Study of Alternative Splicing Events in Maize Transcriptome Under Abiotic Stress

Alternative splicing (AS) plays an important role during plants’ development particularly when they are under stresses. To assess how different kinds of stresses intact impact AS in maize, we assembled and analyzed the transcript isoforms from 53 stress-relative RNA-Seq libraries of osmotic, salt, heat, cold, water flooding and UV treated samples. The resulting isoforms from different samples were mostly intron retention and alt-acceptor ones. Besides, the transcriptome under stresses would consist of more isoforms per gene. The numbers of isoforms per gene would more diverse among samples under the stressed treatment than under the control, indicating that plants would respectively adjust for stressed conditions through AS. There were also more splicing junction sites being detected in the stressed samples than in the controlled samples. We further classified isoforms into 4 types including known transcripts, novel transcripts of known genes, intergenic transcripts and others. They contributed 41%, 43%, 11% and 3.65% to all isoforms, respectively. GO analysis of significantly differentially expressed (DE) isoforms showed that the function of DE known isoforms are more related to response to stimulus or stress, whereas the function of DE novel isoforms of known genes are more related to metabolic process. In conclusion, different behaviors of AS observed in different stress conditions indicates that self-defensive mechanisms may be independently triggered in plants to accommodate stressed conditions.