Very-long-chain fatty acids have an essential role in plastid division by controlling Z-ring formation in Arabidopsis thaliana.

Recent studies have showed the essential mechanisms for plastid division that have bacterial orthologues, such as FtsZ and Min system proteins; however, causal factors regulating plastid division in plant cells are poorly understood. Here, we show that plastid division is inhibited in Arabidopsis by reduced amounts of very-long-chain fatty acids (VLCFAs), which have an acyl chain length of more than 20 carbons and are used for cuticular wax formation. The number of amyloplasts and chloroplasts decreased in the mutant defective in VLCFA synthesis and in wild-type plants treated with an inhibitor of VLCFA synthesis. Although similar inhibition of plastid division was observed in transgenic plants that over-expressed PDV2 , one of the outer membrane proteins at the plastid division site, dot-like aggregates of FtsZ protein and disordered placement of multiple Z-rings were found in wild-type chloroplasts treated the inhibitor of VLCFA synthesis. Expression analysis showed that ARC3 , one of the Min system genes, was down-regulated under low VLCFA conditions. Our results indicate that VLCFAs or VLCFA-containing lipids have an essential role in plastid division by controlling Z-ring formation, showing a novel function of plant VLCFAs.