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 ◽  
...  

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.

2012 ◽  
Author(s):  
◽  
Tiffany Langewisch

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.


2021 ◽  
Author(s):  
Hiroaki Matsuhira ◽  
Kazuyoshi Kitazaki ◽  
Katsunori Matsui ◽  
Keisi Kubota ◽  
Yosuke Kuroda ◽  
...  

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.


BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Luyun Ning ◽  
Hao Wang ◽  
Dianrong Li ◽  
Yonghong Li ◽  
Kang Chen ◽  
...  

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.


Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 361 ◽  
Author(s):  
Tomohiko Kubo ◽  
Takumi Arakawa ◽  
Yujiro Honma ◽  
Kazuyoshi Kitazaki

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.


2019 ◽  
Vol 20 (22) ◽  
pp. 5530
Author(s):  
Bingbing Zhang ◽  
Xuexian Zhang ◽  
Meng Zhang ◽  
Liping Guo ◽  
Tingxiang Qi ◽  
...  

The cytoplasmic male sterility (CMS)/restorer-of-fertility system is an important tool to exploit heterosis during commercially hybrid seed production. The importance of long noncoding RNAs (lncRNAs) in plant development is recognized, but few analyses of lncRNAs during anther development of three-line hybrid cotton (CMS-D2 line A, maintainer line B, restorer-of-fertility line R) have been reported. Here, we performed transcriptome sequencing during anther development in three-line hybrid cotton. A total of 80,695 lncRNAs were identified, in which 43,347 and 44,739 lncRNAs were differentially expressed in A–B and A–R comparisons, respectively. These lncRNAs represent functional candidates involved in CMS and fertility restoration. GO analysis indicated that cellular hormone metabolic processes and oxidation–reduction reaction processes might be involved in CMS, and cellular component morphogenesis and small molecular biosynthetic processes might participate in fertility restoration. Additionally, 63 lncRNAs were identified as putative precursors of 35 miRNAs, and quantitative reverse transcription polymerase chain reaction (qRT-PCR) showed a similar expression pattern to RNA-seq data. Furthermore, construction of lncRNA regulatory networks indicated that several miRNA–lncRNA–mRNA networks might be involved in CMS and fertility restoration. Our findings provide systematic identification of lncRNAs during anther development and lays a solid foundation for the regulatory mechanisms and utilization in hybrid cotton breeding.


2019 ◽  
Author(s):  
Bingbing Zhang ◽  
Xuexian Zhang ◽  
Meng Zhang ◽  
Liping Guo ◽  
Tingxiang Qi ◽  
...  

Abstract Background Hybrid cotton has greatly contributed to global increase in cotton productivity. The cytoplasmic male sterility (CMS)/restorer-of-fertility system is an important tool to exploit heterosis because it is convenient for commercial hybrid seed production. The importance of long noncoding RNAs (lncRNAs) in plant development is recognized, few analyses of lncRNAs during anther development of three-line hybrid cotton (CMS-D2 line A, maintainer line B, restorer-of-fertility line R) have been reported. Results Here, we performed transcriptome sequencing during anther development in Upland cotton carrying cytoplasmic male sterile Gossypium harknessii (D2) cytoplasm. Totally 80,695 lncRNAs were identified, in which 43,347 and 44,739 lncRNAs were differentially expressed in A–B and A–R comparisons, respectively. These lncRNAs represent functional candidates involved in CMS and fertility restoration. Gene ontology enrichment analysis indicated that cellular hormone metabolic processes and oxidation–reduction reaction processes might be involved in CMS, and cellular component morphogenesis and small molecular biosynthetic processes might participate in fertility restoration. Analysis of the putative relationship between lncRNAs and miRNAs revealed that 63 lncRNAs were identified as putative precursors of 35 miRNAs, and qRT-PCR analysis showed a similar expression pattern to that of RNA-sequencing data. Furthermore, construction of lncRNA regulatory networks indicated that several miRNA–lncRNA–mRNA networks might be involved in CMS and fertility restoration. Conclusion Our findings provide systematic identification of lncRNAs during anther development and lays a solid foundation for future investigation of the regulatory molecular mechanisms and utilization in ­­breeding of hybrid cotton.


2019 ◽  
Vol 20 (3) ◽  
pp. 578 ◽  
Author(s):  
Peng Wang ◽  
Qiaohua Lu ◽  
Yixin Ai ◽  
Yihao Wang ◽  
Tiantian Li ◽  
...  

Cytoplasmic male sterility (CMS), which is controlled by mitochondrial genes, is an important trait for commercial hybrid seed production. So far, genes controlling this trait are still not clear in pepper. In this study, complete mitochondrial genomes were sequenced and assembled for the CMS line 138A and its maintainer line 138B. The genome size of 138A is 504,210 bp, which is 8618 bp shorter than that of 138B. Meanwhile, more than 214 and 215 open reading frames longer than 100 amino acids (aas) were identified in 138A and 138B, respectively. Mitochondrial genome structure of 138A was quite different from that of 138B, indicating the existence of recombination and rearrangement events. Based on the mitochondrial genome sequence and structure variations, mitochondrion of 138A and FS4401, a Korean origin CMS line, may have inherited from a common female ancestor, but their CMS traits did originate separately. Candidate gene selection was performed according to the published characteristics of the CMS genes, including the presence SNPs and InDels, located in unique regions, their chimeric structure, co-transcription, and transmembrane domain. A total of 35 ORFs were considered as potential candidate genes and 14 of these were selected, with orf300a and 0rf314a as strong candidates. A new marker, orf300a, was developed which did co-segregate with the CMS trait.


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