Gene expression analysis of wheat (Triticum aestivum L.) during the vegetative stage under high ambient temperature condition

This study was conducted to acquire a comprehensive understanding of the growth characteristics of winter wheat in the Republic of Korea (ROK). The specific focus was on investigating physiological responses to temperature during the vegetative stages. We implemented four different temperature conditions, ranging from an average of 17 to 26 °C, in a climate-controlled growth chamber. We traced the 19 representative genes responsive to ambient high temperatures and heat stress. Hsp90.1-A1, HSP101 and MYB73 exhibited an increase in response to the rising temperature. Other genes such as ELF3, PIF4, VRNA1, SKP1 and HsfA1b decreased under high-temperature conditions. However, many transcription factors responding to high temperatures and genes related to the cell division cycle showed fluctuating expression, suggesting the presence of an optimal temperature within the range of 17 to 26 °C. Among them, Hsp90.1-A1, HSP101, YUCCA2, and MYB73 manifested significant differences in expression between 23 and 26 °C at 50 DAT, where a critical limit temperature of heat tolerance and heat stress may exist; therefore, these genes may be helpful as the probe to check the heat-related characteristics in wheat breeding. There are regional limitations, where the average temperature during the cultivation season is below 26 °C. The optimal range is between 20 and 23 °C, and the degree of activity during early vegetative growth becomes a vital trait for ensuring stable wheat production. This trait is anticipated to pose a challenging target for future wheat breeding in the Republic of Korea.