Researchers from Tohoku University and partners successfully restored pollen development in sterile rice by disrupting a mitochondrial gene using mitochondrion-targeted transcription activator-like effector nucleases (mitoTALENs). The results are published in BioRxiv.

Genomes in plant mitochondria sometimes contain cytoplasmic male sterility (CMS)-associated genes, which are used by breeders to develop high-yielding F1 hybrid seed in different crops. The gene orf352 was found to be associated with CMS in rice, however, its role remains elusive. Thus, the research team used mitoTALENs to turn off orf352 in the mitochondrial genome of cytoplasmic male sterile rice RT102A.

A total of 18 independent transformation events in RT102A were isolated, which indicated genome editing of orf352 including total deletion of the gene in the mitochondrial genome in several plants. Plants with a new mitochondrial gene encoding amino acids 179 to 352 of ORF352 showed similar shrunken pollen grain characteristic as RT102A, while the plants either lacking orf352 or harboring a new gene encoding amino acids 211 to 352 of ORF352 exhibited partial rescue of pollen viability and germination.

The findings of the study imply that orf352 disruption can partially restore pollen development, indicating that amino acids 179 to 210 from ORF352 may contribute to pollen abortion.

See https://www.isaaa.org/kc/cropbiotechupdate/article/default.asp?ID=18686