2026-08-05 中国科学院（CAS）
中国科学院西双版納熱帯植物園（XTBG）などの研究チームは、ヨーロッパナラの1枚の葉でも、表面と裏面がまったく異なる微生物生息環境として機能することを明らかにした。ドイツ中部の混交林で春から秋まで同一個体・同一葉を継続調査し、16S rRNA解析と葉の濡れやすさ、色素量、気孔分布などを組み合わせて分析した。その結果、日光・紫外線・風にさらされる葉表面では、環境ストレスに強い細菌群が優勢だった。一方、日陰で湿潤な裏面では、糖発酵性細菌や昆虫関連細菌など、植物や昆虫との相互作用に適した微生物が多かった。さらに、表面の微生物群集は季節を通じて比較的安定していたのに対し、裏面では植物の生理状態の変化に伴って強い季節変動が生じ、秋には多様性が低下した。葉を一つの均質な生息環境として扱う従来の研究では見落とされていた「葉内の微小環境の不均一性」が、植物―微生物相互作用を理解する重要な軸であることを示す成果である。
＜関連情報＞
- https://english.cas.cn/newsroom/research-news/202608/t20260805_1186898.shtml
- https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.71483
葉の表裏表面に存在する細菌群集は、季節によって異なる反応パターンを示す Bacterial communities on upper and lower leaf surfaces show distinct seasonal response patterns
Xiangbo Yin (尹相博), Lirey Ramirez, Christian Lampei, Hamed Azarbad, Dominik Greif, Eric Martiné, Changqing Liu, Fanhao Kong, Lee Ping Ang, …
New Phytologist Published: 02 August 2026
DOI:https://doi.org/10.1111/nph.71483
Summary
- Leaf surfaces represent one of the largest microbial habitats on Earth, which can be divided into upper and lower leaf surfaces. Upper and lower leaf surfaces offer contrasting microenvironments that vary through the seasons. This variation has rarely been quantified; however, in spite of it being highly relevant for leaf–microbiome contributions to terrestrial ecosystems, especially forests.
- To address this gap, we tracked bacterial communities on both surfaces of the same pooled leaves of Quercus robur in situ from spring to autumn, using genetically identical ramets to control host and genotypic variation. We combined 16S rRNA sequencing with analyses of leaf structural and physiological traits to link bacterial taxonomic, phylogenetic, and assembly characteristics.
- The two surfaces hosted distinct bacterial communities whose divergence intensified through the growing season. Upper-surface bacterial diversity remained relatively stable and was mainly associated with dynamic leaf traits, whereas lower-surface communities showed faster compositional and assembly-related shifts and were associated with both dynamic and stable leaf traits.
- These contrasting seasonal patterns reveal that within-leaf heterogeneity represents a fundamental axis of variation for bacterial seasonal dynamics, providing new insight into how microhabitat structure and host traits jointly shape phyllosphere functioning.
