scholarly journals What Does the Molecular Genetics of Different Types of Restorer-of-Fertility Genes Imply?

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 361 ◽  
Author(s):  
Tomohiko Kubo ◽  
Takumi Arakawa ◽  
Yujiro Honma ◽  
Kazuyoshi Kitazaki
Keyword(s):  
Male Sterility ◽  
Rna Binding ◽  
Genetic Model ◽  
Mitochondrial Gene ◽  
Molecular Genetic ◽  
Protein A ◽  
Nuclear Gene ◽  
Hybrid Seed Production ◽  
Pentatricopeptide Repeat ◽  
Restorer Of Fertility

Cytoplasmic male sterility (CMS) is a widely used trait for hybrid seed production. Although male sterility is caused by S cytoplasm (male-sterility inducing mitochondria), the action of S cytoplasm is suppressed by restorer-of-fertility (Rf), a nuclear gene. Hence, the genetics of Rf has attained particular interest among plant breeders. The genetic model posits Rf diversity in which an Rf specifically suppresses the cognate S cytoplasm. Molecular analysis of Rf loci in plants has identified various genes; however, pentatricopeptide repeat (PPR) protein (a specific type of RNA-binding protein) is so prominent as the Rf-gene product that Rfs have been categorized into two classes, PPR and non-PPR. In contrast, several shared features between PPR- and some non-PPR Rfs are apparent, suggesting the possibility of another grouping. Our present focus is to group Rfs by molecular genetic classes other than the presence of PPRs. We propose three categories that define partially overlapping groups of Rfs: association with post-transcriptional regulation of mitochondrial gene expression, resistance gene-like copy number variation at the locus, and lack of a direct link to S-orf (a mitochondrial ORF associated with CMS). These groups appear to reflect their own evolutionary background and their mechanism of conferring S cytoplasm specificity.

scholarly journals Pentatricopeptide-repeat family protein RF6 functions with hexokinase 6 to rescue rice cytoplasmic male sterility

2015 ◽  
Vol 112 (48) ◽  
pp. 14984-14989 ◽  
Author(s):  
Wenchao Huang ◽  
Changchun Yu ◽  
Jun Hu ◽  
Lili Wang ◽  
Zhiwu Dan ◽  
...  
Keyword(s):  
Cytoplasmic Male Sterility ◽  
Male Sterility ◽  
Pollen Sterility ◽  
Mitochondrial Rna ◽  
Hybrid Seed Production ◽  
Pentatricopeptide Repeat ◽  
Transcript Accumulation ◽  
Aberrant Transcript ◽  
Family Protein ◽  
Restorer Of Fertility

Cytoplasmic male sterility (CMS) has been extensively used for hybrid seed production in many major crops. Honglian CMS (HL-CMS) is one of the three major types of CMS in rice and has contributed greatly to food security worldwide. The HL-CMS trait is associated with an aberrant chimeric mitochondrial transcript, atp6-orfH79, which causes pollen sterility and can be rescued by two nonallelic restorer-of-fertility (Rf) genes, Rf5 or Rf6. Here, we report the identification of Rf6, which encodes a novel pentatricopeptide repeat (PPR) family protein with a characteristic duplication of PPR motifs 3–5. RF6 is targeted to mitochondria, where it physically associates with hexokinase 6 (OsHXK6) and promotes the processing of the aberrant CMS-associated transcript atp6-orfH79 at nucleotide 1238, which ensures normal pollen development and restores fertility. The duplicated motif 3 of RF6 is essential for RF6-OsHXK6 interactions, processing of the aberrant transcript, and restoration of fertility. Furthermore, reductions in the level of OsHXK6 result in atp6-orfH79 transcript accumulation and male sterility. Together these results reveal a novel mechanism for CMS restoration by which RF6 functions with OsHXK6 to restore HL-CMS fertility. The present study also provides insight into the function of hexokinase 6 in regulating mitochondrial RNA metabolism and may facilitate further exploitation of heterosis in rice.

scholarly journals The molecular basis for allelic differences suggests Restorer-of-fertility 1 is a complex locus in sugar beet (Beta vulgaris L.)

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Takumi Arakawa ◽  
Muneyuki Matsunaga ◽  
Katsunori Matsui ◽  
Kanna Itoh ◽  
Yosuke Kuroda ◽  
...  
Keyword(s):  
Sugar Beet ◽  
Molecular Basis ◽  
Fertility Restoration ◽  
Mitochondrial Protein ◽  
Nuclear Gene ◽  
Pcr Primers ◽  
Hybrid Seed Production ◽  
Dominant Allele ◽  
Restorer Of Fertility ◽  
Complex Locus

Abstract Background Cytoplasmic male sterility (CMS) is a widely used trait for hybrid seed production in many crops. Sugar beet CMS is associated with a unique mitochondrial protein named preSATP6 that forms a 250-kDa complex. Restorer-of-fertility 1 (Rf1) is a nuclear gene that suppresses CMS and is, hence, one of the targets of sugar beet breeding. Rf1 has dominant, semi-dominant and recessive alleles, suggesting that it may be a multi-allelic locus; however, the molecular basis for differences in genetic action is obscure. Molecular cloning of Rf1 revealed a gene (orf20) whose protein products produced in transgenics can bind with preSATP6 to generate a novel 200-kDa complex. The complex is also detected in fertility-restored anthers concomitant with a decrease in the amount of the 250-kDa complex. Molecular diversity of the Rf1 locus involves organizational diversity of a gene cluster composed of orf20-like genes (RF-Oma1s). We examined the possibility that members of the clustered RF-Oma1 in this locus could be associated with fertility restoration. Results Six yet uncharacterized RF-Oma1s from dominant and recessive alleles were examined to determine whether they could generate the 200-kDa complex. Analyses of transgenic calli revealed that three RF-Oma1s from a dominant allele could generate the 200-kDa complex, suggesting that clustered RF-Oma1s in the dominant allele can participate in fertility restoration. None of the three copies from two recessive alleles was 200-kDa generative. The absence of this ability was confirmed by analyzing mitochondrial complexes in anthers of plants having these recessive alleles. Together with our previous data, we designed a set of PCR primers specific to the 200-kDa generative RF-Oma1s. The amount of mRNA measured by this primer set inversely correlated with the amount of the 250-kDa complex in anthers and positively correlated with the strength of the Rf1 alleles. Conclusions Fertility restoration by sugar beet Rf1 can involve multiple RF-Oma1s clustered in the locus, implying that stacking 200-kDa generative copies in the locus strengthens the efficacy, whereas the absence of 200-kDa generative copies in the locus makes the allele recessive irrespective of the copy number. We propose that sugar beet Rf1 is a complex locus.

scholarly journals Localization of the Rf3 restorer-of-fertility gene for maize S-type cytoplasmic male sterility

2012 ◽  
Author(s):  
◽  
Tiffany Langewisch
Keyword(s):  
Cytoplasmic Male Sterility ◽  
Candidate Gene ◽  
Male Sterility ◽  
Pollen Grains ◽  
Candidate Gene Approach ◽  
Chromosome 2 ◽  
Pentatricopeptide Repeat ◽  
Restorer Of Fertility ◽  
Ppr Proteins ◽  
Pentatricopeptide Repeat Proteins

Maize S-type cytoplasmic male sterility (CMS-S) is a maternally inherited trait that prevents pollen grains from developing to maturity. CMS-S is associated with the high levels of a novel mitochondrial transcript, orf355/orf77. Cleavage of this RNA, mediated by the nuclear restorer Rf3, reverses the sterility. Rf3 was previously mapped on the long arm of chromosome 2. The goals of this research were to fine-map the locus and to identify Rf3 using a candidate gene approach. Genotyping of nearisogenic lines (NILs) mapped Rf3 to a 1.98 Mb region of 2L. Six candidate genes, all predicted to code for mitochondrially targeted pentatricopeptide repeat proteins (PPR), were PCR-amplified, sequenced, and compared from multiple Rf3-containing NILs and non-restoring rf3 inbreds. One PPR-Rf3 candidate gene had two consistent differences between multiple restoring and non-restoring lines. Gene expression in pre-emergent tassels from the fertility-restored and non-restored plants was compared. Within the 3 Mb region surrounding Rf3, 9 genes were differentially expressed between restoring and non-restoring lines, including genes that could code for an ATP-binding protein, an ATPase, and four PPR proteins. Although Rf3 has not yet been identified, this study has revealed five promising candidates.

Selection of Nuclear Genotypes Associated with the Thermo-inducibility of Owen-type Cytoplasmic Male Sterility in Sugar Beet (Beta vulgaris L.)

2021 ◽  
Author(s):  
Hiroaki Matsuhira ◽  
Kazuyoshi Kitazaki ◽  
Katsunori Matsui ◽  
Keisi Kubota ◽  
Yosuke Kuroda ◽  
...  
Keyword(s):  
Sugar Beet ◽  
Cytoplasmic Male Sterility ◽  
Male Sterility ◽  
Beta Vulgaris ◽  
Parental Line ◽  
Hybrid Seed Production ◽  
Male Sterile ◽  
Flowering Season ◽  
Restorer Of Fertility ◽  
The Stability

Abstract The stability of cytoplasmic male sterility expression in several genetic backgrounds was investigated in sugar beet (Beta vulgaris L.). Nine genetically heterogenous plants from old cultivars were crossed with a cytoplasmic male-sterile line to obtain 266 F1 plants. Based on marker analysis using a multiallelic DNA marker linked to restorer-of-fertility 1 (Rf1), we divided the F1 plants into 15 genotypes. We evaluated the phenotypes of the F1 plants under two environmental conditions: greenhouse rooms with or without daytime heating during the flowering season. Three phenotypic groups appeared: those consistently expressing male sterility (MS), those consistently having restored pollen fertility, and those expressing MS in a thermo-sensitive manner. All plants in the consistently male-sterile group inherited a specific Rf1 marker type named p4. We tested the potential for thermo-induced male-sterile plants to serve as seed parents for hybrid seed production, and three genotypes were selected. Open pollination by a pollen parental line with a dominant trait of red-pigmented hypocotyls and leaf veins resulted in seed setting on thermo-induced male-sterile plants, indicating that their female organs were functional. More than 99.9% of the progeny expressed the red pigmentation trait; hence, highly pure hybrids were obtained. We determined the nucleotide sequences of Rf1 from the three genotypes: one had a novel allele and two had known alleles, of which one was reported to have been selected previously as a nonrestoring allele at a single US breeding station but not at other stations in the US, or in Europe or Japan, suggesting environmental sensitivity.

scholarly journals Identification of Rf9, a Gene Contributing to the Genetic Complexity of Fertility Restoration in Hybrid Wheat

2020 ◽  
Vol 11 ◽  
Author(s):  
Fahimeh Shahinnia ◽  
Manuel Geyer ◽  
Annette Block ◽  
Volker Mohler ◽  
Lorenz Hartl
Keyword(s):  
Fertility Restoration ◽  
Snp Markers ◽  
Genetic Maps ◽  
Hybrid Seed Production ◽  
Hybrid Wheat ◽  
Pentatricopeptide Repeat ◽  
Male Sterile ◽  
Transcription Termination Factor ◽  
Restorer Of Fertility ◽  
Genes Encoding

Wheat (Triticum aestivum L.) is a self-pollinating crop whose hybrids offer the potential to provide a major boost in yield. Male sterility induced by the cytoplasm of Triticum timopheevii is a powerful method for hybrid seed production. Hybrids produced by this method are often partially sterile, and full fertility restoration is crucial for wheat production using hybrid cultivars. To identify the genetic loci controlling fertility restoration in wheat, we produced two cytoplasmic male-sterile (CMS) backcross (BC1) mapping populations. The restorer lines Gerek 79 and 71R1203 were used to pollinate the male-sterile winter wheat line CMS-Sperber. Seed set and numbers of sterile spikelets per spike were evaluated in 340 and 206 individuals of the populations derived from Gerek 79 and 71R1203, respectively. Genetic maps were constructed using 930 and 994 single nucleotide polymorphism (SNP) markers, spanning 2,160 and 2,328 cM over 21 linkage groups in the two populations, respectively. Twelve quantitative trait loci (QTL) controlled fertility restoration in both BC1 populations, including a novel restorer-of-fertility (Rf) locus flanked by the SNP markers IWB72413 and IWB1550 on chromosome 6AS. The locus was mapped as a qualitative trait in the BC1 Gerek 79 population and was designated Rf9. One hundred-nineteen putative candidate genes were predicted within the QTL region on chromosome 6AS. Among them were genes encoding mitochondrial transcription termination factor and pentatricopeptide repeat-containing proteins that are known to be associated with fertility restoration. This finding is a promising step to better understand the functions of genes for improving fertility restoration in hybrid wheat.

scholarly journals Genome-wide identification of the restorer-of-fertility-like (RFL) gene family in Brassica napus and expression analysis in Shaan2A cytoplasmic male sterility

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Luyun Ning ◽  
Hao Wang ◽  
Dianrong Li ◽  
Yonghong Li ◽  
Kang Chen ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Cytoplasmic Male Sterility ◽  
Gene Family ◽  
Male Sterility ◽  
Expression Analysis ◽  
Gene Clusters ◽  
Hybrid Breeding ◽  
Pentatricopeptide Repeat ◽  
Specific Expression ◽  
Restorer Of Fertility

Abstract Background Cytoplasmic male sterility (CMS) is very important in hybrid breeding. The restorer-of-fertility (Rf) nuclear genes rescue the sterile phenotype. Most of the Rf genes encode pentatricopeptide repeat (PPR) proteins. Results We investigated the restorer-of-fertility-like (RFL) gene family in Brassica napus. A total of 53 BnRFL genes were identified. While most of the BnRFL genes were distributed on 10 of the 19 chromosomes, gene clusters were identified on chromosomes A9 and C8. The number of PPR motifs in the BnRFL proteins varied from 2 to 19, and the majority of BnRFL proteins harbored more than 10 PPR motifs. An interaction network analysis was performed to predict the interacting partners of RFL proteins. Tissue-specific expression and RNA-seq analyses between the restorer line KC01 and the sterile line Shaan2A indicated that BnRFL1, BnRFL5, BnRFL6, BnRFL8, BnRFL11, BnRFL13 and BnRFL42 located in gene clusters on chromosomes A9 and C8 were highly expressed in KC01. Conclusions In the present study, identification and gene expression analysis of RFL gene family in the CMS system were conducted, and seven BnRFL genes were identified as candidates for the restorer genes in Shaan2A CMS. Taken together, this method might provide new insight into the study of Rf genes in other CMS systems.

scholarly journals Characterization and transcriptome analysis of a dominant genic male sterile cotton mutant

2020 ◽  
Author(s):  
Xinqi Cheng ◽  
Xinyu Zhang ◽  
Fei Xue ◽  
Shouhong Zhu ◽  
Yanjun Li ◽  
...  
Keyword(s):  
Male Sterility ◽  
Transcriptome Analysis ◽  
Nuclear Gene ◽  
Pollen Grains ◽  
Anther Development ◽  
Hybrid Seed Production ◽  
Cytological Observation ◽  
Male Sterile ◽  
Tetrad Stage ◽  
Go Terms

Abstract Background : Male sterility is an efficient trait for hybrid seed production and germplasm innovation. Until now, most studies on male sterility were on cytoplasmic and recessive genic sterility, with few on dominant genic male sterility, especially in cotton, due to lack of such mutant.Results : We discovered a natural male sterile (MS) Sea Island cotton ( G. barbadense ) mutant, Genetic analysis showed the mutation was caused by a dominant mutation in a single nuclear gene. Comparative cytological observation of anther sections from MS and WT uncovered cellular differences in anther at and after the tetrad stage of pollen mother cells (PMC). In the MS anthers, the outer wall of pollen grains was free of spinules, the tapetum was vacuolated and showed delayed degradation, consequently, no functional pollen grains. Comparison of transcriptomes from meiosis, tetrad, mononuclear and binuclear pollen, and pollen maturation stages identified 13,783 non-redundant differentially expressed genes (DEGs) between MS and WT. Based on the number of DEGs, analyses of enriched GO terms and KEGG pathways, it was evident that significant transcriptomic changes occurred at and after the tetrad stage, consistent with cytological observation, and that the major differences were on metabolism of starch, sucrose, ascorbate, aldarate, alanine, aspartate and glutamate, and biosynthesis of cutin, suberine and wax. WGCNA analysis identified five modules containing 920 genes highly related to anther development, especially the greenyellow module with 54 genes that was highly associated with PMC meiosis and tetrad formation. A NAC transcription factor ( Gh_D11G2469 ) was identified as a hub gene for this module, which warrants further functional characterization.Conclusions : We demonstrated that the MS trait was controlled by a single dominant nuclear gene and caused by delayed tapetum degradation at the tetrad stage. Comparative transcriptome analysis and gene network construction identified DEGs, enriched GO terms and metabolic pathways, and hub genes potentially associated with anther development and the MS trait, which will contribute to important ideas and basis of the experimental data related to the molecular mechanism of DGMS and the innovation of cotton germplasm resources.

scholarly journals Molecular-Genetic Characterization of CMS-S Restorer-of-Fertility Alleles Identified in Mexican Maize and Teosinte

Genetics ◽  
2004 ◽  
Vol 166 (2) ◽  
pp. 959-970
Author(s):  
Susan Gabay-Laughnan ◽  
Christine D Chase ◽  
Victor M Ortega ◽  
Liming Zhao
Keyword(s):  
Mitochondrial Gene ◽  
Molecular Genetic ◽  
Chromosome 2 ◽  
Restorer Of Fertility ◽  
Processing Event ◽  
Mitochondrial Transcripts ◽  
Internal Processing ◽  
Molecular Genetic Characterization ◽  
Mexican Maize

Abstract Restorer-of-fertility (Rf) alleles for S-type cytoplasmic male sterility (CMS-S) are prevalent in Mexican races of maize and teosinte. Forty-five Rf alleles from 26 races of maize and 6 Rf alleles from different accessions of teosinte were found to be homozygous viable, consistent with the hypothesis that they are naturally occurring Rf alleles. Mapping and allelism studies were performed to assess the number of genes represented by these 51 alleles. Forty-two of the Rf alleles mapped to the long arm of chromosome 2 (2L), and 5 of these were further mapped to the whp1-rf3 region. The Rf3 restoring allele, found in some U.S. maize inbred lines, cosegregates with internal processing of CMS-S mitochondrial transcripts. Three of the 5 mapped Rf alleles were associated with a similar RNA processing event. Allelism or tight linkage was confirmed between Rf3 and 2 teosinte alleles (Rf K-69-6 and Rf 9477) and between Rf3 and the Cónico Norteño allele Rf C-N (GTO 22). The rf3 region of 2L potentially encodes a complex of linked rf genes. The prevalence of restoring alleles in this chromosomal region, among normal-cytoplasm accessions of Mexican maize and teosinte, supports the conclusion that these alleles have functions in normal mitochondrial gene expression that by chance allow them to restore male fertility in S cytoplasm.

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