RNA editing in CMS wheat: Influence of nuclear background leads to differential editing on orf 256

Abstract

RNA editing and cytoplasmic male sterility are two important and correlated phenomenons in mitochondria of higher plants. We investigated the occurrence of RNA editing in orf 256, which is implicated in causing male sterility in wheat in two different CMS lines carrying different cytoplasms along with their fertility restored lines. This study provides the first preliminary report of RNA editing in orf 256 with greater frequency observed in a fertility-restored line compared to male sterile line carrying the T.timopheevi cytoplasm. In order to investigate whether a similar process occurs in a line carrying the T.araraticum cytoplasm, it was observed that the male sterile line showed a complete lack of editing in orf 256 whereas in the restored hybrids there was an increase in frequency of editing. Editing sites were also found conserved in both the hybrids at 381 position of C residue indicating the non random nature of editing especially under different nuclear backgrounds. Thus RNA editing might be involved in either causing male sterility or restoration of fertility in these two systems suggesting that a common mechanism may exist in these two different cytoplasms.