Introduction: High-throughput RNA sequencing (RNA-Seq) studies demonstrate that Alternative
Splicing (AS) is a widespread mechanism that enhances transcriptome diversity, particularly
in plants exposed to environmental stress. In an attempt to determine the transcriptome and AS patterns
of cabbage inbred line “HO” under Heat Stress (HS), RNA-Seq was carried out using HS-treated
and control samples. Genome-wide analysis indicated that AS is differentially regulated in response to
HS. The number of AS events markedly increased in HS-treated samples compared to the control.
Conclusion: We identified 1,864 genes, including Heat shock transcription factor (Hsf) and heat
shock protein (Hsp) genes, that exhibited >4-fold changes in expression upon exposure to HS. The enriched
Gene Ontology (GO) terms of the 1,864 genes included ‘response to stress/abiotic stimulus/
chemical stimulus’, among, which the genes most highly induced by HS encode small Hsps and
Hsf proteins. The heat-induced genes also showed an increased number of AS events under HS conditions.
In addition, the distribution of AS types was altered under HS conditions, as the level of Intron
Retention (IR) decreased, whereas other types of AS increased, under these conditions. Severe HSinduced
AS was also observed in Hsfs and Hsps, which play crucial roles in regulating heat tolerance.
Our results support the notion that AS of HS-related genes, such as HsfA2 and HsfB2a, are important
for heat stress adaptation in cabbage.