Lu Mengnan, Wang Shiyan, Zhou Yonghong, Wang Xiaona, Su Hao, Gong Yanbing, De Ji
Key Laboratory of Biodiversity and Environment on the Qinghai-Tibetan Plateau, Ministry of Education, School of Ecology and environment, Xizang University, Lhasa, 850000, China.
School of Ecology and environment, Xizang University, Lhasa, Xizang, China.
BMC Plant Biol. 2025 Aug 22;25(1):1118. doi: 10.1186/s12870-025-07153-x.
Ephedra species, important Tibetan medicinal plants, are widely distributed across the Qinghai-Tibet Plateau at altitudes of 2700-5000 m. Their adaptation to high-altitude environments, such as low temperatures, strong UV radiation and low oxygen, is still poorly understood. This study investigated the morphological, metabolic, and genetic mechanisms underlying the reproductive advantage of a unique single-seed variant observed in high-germination-rate Ephedra species. Seeds from six Ephedra species were collected for germination assays and electron microscopic analysis. Results showed that E. saxatilis, E. intermedia, and E. monosperma exhibited significantly higher germination rates (Germination rates > 65%) and predominantly produced single-seed variants, while others mainly produced double seeds. Analysis of burr and fold numbers of phenotypic traits showed a significant positive correlation with germination rates. Time-course metabolomics analysis identified 762 KEGG annotated metabolites, and revealed E. saxatilis as the dominant species due to its faster metabolic rate, particularly simulated high-altitude conditions. Absolute hormone quantification highlighted the single-seed variant of E. saxatilis as the dominant type, with ABA content peaking in the shed seed coat. ABA exhibited antagonistic interactions with 2MeScZR, SA, IAA, GA7, IPR, and t-CA, suggesting a complex hormonal regulation network. Co-expression network analysis integrating transcriptome and hormone data predicted 23 key genes regulating seed germination adaptation. This study provides novel insights into the ecological and evolutionary significance of single-seed variation in high-altitude adaptation. The findings have potential applications in high-altitude plant breeding, conservation, and sustainable utilization of Ephedra species. Future research should focus on the genetic basis of single-seed variation and its role in other high-altitude plant species.
麻黄属植物是重要的藏药植物，广泛分布于青藏高原海拔2700 - 5000米的地区。它们对高海拔环境（如低温、强紫外线辐射和低氧）的适应机制仍知之甚少。本研究调查了在高发芽率麻黄属植物中观察到的一种独特的单粒种子变异体具有繁殖优势的形态、代谢和遗传机制。收集了六种麻黄属植物的种子进行发芽试验和电子显微镜分析。结果表明，山岭麻黄、中麻黄和单子麻黄表现出显著更高的发芽率（发芽率>65%），并且主要产生单粒种子变异体，而其他种类主要产生双粒种子。对表型性状的毛刺和褶皱数量分析表明与发芽率呈显著正相关。时间进程代谢组学分析鉴定出762种经KEGG注释的代谢物，并揭示山岭麻黄是优势种，因为其代谢速率更快，特别是在模拟高海拔条件下。绝对激素定量突出显示山岭麻黄的单粒种子变异体是主要类型，脱落种皮中的脱落酸含量达到峰值。脱落酸与2-甲硫基玉米素核苷、水杨酸、吲哚乙酸、赤霉素7、异戊烯基腺嘌呤和反式肉桂酸表现出拮抗相互作用，表明存在复杂的激素调控网络。整合转录组和激素数据的共表达网络分析预测了23个调控种子萌发适应的关键基因。本研究为高海拔适应中单粒种子变异的生态和进化意义提供了新的见解。这些发现对高海拔植物育种、麻黄属植物的保护和可持续利用具有潜在应用价值。未来的研究应关注单粒种子变异的遗传基础及其在其他高海拔植物物种中的作用。
