Role of TCP transcription factors in cotyledon opening and expansion in response to light

VIOLA IVANA; GONZALEZ, DANIEL H; ALEM, ANTONELA L

Santa Fe

Congreso; XXXIII Argentinian meeting of Plant Physiology; 2021

Sociedad Argentina de Fisología Vegetal

After germination, exposure to light promotes the opening and expansion of the cotyledons and the development of the photosynthetic apparatus in a process called de-etiolation. This process is crucial for seedling establishment and photoautotrophic growth. TEOSINTE BRANCHED 1, CYCLOIDEA, and PROLIFERATING CELL FACTORS transcription factors (TCPs) proteins constitute a family of plant-specific transcription factors that control various processes of plant development such as embryogenesis, germination, and the morphogenesis of leaves and flowers. They also participate in the modulation of hormone signaling pathways, thus adjusting cellular processes to internal growth demands and signals received from the environment, as light and temperature. TCP proteins are divided into two classes, I and II. The TCP family contains 24 members in Arabidopsis, many of which have been shown to interact with transcription factors from other families. In this study, we identified GOLDEN2-LIKE 1 (GLK1), a key transcriptional regulator of photomorphogenesis, as a protein partner class I TCPs from Arabidopsis. We found that the class I protein TCP15 and GLK1 are jointly required for cotyledon opening and the induction of cell expansion and photosynthesis associated genes during de-etiolation of Arabidopsis seedlings. Our results suggest that the functional interaction between these transcription factors may serve to coordinate the execution of two distinct processes required for correct de-etiolation, i.e. cell expansion and the biogenesis of the photosynthetic apparatus.