved in temperature-dependent developmental responses in Arabidopsis.

GONZALEZ, DANIEL; VIOLA, IVANA; FERRERO, LUCÍA

CABA

Simposio; Fronteras en Biociencias III; 2018

As sessile organisms, plants usually modify their development in response to changing environmental conditions. A rise in ambient temperature, for example, causes the so-called thermomorphogenic response, which consists in an increase in hypocotyl and petiole elongation, among other processes. One of the master regulators of thermomorphogenesis is the basic helix-loop-helix (bHLH) transcription factor PHYTOCHROME INTERACTING FACTOR 4 (PIF4), a member of the small PIF family involved in developmental responses to changing light environments. TEOSINTE BRANCHED 1, CYCLOIDEA, PCF (TCP) transcription factors are involved in several aspects of plant development, modulating cell differentiation, proliferation and growth. These proteins contain a highly conserved domain, the TCP domain, responsible for DNA binding and protein-protein interactions. Based on sequence homology, they can be grouped into two major classes, I and II. In the present study, we show that mutants in the TCP transcription factor genes TCP14 and TCP15 have a deficient elongation response of petioles and hypocotyls to high temperature. Our results indicate that the Arabidopsis class I proteins TCP14 and TCP15 participate in elongation responses related to an increase in ambient temperature in close connection with the master regulator PIF4. The TCPs functionally interact with pathways regulated by PIF4 and directly participate in the induction of genes involved in gibberellin biosynthesis and cell expansion by high temperature. In this way, they integrate into the complex pathway that leads to the developmental response of plants to a rise in temperature.