LIGHT REGULATION OF ALTERNATIVELY SPLICED GENES DURING ARABIDOPSIS THALIANA SEED GERMINATION

SAURA SANCHEZ MT; PETRILLO E; TOGNACCA RS; YANOVSKY MJ; SERVI L; BOTTO JF

Monterrey, California

Congreso; 12th Triennial Conference of The International Society for Seed Science.; 2017

International Society of Seed Science

Light is one of the most important factors regulating seed germination, plant growth and development. Light-sensing photoreceptors tightly regulate gene expression to control photomorphogenic responses. Although many levels of gene expression are modulated by photoreceptors, it is still unknown the importance of alternative splicing (AS) in the promotion of seed germination by light. During the last years consecutive reports demonstrated a steadily increasing percentage of alternatively spliced genes in plants. AS can lead to different outcomes and can produce transcripts that code for proteins with altered or lost function. Several examples have demonstrated AS functional importance in various processes like photosynthesis, defense responses, the circadian clock, hormone signaling, flowering time and metabolism. The aim of this work is to study the transcriptome and alternatively spliced genes expressed during light induction of seed germination in Arabidopsis thaliana. We evaluated the effect of R/FR (red/far red) light on AS in light-induced Col-0 seeds using high-throughput RNA sequencing (RNA-seq). We found that a Rp (red pulse) compared to a FRp (far red pulse) given after cold stratification, affects the AS of 226 genes. Some of these AS events were associated with genes involved in mRNA processing, RNA splicing and mRNA metabolic processes. We validated by RT-PCR these light-induced changes in the AS of genes that are involved in RNA splicing. Moreover, using a combination of R/FR light and phytochrome mutants approach, we showed that light modulates the AS pattern of some of these genes, i.e.: U2AF65 (an auxiliary splicing factor) and DOG1 (a seed dormancy gene), in a phytochrome B exclusive manner. Our results demonstrate that in Arabidopsis seeds (1) R/FR light triggers AS changes in different genes and, in some cases, (2) light exerts its effects through the action of phytochrome B. We conclude that AS is a source of gene expression diversity for proteins involved in the promotion of seed germination by light.