Jiang Zeyu, Wang Di, Che Ye, Amanullah Sikandar, Zhang Ling, Jie Siyuan, Yang Wei, Wang Mingze, Wang Lina, Qi Guochao
Daqing Branch of Heilongjiang Academy of Agricultural Sciences, Daqing, China.
Department of Horticultural Science, North Carolina State University, Mountain Horticultural Crops Research, and Extension Center, 455 Research Drive, Mills River, North Carolina, United States of America.
PLoS One. 2025 Jun 25;20(6):e0326434. doi: 10.1371/journal.pone.0326434. eCollection 2025.
Hemp (Cannabis sativa L.) has a long cultivation history around the world. In northeast part of China, the alkaline soil geology severely reduces crop production. In this study, we tried to evaluate the impacts of alkali-induced stress on the photosynthetic status and physiological indices of hemp plants. The microscopic evaluation of endogenous ultrastructure clearly demonstrated significant oxidative damage to the structure of the photosynthetic tissues associated with the membrane, resulting from an increase in the levels of MGDG and DGDG. The deformed photosynthetic apparatus induced by alkali-stress significantly inhibited the biosynthesis process of photosynthetic pigments, causing 49.25%, 52.72%, 65.31%, and 28.13% loss in total Chl, Chl a, Chl b, and carotenoids, respectively. Meanwhile, the reduction in chlorophyll fluorescence parameters (Pn (74.62%), Gs (39.69%), and Tr (83.77%)) along with the obviously increased MDA (28.57%) and H2O2 (35.18%) content exhibited that the inhibitory effect of alkali-stress not only decreased the photosynthetic efficiency by intercepting the nutrient supply but also generated excessive ROS, resulting in oxidative stress. Transcriptomic analysis (RNA-sequencing) revealed the considerably enriched GO terms as well as KEGG pathways that exposed the significant DEGs. The qPCR expression evaluation of down-regulated chlorophyll biosynthesis-related major genes (GOGAT (LOC115699366) and HEMA (LOC133032634)) and photosystem-related major genes (PSB (LOC115701338) and HCF (LOC115707994)) exhibited important molecular evidence for modulating the photosynthesis activity of hemp plant under devastating mechanism of alkali-stress. However, the transcript patterns of photorespiration-related genes (GOX (LOC115697365) and GDC (LOC115707082)) showed a slower decreasing trend at late stress stage (at 24 ~ 48 h), and the transcription of SGAT gene (LOC115699360) was even enhanced by stress treatment at 48 h, probably in an attempt to adjust cellular carbon balance and elevate the antioxidant properties induced by alkali-stress.
大麻（Cannabis sativa L.）在世界各地有着悠久的种植历史。在中国东北地区，碱性土壤地质严重降低了作物产量。在本研究中，我们试图评估碱诱导胁迫对大麻植株光合状态和生理指标的影响。对内源超微结构的微观评估清楚地表明，由于MGDG和DGDG水平的增加，与膜相关的光合组织结构受到了显著的氧化损伤。碱胁迫诱导的光合机构变形显著抑制了光合色素的生物合成过程，导致总叶绿素、叶绿素a、叶绿素b和类胡萝卜素分别损失49.25%、52.72%、65.31%和28.13%。同时，叶绿素荧光参数（Pn（74.62%）、Gs（39.69%）和Tr（83.77%））的降低以及MDA（28.57%）和H2O2（35.18%）含量的明显增加表明，碱胁迫的抑制作用不仅通过阻断养分供应降低了光合效率，还产生了过量的活性氧，导致氧化应激。转录组分析（RNA测序）揭示了大量富集的GO术语以及KEGG通路，这些通路暴露了显著的差异表达基因。对下调的叶绿素生物合成相关主要基因（GOGAT（LOC115699366）和HEMA（LOC133032634））和光系统相关主要基因（PSB（LOC115701338）和HCF（LOC115707994））的qPCR表达评估显示了重要的分子证据，证明在碱胁迫的破坏机制下调节大麻植株光合作用活性。然而，光呼吸相关基因（GOX（LOC115697365）和GDC（LOC115707082））的转录模式在胁迫后期（24至48小时）显示出较慢的下降趋势，并且在48小时时，胁迫处理甚至增强了SGAT基因（LOC115699360）的转录，这可能是为了试图调节细胞碳平衡并提高碱胁迫诱导的抗氧化特性。
