Arabidopsis seedlings treated by TPPOT and TPPST

We synthesized two new drugs, TPPOT and TPPST, which selectively localize to mitochondria and inhibit mitochondrial cytochrome C oxidase in a reversible manner. Treating Arabidopsis seedlings with the drugs led to stunted plant growth. The drugs changed the inner structure of mitochondria. Transcriptome analyses revealed that, to survive such energy deficiency, the plant turned down defense signaling, secondary metabolism, and photosynthesis; and relied on beta-oxidation in peroxisome to obtain building blocks. At the cellular level, mitophagy was strongly induced by drug treatment at 24 hours treatment. GFP-ATG8 was recruited to and surrounded mitochondria, followed by their mutual degradation in the vacuole. In addition, vacuole morphology significantly changed under high concentration of TPPST treatment and mitochondria accumulated in the vacuole. The expression of auxin transporter PIN2 dramatically declined when treated by the drugs. In summary, TPPOT and TPPST could be effective drugs to study the connection between mitochondria and intracellular transport in plants.