Mitochondrial Energy Homeostasis and Membrane Interaction Regulate the Rapid Growth of Moso Bamboo

The rapid growth of moso bamboo is primarily attributed to the swift elongation of its internodes. While mitochondria are known to provide energy for various cellular processes, the specific mechanisms by which they facilitate rapid growth in bamboo remain elusive. In this study, we optimised the procedures for mitochondria isolation and performed a comprehensive analysis of mitochondrial dynamics and proteomics from internodes at various growth stages, including the initial growth (IG) stage, the starting of cell division (SD), and the rapid elongation (RE). Confocal observation demonstrated that cells in the RE stage have a higher mitochondrial density and increased mitochondrial motility compared to other stages. Proteomic analysis of isolated mitochondria revealed an upregulation of the tricarboxylic acid cycle, along with a synchronous increase in both mitochondrial- and nuclear-encoded components of oxidative phosphorylation in RE cells. Moreover, the upregulation of various mitochondrial membrane transporters in RE cells suggests an enhanced exchange of metabolic intermediates and inorganic ions with the cytosol. Intriguingly, ultrastructural analysis and pharmacological treatments revealed membrane interactions between the endoplasmic reticulum (ER) and mitochondria in RE cells. In conclusion, our study provides novel insights into mitochondrial function and the intracellular dynamics that regulate the rapid growth of moso bamboo.