Transgenic expression of an unedited mitochondrial orfB gene product from wild abortive (WA) cytoplasm of rice (Oryza sativa L.) generates male sterility in fertile rice lines

Abstract

Over-expression of the unedited mitochondrial orfB gene product generates male sterility in fertile indica rice lines in a dose-dependent manner. Cytoplasmic male sterility (CMS) and nuclear-controlled fertility restoration are widespread developmental features in plant reproductive systems. In self-pollinated crop plants, these processes often provide useful tools to exploit hybrid vigour. The wild abortive CMS has been employed in the majority of the "three-line" hybrid rice production since 1970s. In the present study, we provide experimental evidence for a positive functional relationship between the 1.1-kb unedited orfB gene transcript, and its translated product in the mitochondria with male sterility. The generation of the 1.1-kb unedited orfB gene transcripts increased during flowering, resulting in low ATP synthase activity in sterile plants. Following insertion of the unedited orfB gene into the genome of male-fertile plants, the plants became male sterile in a dose-dependent manner with concomitant reduction of ATPase activity of F1F0-ATP synthase (complex V). Fertility of the transgenic lines and normal activity of ATP synthase were restored by down-regulation of the unedited orfB gene expression through RNAi-mediated silencing. The genetic elements deciphered in this study could further be tested for their use in hybrid rice development.

A genome-wide identification and analysis of the DYW-deaminase genes in the pentatricopeptide repeat gene family in cotton (Gossypium spp.)

“…For example, Wei et al (2008) found that the editing of atp9 change an arginine codon into a termination codon, shorting the protein to the standard in Ying xiang B while in Ying xiang A, which has no termination codon, cannot be a normal protein [34]. Wang et al (2009) found that RNA editing occurrence rates in atp6 and cox2 generally increase in sterile lines [35]; Chakraborty et al (2015) indicated that an over-expression of the unedited mitochondrial orfB gene generated male sterility in fertile rice lines in a dose-dependent manner, in which the unedited orfB gene expression increased, resulting in a low level of ATP synthase activity of F1F0-ATP synthase (complex V) [36]. In cotton, Suzuki et al (2013) identified RNA editing sites in eight mitochondrial genes among CMS-D8 three line systems, and found that the restorer gene may change RNA editing efficiency [37].…”

The key genes and pathways related to male sterility of eggplant revealed by comparative transcriptome analysis

“…A number of genes involved in MS have been defined and the network has been acknowledged as complicated [ 29 – 31 ]. With the increasing popularity of eggplant all over the world, the utilization of MS lines in eggplant breeding is more and more important to produce hybrid seeds.…”

Non-coding RNA may be associated with cytoplasmic male sterility in Silene vulgaris

“…Additionally, post-transcriptional modification through RNA editing (Hammani and Giegé, 2014) of CMS mitochondrial transcripts can be involved in fertility restoration. The unedited orfB gene, for example, was found to underlie male sterility in the wild abortive (WA) cytoplasm of rice (Chakraborty et al , 2015). Furthermore, complex mitochondrial–nuclear interactions related to changes in amino acid sequence might be associated with CMS.…”