CMS
Gobron N, Waszczak C, Simon M, Hiard S, Boivin S, Charif D, Ducamp A, Wenes E & Budar F 2013 A cryptic cytoplasmic male sterility unveils a possible gynodioecious past for Arabidopsis thaliana. PLoS ONE 8:e62450.
- we found cryptic CMS in the model plant Arabidopsis thaliana after crossing distantly related accessions
- male sterility resulted from an interaction between the Sha cytoplasm and two Mr-0 genomic regions located on chromosome 1 and chromosome 3
- we identified a novel mitochondrial ORF, named orf117Sha, that is most likely the sterilizing factor of the Sha cytoplasm
- we also report the coexistence of the sterilizing cytoplasm with a non-sterilizing cytoplasm at a small, local scale in a natural population
- a correlation between cytotype and nuclear haplotype was detected in this population
- this CMS system induced sexual polymorphism in A. thaliana populations, at the time when the species was mainly outcrossing
- restorer alleles are present across a wide diversity of genotypes
- the sterilizing cytoplasm is restricted to a single nuclear diversity group
- in the reported cases of Mimulus and Helianthus cryptic CMS, the sterilizing cytoplasms are rare and mostly restricted to unique populations, whereas nuclear restorers are common
- several explanations are evoked for this observation:
- ecological restriction of the spread of the sterilizing cytoplasm, but not for that of Rf genes
- the Rf genes predate the sterilizing cytoplasm
- in the case of the Ogura CMS system in wild radish, the cytoplasm had lost its sterilizing capacity, probably after the spread of Rf genes, resulting in hermaphroditic European populations with frequent restorers but devoid of sterilizing cytoplasm
- this knowledge will also allow investigating whether present-day maintainers are ancestral alleles or derived from restorers
