2026-06-22 中国科学院（CAS）
＜関連情報＞
- https://english.cas.cn/newsroom/cas-in-media/202606/t20260622_1174358.shtml
- https://www.cell.com/cell/abstract/S0092-8674(26)00642-2
タンパク質凝縮物による葉緑体の紫外線遮断は、強い光に対する耐性を付与する Chloroplast sunscreening by protein condensates confers high-light tolerance
Ning Shao ∙ Mingjiang Chen ∙ Ning Xu ∙ … ∙ Yuqiang Jiang ∙ Zheng Zhou ∙ Jiayang Li
Cell Published:June 17, 2026
DOI:https://doi.org/10.1016/j.cell.2026.05.042
Graphical abstract
Highlights
- Conserved MBS1 with ZnF and IDRs preferentially senses singlet oxygen in chloroplasts
- ¹O₂ induces MBS1 phase transition to form chloroplast-protective condensates
- MBS1 condensates attenuate excess light penetration and prevent chloroplast photodamage
- OsMBS overexpression enhances high-light tolerance and rice yield in 4-year field trials
Summary
Sunlight fuels life but generates singlet oxygen (1O2), which causes photodamage and triggers signaling and antioxidative defense pathways in chloroplasts where photosynthesis takes place. How cells sense 1O2 and instantaneously mount photoprotection remains elusive. Here, we show that a key mediator of 1O2 responses, METHYLENE BLUE SENSITIVITY1 (MBS1), is conserved from plants to animals and comprises a zinc-finger (ZnF) domain flanked by intrinsically disordered regions. MBS1 plays a critical role in ¹O₂ sensing through ZnF conformational change and phase transition from liquid-like droplets to lower-dynamic condensates. These chloroplast-associated condensates under high light attenuate light penetration to shield chloroplasts from photodamage. In rice, MBS1-overexpressing lines exhibit enhanced high-light tolerance and yield in 4-year field trials. Our findings uncover a “sunscreening” mechanism via MBS1 condensates that confer chloroplast photoprotection, highlighting its value for improving rice yields in the field under high-light stress exacerbated by climate change.
