The Propensity of Pentatricopeptide Repeat Genes to Evolve into Restorers of Cytoplasmic Male Sterility

Abstract

Cytoplasmic male sterility (CMS) is a widespread phenotype in plants, which present a defect in the production of functional pollen. The male sterilizing factors usually consist of unusual genes or open reading frames encoded by the mitochondrial genome. CMS can be suppressed by specific nuclear genes called restorers of fertility (Rfs). In the majority of cases, Rf genes produce proteins that act directly on the CMS conferring mitochondrial transcripts by binding them specifically and promoting processing events. In this review, we explore the wide array of mechanisms guiding fertility restoration. PPR proteins represent the most frequent protein class among identified Rfs and they exhibit ideal characteristics to evolve into restorer of fertility when the mechanism of restoration implies a post-transcriptional action. Here, we review the literature that highlights those characteristics and help explain why PPR proteins are ideal for the roles they play as restorers of fertility.

Chromosome-scale genome assembly provides insights into rye biology, evolution, and agronomic potential

“…Members of the mitochondrial transcription TERmination Factor (mTERF) family are likely also involved in fertility restoration in cereals 51 . The repertoire of restorer genes is predicted to expand in outcrossing species 35,52 . We investigated this hypothesis by comparing RFL and mTERF gene counts between rye and several closely and distantly allied species including barley and the subgenomes of various wheat species.…”

Hybridization, sex specific genomic architecture and local adaptation

“…Negative effects associated with disruption of co-evolved mito-nuclear complexes e.g. on ageing [52,54] [60,61]. Suboptimal respiration is one of the fitness costs to hybrids in flycatchers [56], carnivorous mice [58], voles [62], and chickadees [63], likely due to mito-nuclear incompatibilities.…”

The RNA editing factor DUA1 is crucial to chloroplast development at low temperature in rice

“…However, little or no functional redundancy among PPR proteins has been found in higher plants, this situation indicates that the functions of PPR proteins are highly diversified in these plants. Accumulating evidence has revealed that PPR proteins are involved in a wide range of biological processes, such as cytoplasmic male sterility (CMS; Gaborieau et al ., ; Igarashi et al ., ; Liu et al ., , ), embryogenesis (Cai et al ., ; Li et al ., ; Tadini et al ., ), retrograde signaling (Sun et al ., ), and low temperature stress (Wu et al ., ; Wang et al ., ). However, the molecular mechanisms underlying the roles of PPR proteins in low temperature stress remain largely unknown.…”