The Barley Chloroplast Mutator (<i>cpm</i>) Mutant: All Roads Lead to the <i>Msh</i>1 Gene
The barley chloroplast mutator (<i>cpm</i>) is a nuclear gene mutant that induces a wide spectrum of cytoplasmically inherited chlorophyll deficiencies. Plastome instability of <i>cpm</i> seedlings was determined by identification of a particular landscape of polymorphisms th...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-02-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/23/3/1814 |
| Summary: | The barley chloroplast mutator (<i>cpm</i>) is a nuclear gene mutant that induces a wide spectrum of cytoplasmically inherited chlorophyll deficiencies. Plastome instability of <i>cpm</i> seedlings was determined by identification of a particular landscape of polymorphisms that suggests failures in a plastome mismatch repair (MMR) protein. In Arabidopsis, <i>MSH</i> genes encode proteins that are in charge of mismatch repair and have anti-recombination activity. In this work, barley homologs of these genes were identified, and their sequences were analyzed in control and <i>cpm</i> mutant seedlings. A substitution, leading to a premature stop codon and a truncated MSH1 protein, was identified in the <i>Msh</i>1 gene of <i>cpm</i> plants. The relationship between this mutation and the presence of chlorophyll deficiencies was established in progenies from crosses and backcrosses. These results strongly suggest that the mutation identified in the <i>Msh</i>1 gene of the <i>cpm</i> mutant is responsible for the observed plastome instabilities. Interestingly, comparison of mutant phenotypes and molecular changes induced by the barley <i>cpm</i> mutant with those of Arabidopsis <i>MSH</i>1 mutants revealed marked differences. |
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| ISSN: | 1661-6596 1422-0067 |