RS31: a novel player involved in the regulation of light-induced seed germination and flowering in Arabidopsis thaliana

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

Rosario

Congreso; XXXIV Argentinian Meeting of Plant Physiology RAFV Conference 2023; 2023

Sociedad Argentina de Fisiología Vegetal

Seed dormancy is a developmental checkpoint that prevents mature seeds from germinating under conditions that are otherwise favorable, allowing plants to regulate when and where they grow. Primary dormancy refers to the innate dormancy possessed by seeds when they are dispersed from the mother plant. Temperature and light are the most relevant environmental factors that regulate seed dormancy and germination. These environmental cues, that can trigger molecular and physiological responses (including ABA and GA signaling), induce a massive reprogramming of gene expression, and shape the seed transcriptome by affecting each possible level of gene expression such as mRNA splicing, translation, and stability. The expression of many genes that regulate dormancy, germination and flowering can be modulated by alternative splicing (AS, a co-transcriptional mechanism that generates transcriptome diversity) in response to the environment. We have previously shown that when Arabidopsis seeds receive a pulse of Red light, the AS pattern of the splicing factor RS31 is drastically changed. Here, we show that seeds overexpressing the RS31 coding isoform (namely mRNA1) do not show primary dormancy and germinate even under suboptimal light conditions, suggesting that mRNA1, ergo the RS31 protein, has a key role during the establishment of primary dormancy and functions during light-induced seed germination. Accordingly, ABA- and GA-related genes have altered expression levels. We also show that overexpression of the mRNA1 delays flowering under SD and LD conditions when compared to the wild type, suggesting that RS31 is also involved in the regulation of this process. Overall, affecting alternative splicing may also alter key physiological traits.