Figure 1.

The MSH1 effect outlined in Arabidopsis. Plastidic and mitochondrial outcomes following MSH1 suppression and selection. Enhanced illegitimate recombination within the mitochondrial genome leads to substoichiometric shifting and expression of a male sterility trait. Lack of pollination in a CMS line can lead to low-frequency reversion to fertility, similarly involving MSH1 effects and mitochondrial subgenomic shifting. Depletion of MSH1 from the sensory plastid produces a variable stress-response phenotype that conditions transgenerational memory and enhanced stress tolerance. Memory line crossing or grafting with wild-type (WT) produces enhanced fitness traits (Epi). These effects are recapitulated across plant species, suggesting a role for MSH1 in plant adaptation.