INHERITANCE AND LINKAGE STUDIES WITH THE GRANDPA GENE IN BARLEY,<i>HORDEUM VULGARE</i>L.

Matchett, R. W.; Nass, H. G.; Robertson, D. W.

doi:10.1139/g71-074

Cited by 2 publications

(2 citation statements)

References 8 publications

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“…The gpa1.a mutation was originally identified in a spontaneous mutant of Barley cv Lyallpur, and a near‐isogenic line (NIL) of Bowman, BW397 displaying the variegation phenotype, was developed by backcrossing (Druka et al., 2011). Genetic mapping anchored Gpa1 onto the long arm of chromosome 2H within a gene cluster functionally related to photosynthesis or chloroplast differentiation (Druka et al., 2011; Matchett et al., 1971; Yang et al., 2021). However, the underlying gene for Gpa1 was not identified.…”

Section: Introductionmentioning

confidence: 99%

Plastid terminal oxidase is required for chloroplast biogenesis in barley

Overlander‐Chen,

Carlson,

Fiedler

et al. 2023

The Plant Journal

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SUMMARYChloroplast 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 regulatory 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, reduced grain yield, and increased tiller number. Genetic mapping anchored the Gpa1 gene onto 2H within a gene cluster functionally related to photosynthesis or chloroplast differentiation. One gene (HORVU.MOREX.r3.2HG0213170) 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 and gene transformation, we functionally validated that the PTOX‐encoding gene, HORVU.MOREX.r3.2HG0213170, is the causal gene of Gpa1. Gene expression and chemical analysis revealed that the carotenoid biosynthesis pathway is suppressed by the gpa1 mutation, rendering mutants vulnerable to photobleaching. Our results showed that the overtillering associated with the gpa1 mutation was caused by the lower accumulation of carotenoid‐derived strigolactones (SLs) in the mutant. The cloning of Gpa1 not only improves our understanding of the molecular mechanisms underlying chloroplast biosynthesis but also indicates that the PTOX activity is conserved between monocots and dicots for the establishment of the photosynthesis factory.

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Section: Introductionmentioning

confidence: 99%

Plastid terminal oxidase is required for chloroplast biogenesis in barley

Overlander‐Chen,

Carlson,

Fiedler

et al. 2023

The Plant Journal

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“…An allelism test and linkage study with morphological markers anchored the Gpa gene onto the long arm of chromosome 2 (2HL) [ 20 , 25 ]. However, the genetic control of the gpa mutants has not been investigated.…”

Section: Introductionmentioning

confidence: 99%

Genetic analysis of the barley variegation mutant, grandpa1.a

2021

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Background Providing the photosynthesis factory for plants, chloroplasts are critical for crop biomass and economic yield. However, chloroplast development is a complicated process, coordinated by the cross-communication between the nucleus and plastids, and the underlying biogenesis mechanism has not been fully revealed. Variegation mutants have provided ideal models to identify genes or factors involved in chloroplast development. Well-developed chloroplasts are present in the green tissue areas, while the white areas contain undifferentiated plastids that are deficient in chlorophyll. Unlike albino plants, variegation mutants survive to maturity and enable investigation into the signaling pathways underlying chloroplast biogenesis. The allelic variegated mutants in barley, grandpa 1 (gpa1), have long been identified but have not been genetically characterized. Results We characterized and genetically analyzed the grandpa1.a (gpa1.a) mutant. The chloroplast ultrastructure was evaluated using transmission electron microscopy (TEM), and it was confirmed that chloroplast biogenesis was disrupted in the white sections of gpa1.a. To determine the precise position of Gpa1, a high-resolution genetic map was constructed. Segregating individuals were genotyped with the barley 50 k iSelect SNP Array, and the linked SNPs were converted to PCR-based markers for genetic mapping. The Gpa1 gene was mapped to chromosome 2H within a gene cluster functionally related to photosynthesis or chloroplast differentiation. In the variegated gpa1.a mutant, we identified a large deletion in this gene cluster that eliminates a putative plastid terminal oxidase (PTOX). Conclusions Here we characterized and genetically mapped the gpa1.a mutation causing a variegation phenotype in barley. The PTOX-encoding gene in the delimited region is a promising candidate for Gpa1. Therefore, the present study provides a foundation for the cloning of Gpa1, which will elevate our understanding of the molecular mechanisms underlying chloroplast biogenesis, particularly in monocot plants.

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INHERITANCE AND LINKAGE STUDIES WITH THE GRANDPA GENE IN BARLEY,HORDEUM VULGAREL.

Cited by 2 publications

References 8 publications

Plastid terminal oxidase is required for chloroplast biogenesis in barley

Plastid terminal oxidase is required for chloroplast biogenesis in barley

Genetic analysis of the barley variegation mutant, grandpa1.a

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