Role of ancestral retrograde signals in the regulation of Arabidopsis thaliana alternative splicing

ABALLAY, FEDERICO E; PETRILLO, EZEQUIEL

Mendoza

Congreso; LVIII Reunión Anual de SAIB; 2022

SAIB

Plant development and physiology depends on light. This environmental cue produces a massive changeon gene expression, regulating it at different scales such as alternative splicing. This mechanism mightbe regulated in nucleus by chloroplast (retrograde signal). On the one hand, it has been demonstratedthat TOR kinase is involved in light-induced retrograde signaling pathway in roots. On the other hand, it isvery well-known that chloroplasts are derived from free-living photosynthetic bacteria. In all bacteria,stringent control, which is activated by (p)ppGpp (alarmone) in response to nutritional deficit, regulatesgene expression. As bacteria, chloroplasts in land plants can synthesize the alarmone in response tostress. Alarmone levels are regulated by RelA-Spot homologue enzymes (RSHs) that are encoded in thenuclear genome and their expression is regulated by TOR kinase. Another plastid response is theformation of stromules (stroma-filled tubules). These tubules might exchange signals and metabolitesamong plastids and other cellular compartments. We aim to determine whether these signalingmechanisms are shared between bacteria and chloroplasts, as a control pathway able to modulatenuclear gene expression. Specifically, we will study how dark/light-induced alternative splicing regulationis affected by alarmone and stromules in Arabidopsis thaliana. We will establish reporter transgenic linesto correlate alarmone levels, stromules abundance and changes in alternative splicing patterns. We willdiscuss the preliminary data and try to establish how light and TOR kinase signals regulate alarmonelevels, stromules formation to modify alternative splicing.