The splicing factor RS31 regulates seed germination and flowering time in Arabidopsis thaliana.

CARTAGENA, CARLA M.; RODRÍGUEZ, FLORENCIA S.; SERVI, LUCAS; KALYNA, MARIA; PETRILLO, EZEQUIEL; TOGNACCA, ROCÍO S.

Mendoza

Congreso; LVIII Reunión Anual de SAIB; 2022

SAIB

Environmental signals such as light and temperature shape the plant transcriptome byimpacting on each possible level of gene expression. Alternative splicing (AS)significantly modulates the transcriptome, and to some extent the proteome, duringdevelopment and in response to environmental cues. The regulation of AS depends onthe expression level and post-translational modification of serine/arginine-rich (SR)proteins and other splicing factors. We have previously shown that when Arabidopsisseeds receive a pulse of Red light (Rp), the AS pattern of 226 genes associated withmRNA processing, RNA splicing, and mRNA metabolic processes, including thesplicing factor RS31, are drastically changed. Interestingly, these AS events areregulated by R and Far-Red light, although not directly associated with the propensityof the germination response, suggesting that AS is a source of gene expressionvariability, and that it is a necessary mechanism for plants to adapt to a changingenvironment. Here, we show that the overexpression of the RS31 coding isoform(namely mRNA1) promotes germination even under suboptimal light conditions.Moreover, the mRNA1 isoform abolishes light-induced alternative splicing changes ofsome genes (i.e., U2AF65A, DRM1) when compared to wild type seeds. These datasuggest that RS31 functions during light-induced seed germination in Arabidopsis andthat the striking impact on germination of the AS outcomes could be a relevantmechanism underlying seed physiology. We also show that mRNA1 overexpressionlines have a delayed flowering time and, accordingly, FLOWERING LOCUS C (FLC)and other flowering genes (i.e., FCA) have altered expression levels in these plantswhen compared to the wild type, suggesting that RS31 is involved in the regulation offlowering. Hence, affecting splicing, potentially through FLC, may also alter keyphysiological traits.