ALBINO AND PALE GREEN 10 Encodes BBMII Isomerase Involved in Histidine Biosynthesis in Arabidopsis thaliana

Abstract

We isolated an Arabidopsisalbino and pale green 10 (apg10) mutant which exhibits pale green cotyledons and true leaves at the juvenile stage. We identified a valine to leucine change in BBMII (N′-[(5′-phosphoribosyl)-formimino]-5-aminoimidazole-4-carboxamide ribonucleotide) isomerase involved in histidine biosynthesis. The morphological abnormality of apg10 was recovered by histidine supplementation. The histidine limitation induced by apg10 mutation causes dynamic changes of the free amino acid profile, suggesting the existence of a cross-pathway regulatory mechanism of amino acid biosynthesis in plants. We also revealed that the APG10 knockout mutant exhibited embryo lethality, indicating the essential role of the Arabidopsis BBMII isomerase for plant growth.