Decreased Vascular Bundle 1 affects mitochondrial and plant development in rice.

BACKGROUND: Mitochondria are vital regulators of plant growth and development, constitute the predominant source of ATP, and participate in multiple anabolic and catabolic metabolic pathways. But the mechanism by which dysfunctional mitochondria affect plant growth remains unknown, and more mitochondria-defective mutants need to be identified. RESULTS: A mitochondria-defective mutant decreased vascular bundle 1 (dvb1) was isolated from rice mutant library mutagenized by EMS (ethylmethane sulfonate), which shows dwarfism, narrow leaves, short branches, few vascular bundles, and low fertility. Map-based cloning, genetic complementation, and phylogenetic analysis revealed that DVB1 encodes a structural protein classified in the Mic10 family and is required for the formation of cristae in mitochondria, and was primarily expressed in vascular bundles. The DVB1 protein is partially localized in the mitochondria and capable of forming dimers and polymers. Comparing with the wild type, disruption of amino acid metabolism and increased auxin synthesis were observed in dvb1 mutant which also showed increased sensitivity to the mitochondrial electron transport inhibitors. CONCLUSIONS: DVB1 belongs to Mic10 family and DVB1 is partially localized in the mitochondria. Further studies indicated that DVB1 is important for mitochondrial and plant development in rice.