AtFtsH4 perturbs the mitochondrial respiratory chain complexes and auxin homeostasis in Arabidopsis.

Mitochondrial AtFtsH4 protease is one of four inner membrane-bound FtsH proteases in Arabidopsis. We found that the loss of AtFtsH4 regulates Arabidopsis development and architecture by mediating the peroxidase-dependent interplay between hydrogen peroxide (H2O2) and auxin homeostasis. These morphological changes were correlated with elevated levels of both hydrogen peroxide and peroxidases, which suggested that ftsh4-4 plant was related to the oxidative stress, and that the architecture was caused by the auxin homeostasis perturbation. This view was supported by the expression levels of several auxin signaling genes and auxin binding and transport genes were decreased significantly in ftsh4-4 plants. Taken together, our data published in the May issue of Molecular Plant suggests a link between the lack of AtFtsH4 protease, oxidative stress,s and auxin homeostasis to regulate plant growth and development. However, the detail molecular mechanisms of AtFtSH4 regulating oxidation stress and auxin homeostasis is unclear. Here, we present evidence that the high level accumulated of H2O2 in ftsh4-4 may correlates with the decreased mitochondrial respiration genes. We also showed that the decreased auxin level and auxin transport may caused by the inhibition of mitochondrial respiratory chain complexes.