Alternative Splicing of Is Involved in the Improvement of Thermotolerance in Wheat.

High temperature has severely affected plant growth and development, resulting in reduced production of crops worldwide, especially wheat. Alternative splicing (AS), a crucial post-transcriptional regulatory mechanism, is involved in the growth and development of eukaryotes and the adaptation to environmental changes. Previous transcriptome data suggested that heat shock transcription factor (Hsf) may form different transcripts by AS. However, it remains unclear whether this post-transcriptional regulatory mechanism of is related to thermotolerance in wheat (). Here, we identified a novel splice variant, , which was induced by high temperature and played a positive role in thermotolerance regulation in wheat. Moreover, TaHsfA2-7-AS is predicted to encode a small truncated TaHsfA2-7 isoform, retaining only part of the DNA-binding domain (DBD). is constitutively expressed in various tissues of wheat. Notably, the expression level of is significantly up-regulated by heat shock (HS) during flowering and grain-filling stages in wheat. Further studies showed that TaHsfA2-7-AS was localized in the nucleus but lacked transcriptional activation activity. Ectopic expression of in yeast exhibited improved thermotolerance. Compared to non-transgenic plants, overexpression of in results in enhanced tolerance to heat stress. Simultaneously, we also found that TaHsfA1 is directly involved in the transcriptional regulation of and . In summary, our findings demonstrate the function of splicing variant in response to heat stress and establish a link between regulatory mechanisms of AS and the improvement of thermotolerance in wheat.