Li Yong, Huang Jin, Song Fangyuan, Guo Zhiyue, Deng Wen
Cash Crops Research Institute, Hubei Academy of Agricultural Sciences, Wuhan 430064, China.
Genes (Basel). 2024 Dec 5;15(12):1571. doi: 10.3390/genes15121571.
The midday depression of photosynthesis, a physiological phenomenon driven by environmental stress, impacts plant productivity. This study aims to elucidate the molecular and physiological responses underlying midday depression in two mulberry species, Ewu No. 1 (Ew1) and Husan No. 32 (H32), to better understand their species-specific stress adaptation mechanisms. RNA-seq analysis was conducted on leaf samples collected at three time points (10:00 a.m., 12:00 p.m., and 4:00 p.m.), identifying 22,630 differentially expressed genes (DEGs). A comparative Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was performed to reveal the involvement of key metabolic and signaling pathways in stress responses. Ew1 displayed enhanced stress tolerance by upregulating genes involved in energy management, water conservation, and photosynthetic processes, maintaining higher photosynthetic rates under midday stress. In contrast, H32 adopted a more conservative response, downregulating genes related to photosynthesis and metabolism, favoring survival at the expense of productivity. The KEGG analysis highlighted starch and sucrose metabolism and plant hormone signaling as critical pathways contributing to these species-specific responses. Ew1's adaptive molecular strategies make it more suitable for environments with variable light and temperature conditions, while H32's conservative approach may limit its productivity. These findings provide valuable insights for breeding programs aimed at improving stress tolerance and photosynthetic efficiency in mulberry and other crops, particularly under fluctuating environmental conditions.
光合作用的午间降低是一种由环境胁迫驱动的生理现象，会影响植物生产力。本研究旨在阐明两个桑树种（鄂桑1号（Ew1）和湖桑32号（H32））午间降低背后的分子和生理反应，以更好地了解它们物种特异性的胁迫适应机制。对在三个时间点（上午10:00、中午12:00和下午4:00）采集的叶片样本进行了RNA测序分析，鉴定出22,630个差异表达基因（DEG）。进行了比较京都基因与基因组百科全书（KEGG）通路分析，以揭示关键代谢和信号通路在胁迫反应中的参与情况。Ew1通过上调参与能量管理、水分保持和光合过程的基因，表现出增强的胁迫耐受性，在午间胁迫下维持较高的光合速率。相比之下，H32采取了更保守的反应，下调与光合作用和代谢相关的基因，以牺牲生产力为代价来利于生存。KEGG分析突出了淀粉和蔗糖代谢以及植物激素信号传导是促成这些物种特异性反应的关键通路。Ew1的适应性分子策略使其更适合光照和温度条件多变的环境，而H32的保守方法可能会限制其生产力。这些发现为旨在提高桑树和其他作物胁迫耐受性和光合效率的育种计划提供了有价值的见解，特别是在环境条件波动的情况下。
