A mitochondria-targeted PPR protein restores cytoplasmic male sterility by post-transcriptional modification of ORF147 in Cajanus cajanifolius

Restoration factors (Rfs) belonging to the pentatricopeptide repeat proteins (PPRs) family play an essential role in plant growth and development including their binding to CMS-associated mitochondrial RNAs leading to fertility restoration. The present study identified 22 mitochondrial-specific PPRs in pigeonpea and explored the underlying mechanisms of restoration of fertility in the A4 CMS system through yeast-three hybrid studies. The identified gene was functionally validated through transgenic expression in Arabidopsis model system and obtained conclusive evidence that the identified Rf-PPR was responsible for fertility restoration. The sub-cellular localization studies implied that the identified Rf-PPR is mitochondrial targeting. The study demonstrated that due to the interaction between mitochondrial CMS mRNA and nuclear Rf-PPR protein, post-transcriptional modification occurred, leading to the inability to translate and accumulate cytotoxic CMS protein resulting in fertility restoration. The study specifically looks into the RNA-protein interaction occurring at the nucleo-cytoplasmic level in the A4 cytoplasm of Cajanus cajanifolius. HighlightsThe study identifies the restoration of fertility genes corresponding to the CMS-causing orf147 gene.