In tune with power: Mitochondrial regulation of energy with TOR

As seedlings grow, they continuously fine-tune the balance between plant growth and energy consumption for better plant fitness. Mitochondria are essential to generate energy. Here, Canal et al. generated single mutants for a gene involved in the mitochondrial respiratory chain – CYTOCHROME C-1 (CYTC-1), which caused defective mitochondrial energy production, membrane potential, lower ATP content, and a reduced growth rate in the cytc-1 mutants.  Some of the mutant phenotypes resemble those of plants with abnormal Target of Rapamycin (TOR) signaling. TOR is a protein that integrates growth-related processes in all eukaryotes. The authors showed that TOR activity is impaired in the cytc-1 mutants. In contrast, TOR overexpression rescued the seedling growth and low ATP level of cytc-1 mutant. The authors conclude that plants can coordinate their metabolism in response to the disruption of the mitochondrial function in the cytc-1 mutation, which anticipates energy exhaustion and  speculates that conditions by reducing TOR activity levels and slowing growth. This study also sheds light on how mitochondria communicate their status to the rest of the cell. (Summary by Yueh Cho @YuehCho1984) New Phytol. 10.1111/nph.19506.