@article{Liang2024, 
author = {Yonggui Liang and Chenyu Yang and Fangyan Ming and Bingwei Yu and Zhihua Cheng and Yixi Wang and Zhengkun Qiu and Xiaolan Zhang and Bihao Cao and Shuangshuang Yan},
title = {A bHLH transcription factor, CsSPT, regulates high-temperature resistance in cucumber},
year = {2024},
journal = {Horticultural Plant Journal},
volume = {10},
number = {2},
pages = {503-514},
keywords = {High temperature, Photosynthesis, Cucumber, bHLH, CsSPT},
url = {https://www.sciopen.com/article/10.1016/j.hpj.2023.02.005},
doi = {10.1016/j.hpj.2023.02.005},
abstract = {High-temperature stress threatens the growth and yield of crops. Basic helix-loop-helix (bHLH) transcription factors (TFs) have been shown to play important roles in regulating high-temperature resistance in plants. However, the bHLH TFs responsible for high-temperature tolerance in cucumbers have not been identified. We used transcriptome profiling to screen the high temperature-responsive candidate bHLH TFs in cucumber. Here, we found that the expression of 75 CsbHLH genes was altered under high-temperature stress. The expression of the CsSPT gene was induced by high temperatures in TT (Thermotolerant) cucumber plants. However, the Csspt mutant plants obtained by the CRISPR-Cas9 system showed severe thermosensitive symptoms, including wilted leaves with brown margins and reduced root density and cell activity. The Csspt mutant plants also exhibited elevated H2O2 levels and down-regulated photosystem-related genes under normal conditions. Furthermore, there were high relative electrolytic leakage (REC), malondialdehyde (MDA), glutathione (GSH), and superoxide radical (O2·−) levels in the Csspt mutant plants, with decreased Proline content after the high-temperature treatment. Transcriptome analysis showed that the photosystem and chloroplast activities in Csspt mutant plants were extremely disrupted by the high-temperature stress compared with wild-type (WT) plants. Moreover, the plant hormone signal transduction, as well as MAPK and calcium signaling pathways were activated in Csspt mutant plants under high-temperature stress. The HSF and HSP family genes shared the same upregulated expression patterns in Csspt and WT plants under high-temperature conditions. However, most bHLH, NAC, and bZIP family genes were significantly down-regulated by heat in Csspt mutant plants. Thus, these results demonstrated that CsSPT regulated the high-temperature response by recruiting photosynthesis components, signaling pathway molecules, and transcription factors. Our results provide important insights into the heat response mechanism of CsSPT in cucumber and its potential as a target for breeding heat-resistant crops.}
}