ORGANELLE-DERIVED SIGNALS CONTROL ALTERNATIVE SPLICING IN ARABIDOPSIS THALIANA VIA TOR KINASE

RIEGLER, STEFAN; KUBACZKA, M. GUILLERMINA; BRUNKARD, JACOB O.; PETRILLO, EZEQUIEL; SERVI, LUCAS; GODOY HERZ, MICAELA A.; MEYER, CHRISTIAN; BARTA, ANDREA; SCARPIN, M. REGINA; VENHUIZEN, PETER; KALYNA, MARIA

Congreso; SAIB-SAMIGE Reunión Conjunta (LVII SAIB Meeting - XVI SAMIGE Meeting); 2021

SAIB

Light is the source of energy and the most relevant regulator of growth and adaptations in plants. This environmental cueinduces vast changes in gene expression at various levels, including alternative splicing. Light-triggered chloroplast retrogradesignals control alternative splicing in Arabidopsis thaliana. Now, we provide evidence that light regulates the expression of acore set of splicing-related factors in roots. Furthermore, alternative splicing responses in roots are not directly driven by lightbut are instead most likely triggered by photosynthesized sugars. The target of rapamycin (TOR) kinase plays a key role inthis shoot-to-root signaling pathway. Knocking down TOR expression or pharmacologically inhibiting TOR activity disruptsthe alternative splicing responses to light and exogenous sugars in roots. Consistently, splicing decisions are modulated bymitochondrial activity in roots. In conclusion, by activating the TOR pathway, sugars act as mobile signals to coordinatealternative splicing responses to light throughout the whole plant. We are currently trying to understand how TOR modulatesnuclear splicing decisions.