Location: Cereal Crops ResearchTitle: Map-based cloning of the Gpa1 gene regulating chloroplast biogenesis in barley
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/9/2021
Publication Date: 7/19/2021
Citation: Yang, S., Overlander, M., Fiedler, J.D. 2021. Map-based cloning of the Gpa1 gene regulating chloroplast biogenesis in barley [abstract]. Plant Biology Conference 2021. p.1082485.
Technical Abstract: Chloroplast biogenesis is critical for crop biomass and economic yield. However, chloroplast development is a very complicated process coordinated by cross-communication between the nucleus and plastids, and the underlying mechanisms have not been fully revealed. To explore the regulation machinery for chloroplast biogenesis, we conducted map-based cloning of the Grandpa 1 (Gpa1) gene regulating chloroplast development in barley. The spontaneous mutation gpa1.a caused a variegation phenotype of the leaf, dwarfed growth, and reduced grain yield. Genetic mapping anchored the Gpa1 gene onto 2H within a gene cluster functionally related to photosynthesis or chloroplast differentiation. One gene (HORVU.MOREX.r2.2HG0177270) in the delimited region encodes a putative plastid terminal oxidase (PTOX) in thylakoid membranes, which is homologous to IMMUTANS (IM) of Arabidopsis. The IM gene is required for chloroplast biogenesis and maintenance of functional thylakoids in Arabidopsis. Using CRISPR technology, we knocked out the PTOX-encoding gene and phenocopied the gpa1.a mutant. Therefore, HORVU.MOREX.r2.2HG0177270 is indeed the Gpa1 gene. Cloning of Gpa1 facilitates our understanding of molecular mechanisms underlying chloroplast biosynthesis, and it is indicated that the PTOX activity is conserved between monocots and dicots for the establishment of the photosynthesis factory.