トマトの光合成におけるカリウムの調節機構を解明（Study Reveals How Potassium Regulates Photosynthesis in Tomatoes）

2026-03-31 中国科学院（CAS）

＜関連情報＞

• https://english.cas.cn/newsroom/research-news/202603/t20260331_1154896.shtml
• https://onlinelibrary.wiley.com/doi/10.1111/tpj.70784

カリウムは、解剖学的変異ではなく遺伝子調節を介してトマトの光合成効率を調節する Potassium mediates photosynthetic efficiency in tomato through genetic regulation rather than anatomical variation

Yi-Yun Li, Xiao-Qian Wang, Ming-Ying Yang, Dou Zuo, Hai-Cui Luo, Yu-Wen Zhang, Wei Huang
The Plant Journal  Published: 09 March 2026
DOI:https://doi.org/10.1111/tpj.70784

SUMMARY

Potassium (K) is classically viewed as a guard-cell osmoticum, yet its influence on the photosynthetic efficiency under steady-state and fluctuating light remains unresolved. We combined gas exchange, cellular anatomy, and transcriptomic profiling to explore how K deficiency limits CO₂ assimilation (A_N) in tomato (Solanum lycopersicum). Contrasting our expectations, the decline of A_N and mesophyll conductance (g_m) under K deficiency in tomato was not attributed to alternation of leaf and cellular anatomy but was linked to downregulation of carbonic anhydrases and plasma-membrane aquaporins that facilitate CO₂ diffusion. The maximum carboxylation rate of Rubisco (V_cmax) declined in parallel, coinciding with the repression of Rubisco small-subunit genes and Rubisco activase. Under fluctuating light, K deficiency significantly slowed stomatal opening and accelerated stomatal closure, increasing potential loss of CO₂ fixation after transition from low to high light. Transcript data implicated K-transport, anion-channel, and sugar-transporter genes as the molecular brakes. Therefore, leaf K content influences photosynthesis by regulating diffusional and biochemical capacities. These findings highlight the importance of K in photosynthesis under both stable and variable light environments, offering new targets for improving crop photosynthetic resilience.