FIGURE 2.

Regulatory modes of alternative splicing events during flowering transition. (A) Development and environmental regulation of alternative splicing. The alternative splicing patterns of the Arabidopsis FLM and the Brachypodium FT2 are modulated by temperature and plant aging signals, respectively, altering the molar ratios of alternatively spliced RNA isoforms. (B) Differential stability of the alternatively spliced protein isoforms of CO. While COα is targeted by the HOS1 and COP1 E3 ubiquitin ligases under red light and dark conditions, respectively, COβ is resistant to the ubiquitin-mediated degradation process. (C) Constitutive occurrence of alternative splicing in the autonomous flowering pathway. FCA is a central component of the autonomous flowering pathway. Its alternative splicing produces several transcript isoforms. It is currently unclear whether and how its alternative splicing is modulated by developmental cues or environmental stimuli.