A fertility restorer gene, Rf4, widely used for hybrid rice breeding encodes a pentatricopeptide repeat protein

Abstract

BackgroundUncontrolled expression of a certain mitochondrial gene often causes cytoplasmic male sterility (CMS) in plants. This phenotype is prevented by the presence of a fertility restorer (Rf) gene in the nuclear genome. Such CMS/Rf systems have been successfully used for breedings of F1 hybrid cultivars. In rice, approximately 99% of F1 hybrid cultivars have been developed using a wild abortive type of CMS (WA-CMS) and its Rf genes. Recently, a newly identified mitochondrial gene, orf352, was reported as a WA-CMS-causing gene.FindingsWe cloned and functionally characterized Rf4, a major Rf gene for WA-CMS. We revealed that Rf4 encoded a pentatricopeptide repeat-containing protein and reduced the orf352-containing transcripts, thereby restoring pollen fertility.ConclusionsThrough a map-based cloning, we have independently identified an allele of a recently reported Rf4 gene and demonstrated that the fertility restoration is controlled sporophytically.Electronic supplementary materialThe online version of this article (doi:10.1186/s12284-014-0028-z) contains supplementary material, which is available to authorized users.

Fine mapping of Rf2, a major locus controlling pollen fertility restoration in sorghum A1 cytoplasm, encodes a PPR gene and its validation through expression analysis

“…The M35‐1, a restorer on 296A (296A × M35‐1), might possess a novel Rf locus as all the previously reported Rf loci (Rf1, Rf5 and Rf6 that restore fertility on A1 cytoplasm) linked markers did not show any linkage with fertility restoration in this population. This is similar to involvement of different genes in the fertility restoration of single WA‐CMS in rice (Kazama & Toriyama, ; Pranathi et al., ). Further studies are required to map this new Rf locus involved in the restoration of fertility on A1.…”

Frequency and fertility restoration efficiency of Rf3 and Rf4 genes in Indian rice

“…() identified a mitochondria‐encoded gene, WA352, which is responsible for expression of male sterility in WA CMS. The molecular mechanism of fertility restoration of WA cytoplasm was experimentally proved recently for the Rf4 gene (Kazama and Toriyama , Tang et al. ).…”

Mapping QTLs for Fertility Restoration of Different Cytoplasmic Male Sterility Types in Rice Using Two Oryza sativa ×O. rufipogon Backcross Inbred Line Populations

“…For ID-type CMS, qRf1.4 colocated with qRf5 reported by Shen et al [35]; qRf10.1 and qRf10.2 located to both sides of Rf-4 detected by Li et al [14], which is also involved in restoring fertility of WA-type CMS. Recently, the gene Rf4 , which restores WA-type CMS near the QTL qRf10.2 (Figure 1) and encodes a pentatricopeptide repeat-containing protein, has been cloned [23, 24]. Thus, it may be considered that these QTLs are consistently detected across different environments and genetic backgrounds.…”

“…To date, more than 17 Rf genes or loci that rescue different CMS types have been identified, distributed across all rice chromosomes apart from chromosome 9 (Gramene, http://www.gramene.org). Of these, seven Rf genes have been identified and functionally characterized: Rf1 ( Rf1a and Rf1b ) for BT-type CMS [20, 21], Rf2 for LD-type CMS [22], Rf4 for WA-type CMS [23, 24], Rf5 and Rf6 for HL-CMS [25, 26], and Rf17 for CW-CMS [27]. Molecular cloning and characterization of these Rf genes not only further described the cytoplasmic-nuclear interactions, but also provided powerful molecular tools to assist in hybrid breeding by accelerating the development of novel restorer lines.…”