Fertility Restorer Gene Research Articles

Analysis of metabolic pathways related to fertility restoration and identification of fertility candidate genes associated with Aegilops kotschyi cytoplasm in wheat (Triticum aestivum L.)

BackgroundThermo-sensitive male-sterility based on Aegilops kotschyi cytoplasm (K-TCMS) plays an important role in hybrid wheat breeding. This has important possible applications in two-line hybrid wheat breeding but the genetic basis and molecular regulation mechanism related to fertility restoration are poorly understood. In this study, comparative transcriptome profiling based on RNA sequencing was conducted for two near-isogenic lines comprising KTM3315R and its sterile counterpart KTM3315A, a total of six samples (3 repetitions per group), in order to identify fertility restoration genes and their metabolic pathways.ResultsIn total, 2642 significant differentially expressed genes (DEGs) were detected, among which 1238 were down-regulated and 1404 were up-regulated in fertile anthers. Functional annotation enrichment analysis identified important pathways related to fertility restoration, such as carbohydrate metabolism, phenylpropanoid metabolism and biosynthesis, as well as candidate genes encoding pectin methylesterase and flavanone 3-hydroxylase. Moreover, transcription factor analysis showed that a large number of DEGs were mainly involved with the WRKY, bHLH, and MYB transcription factor families. Determination of total soluble sugar and flavonoid contents demonstrated that important metabolic pathways and candidate genes are associated with fertility restoration. Twelve DEGs were selected and detected by quantitative reverse-transcribed PCR, and the results indicated that the transcriptome sequencing results were reliable.ConclusionsOur results indicate that identified DEGs were related to the fertility restoration and they proved to be crucial in Aegilops kotschyi cytoplasm. These findings also provide a basis for exploring the molecular regulation mechanism associated with wheat fertility restoration as well as screening and cloning related genes.

Map-Based Cloning, Phylogenetic, and Microsynteny Analyses of ZmMs20 Gene Regulating Male Fertility in Maize.

Genic male sterility (GMS) mutant is a useful germplasm resource for both theory research and production practice. The identification and characterization of GMS genes, and assessment of male-sterility stability of GMS mutant under different genetic backgrounds in Zea may (maize) have (1) deepened our understanding of the molecular mechanisms controlling anther and pollen development, and (2) enabled the development and efficient use of many biotechnology-based male-sterility (BMS) systems for hybrid breeding. Here, we reported a complete GMS mutant (ms20), which displays abnormal anther cuticle and pollen development. Its fertility restorer gene ZmMs20 was found to be a new allele of IPE1 encoding a glucose methanol choline (GMC) oxidoreductase involved in lipid metabolism in anther. Phylogenetic and microsynteny analyses showed that ZmMs20 was conserved among gramineous species, which provide clues for creating GMS materials in other crops. Additionally, among the 17 maize cloned GMS genes, ZmMs20 was found to be similar to the expression patterns of Ms7, Ms26, Ms6021, APV1, and IG1 genes, which will give some clues for deciphering their functional relationships in regulating male fertility. Finally, two functional markers of ZmMs20/ms20 were developed and tested for creating maize ms20 male-sterility lines in 353 genetic backgrounds, and then an artificial maintainer line of ms20 GMS mutation was created by using ZmMs20 gene, ms20 mutant, and BMS system. This work will promote our understanding of functional mechanisms of male fertility and facilitate molecular breeding of ms20 male-sterility lines for hybrid seed production in maize.

Linkage Mapping and Genome-Wide Association Studies of the Rf Gene Cluster in Sunflower (Helianthus annuus L.) and Their Distribution in World Sunflower Collections.

Commercial hybrid seed production in sunflower currently relies on a single cytoplasmic male sterility (CMS) source, PET1 and the major fertility restoration gene, Rf1, leaving the crop highly vulnerable to issues with genetic bottlenecks. Therefore, having multiple CMS/Rf systems is important for sustainable sunflower production. Here, we report the identification of a new fertility restoration gene, Rf7, which is tightly linked to a new downy mildew (DM) resistance gene, Pl34, in the USDA sunflower inbred line, RHA 428. The Rf7 gene was genetically mapped to an interval of 0.6 cM on the lower end of linkage group (LG) 13, while Pl34 was mapped 2.1 cM proximal to the Rf7. Both the genes are located in a cluster of Rf and Pl genes. To gain further insights into the distribution of Rf genes in the sunflower breeding lines, we used a genome-wide association study (GWAS) approach to identify markers associated with the fertility restoration trait in a panel of 333 sunflower lines genotyped with 8,723 single nucleotide polymorphism (SNP) markers. Twenty-four SNP markers on the lower end of LG13 spanning a genomic region of 2.47 cM were significantly associated with the trait. The significant markers were surveyed in a world collection panel of 548 sunflower lines and validated to be associated with the Rf1 gene. The SNP haplotypes for the Rf1 gene are different from Rf5 and the Rf7gene located in the Rf gene cluster on LG13. The SNP and SSR markers tightly flanking the Rf7 gene and the Pl34 gene would benefit the sunflower breeders in facilitating marker assisted selection (MAS) of Rf and Pl genes.

Development and Validation of Markers for the Fertility Restorer Gene Rf1 in Sunflower.

Hybrid breeding in sunflowers based on CMS PET1 requires development of restorer lines carrying, in most cases, the restorer gene Rf1. Markers for marker-assisted selection have been developed, but there is still need for closer, more versatile, and co-dominant markers linked to Rf1. Homology searches against the reference sunflower genome using sequences of cloned markers, as well as Bacterial Artificial Chromosome (BAC)-end sequences of clones hybridizing to them, allowed the identification of two genomic regions of 30 and 3.9 Mb, respectively, as possible physical locations of the restorer gene Rf1 on linkage group 13. Nine potential candidate genes, encoding six pentatricopeptide repeat proteins, one tetratricopeptide-like helical domain, a probable aldehyde dehydrogenase 22A1, and a probable poly(A) polymerase 3 (PAPS3), were identified in these two genomic regions. Amplicon targeted next generation sequencing of these nine candidate genes for Rf1 was performed in an association panel consisting of 27 maintainer and 32 restorer lines and revealed the presence of 210 Single Nucleotide Polymorphisms (SNPs) and 67 Insertions/Deletions (INDELs). Association studies showed significant associations of 10 SNPs with fertility restoration (p-value < 10−4), narrowing Rf1 down to three candidate genes. Three new markers, one co-dominant marker 67N04_P and two dominant markers, PPR621.5R for restorer, and PPR621.5M for maintainer lines were developed and verified in the association panel of 59 sunflower lines. The versatility of the three newly developed markers, as well as of three existing markers for the restorer gene Rf1 (HRG01 and HRG02, Cleaved Amplified Polymorphic Sequence (CAPS)-marker H13), was analyzed in a large association panel consisting of 557 accessions.

Assessment of Genetic Variability and Identification of Fertility Restoration Genes Rf3, Rf4 of WA-CMS in RILs Population of Rice

<b>Assessment of Genetic Variability and Identification of Fertility Restoration Genes Rf3, Rf4 of WA-CMS in RILs Population of Rice</b>

Identifying the genes around Rf5 and Rf6 loci for the fertility restoration of WA-type cytoplasmic male sterile japonica rice (Oryza sativa) lines

Wild abortive (WA)-type, Honglian (HL)-type, and Chinsurah Boro II-type cytoplasm are three typical sterile cytoplasms used to generate three-line hybrid rice, and the fertility restorer (Rf) genes are considered to have specificity for fertility restoration of cytoplasmic male sterility (CMS) lines. ‘93-11’, an HL-type indica restorer line used widely in China, shows a weak ability to restore the fertility of WA-type CMS lines. Rf5 and Rf6, the fertility restorer genes for HL-type CMS, are members of a multigene cluster that encodes pentatricopeptide repeat proteins in ‘93-11’. In the present study, we studied the function of Rf genes around Rf5 and Rf6 loci on fertility restoration to WA-type CMS lines. We generated plants carrying WA-type cytoplasm and different genotypes at the Rf5 and Rf6 loci. All plants exhibited no seed setting on bagged panicles but had different anther and pollen grain morphologies. Plants with the genotypes of Rf5rf5rf6rf6, Rf5Rf5rf6rf6, rf5rf5Rf6rf6, rf5rf5Rf6Rf6, and Rf5rf5Rf6rf6 exhibited degraded anthers and typical abortive pollen grains, which were same as those of WA-NipA plants (rf5rf5rf6rf6); however, plants with the genotypes Rf5rf5Rf6Rf6, Rf5Rf5Rf6rf6, and Rf5Rf5Rf6Rf6 displayed restored anthers and pollen grains. These results indicated that Rf genes around the Rf5 and Rf6 loci had minor effects on the fertility restoration of WA-type CMS lines, which were mediated by dosage effects. Furthermore, these Rf genes functioned to decrease the WA352 (the mitochondrial gene conferring CMS-WA) transcript levels. Our findings will promote the development of three-line hybrids.

Unique fertility restoration suppressor genes for male-sterile CMS ANN2 and CMS ANN3 cytoplasms in sunflower (Helianthus annuus L.)

Single dominant fertility restoration (Rf) genes for cytoplasmic male-sterile (CMS) sunflower lines CMS ANN2 and CMS ANN3 were previously identified in three and five sources, respectively. However, expressions of the dominant Rf genes were suppressed when crossing restoration lines with three inbred lines. Preliminary results indicated that segregation of fertility in most testcross progeny families from crosses of half-diallel F1’s of restoration lines with the two CMS lines, respectively, did not agree with those of the F2 generation of the half-diallel crosses. In this study, using selected CMS ANN2 and CMS ANN3 plants without the silencing suppressor (S) genes, we confirmed the existence of S genes in the nuclear genomes of the CMS lines used for crossing of the two CMS cytoplasms. Inheritance study suggested that Rf gene suppression was controlled by a single dominant gene in specific backgrounds, whereas two to three complementary S genes could exist in certain backgrounds. Using testcross population Rf ANN2-P21/RHA 274//Rf ANN2-P21, a single S gene from RHA 274, designated S1, was mapped to a recombination suppressed region on the sunflower linkage group (LG) 3, co-segregating with 16 SSR or single nucleotide polymorphism (SNP) markers, flanked by NSA_003339 and ORS124 at a distance of 1.4 and 0.7 cM, respectively. These molecular markers will potentially assist in identifying lines without suppressor genes, including CMS lines. Unique suppression of Rf genes confirmed existence of suppressor (S1) gene in CMS lines that mapped to a recombination suppressed region on linkage group 3, which will enhance understanding of cytoplasm-nuclear interactions.

Association Mapping of Fertility Restorer Gene for CMS PET1 in Sunflower

The phenomenon of cytoplasmic male sterility (CMS), consisting in the inability to produce functional pollen due to mutations in mitochondrial genome, has been described in more than 150 plant species. With the discovery of nuclear fertility restorer (Rf) genes capable of suppressing the CMS phenotype, it became possible to use the CMS-Rf genetic systems as the basis for practical utilization of heterosis effect in various crops. Seed production of sunflower hybrids all over the world is based on the extensive use of the PET1 CMS combined with the Rf1 gene. At the same time, data on Rf1 localization, sequence, and molecular basis for the CMS PET1 type restoration of fertility remain unknown. Searching for candidate genes of the Rf1 gene has great fundamental and practical value. Therefore, in this study, association mapping of fertility restorer gene for CMS PET1 in sunflower was performed. The genome-wide association study (GWAS) results made it possible to isolate a segment 7.72 Mb in length on chromosome 13, in which 21 candidates for Rf1 fertility restorer gene were identified, including 20 pentatricopeptide repeat (PPR)family genes and one Probable aldehyde dehydrogenase gene. The results will serve as a basis for further study of the genetic nature and molecular mechanisms of pollen fertility restoration in sunflower, as well as for further intensification of sunflower breeding.

Marker assisted introgression of a major bacterial blight resistance gene, Xa38 into a rice maintainer line, APMS 6B

Bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae is a major production constraint for rice in India. We introgressed a major dominant BB resistance gene, Xa38 in the genetic background of APMS 6B, a maintainer line of APMS 6A (female parent of DRRH 3) through marker-assisted backcross breeding (MABB). The BB resistance gene, Xa38 was transferred to APMS 6B from the donor, PR 114 (Xa38) through two backcrosses. A single selected true BC2F1 plant having maximum recovery of recurrent parent genome and also high degree of BB resistance was selfed to generate BC2F2s. At BC2F2, plants homozygous for Xa38 were identified and were further confirmed for the absence of two major fertility restorer genes, Rf3 and Rf4. Eight best BC2F2 plants, homozygous positive for Xa38 and homozygous negative for Rf3 and Rf4 were selected and advanced up to BC2F6. At BC2F6, these introgression lines exhibited high degree of BB resistance against multiple Xoo strains and were similar to APMS 6B in respect to different agro-morphological traits.

Identification and Confirmation of New Molecular Markers Linked to The Fertility Restorer Genes in Sugar Beet

It is of special importance to track the fertility restoring alleles in plants such as sugar beet in which cytoplasmic male sterility (CMS) is used to produce hybrid seed, so that the possibility of detection of presence and absence of specific restoring alleles facilitates to a great extent the development of new O-type lines. For tagging of fertility restorer genes in sugar beet, an F2 population was used. At first, fertility scoring of F2 single plants in the field was done and the population was divided to four groups including fertile, half fertile, yellow sterile, and white sterile. Then, leaf sampling from the F2 single plants was accomplished for DNA extraction. Polymorphism of random primers of RAPD and STS primers was investigated in fertile and sterile bulks by bulk segregant analysis method. Several RAPD and STS primers produced polymorphism in fertile and sterile bulks. After testing the selected primers on the DNA of single plants of the bulk, F2 population and other sugar beet genotypes, one STS repulsion marker and one coupling marker were identified to distances of 17 and 8% recombination frequencies, respectively. In this research, the molecular basis of the genomic regions of fertility restoring loci of sugar beet was studied for the first time in Iran. These markers could be used for preliminary selection of O-type plants from pollinator populations and hence the time and costs related to pair crosses for identification of O-type character could be saved.

Homologous recombination changes the context of Cytochrome b transcription in the mitochondrial genome of Silene vulgaris KRA

BackgroundSilene vulgaris (bladder campion) is a gynodioecious species existing as two genders – male-sterile females and hermaphrodites. Cytoplasmic male sterility (CMS) is generally encoded by mitochondrial genes, which interact with nuclear fertility restorer genes. Mitochondrial genomes of this species vary in DNA sequence, gene order and gene content. Multiple CMS genes are expected to exist in S. vulgaris, but little is known about their molecular identity.ResultsWe assembled the complete mitochondrial genome from the haplotype KRA of S. vulgaris. It consists of five chromosomes, two of which recombine with each other. Two small non-recombining chromosomes exist in linear, supercoiled and relaxed circle forms. We compared the mitochondrial transcriptomes from females and hermaphrodites and confirmed the differentially expressed chimeric gene bobt as the strongest CMS candidate gene in S. vulgaris KRA. The chimeric gene bobt is co-transcribed with the Cytochrome b (cob) gene in some genomic configurations. The co-transcription of a CMS factor with an essential gene may constrain transcription inhibition as a mechanism for fertility restoration because of the need to maintain appropriate production of the necessary protein. Homologous recombination places the gene cob outside the control of bobt, which allows for the suppression of the CMS gene by the fertility restorer genes. We found the loss of three editing sites in the KRA mitochondrial genome and identified four sites with highly distinct editing rates between KRA and another S. vulgaris haplotypes (KOV). Three of these highly differentially edited sites were located in the transport membrane protein B (mttB) gene. They resulted in differences in MttB protein sequences between haplotypes.ConclusionsFrequent homologous recombination events that are widespread in plant mitochondrial genomes may change chromosomal configurations and also the control of gene transcription including CMS gene expression. Posttranscriptional processes, e.g. RNA editing shall be evaluated in evolutionary and co-evolutionary studies of mitochondrial genes, because they may change protein composition despite the sequence identity of the respective genes. The investigation of natural populations of wild species such as S. vulgaris are necessary to reveal important aspects of CMS missed in domesticated crops, the traditional focus of the CMS studies.

Progressive programmed cell death inwards across the anther wall in male sterile flowers of the gynodioecious plant Plantago lanceolata.

A cell death signal is perceived and responded to by epidermal cells first before being conveyed inwards across the anther wall in male sterile Plantago lanceolata flowers. In gynodioecious plants, floral phenotype is determined by an interplay between cytoplasmic male sterility (CMS)-promoting factors and fertility-restoring genes segregating in the nuclear background. Plantago lanceolata exhibits at least four different sterilizing cytoplasms. MS1, a "brown-anther" male sterile phenotype, segregates with a CMSI cytoplasm and a non-restoring nuclear background in P. lanceolata populations. The aim of this study was to investigate the cytology of early anther development in segregating hermaphrodite and male sterile flowers sharing the same CMSI cytoplasm, and to determine if the sterility phenotype correlates with any changes to the normal pattern of programmed cell death (PCD) that occurs during anther development. Cytology shows cellular abnormalities in all four anther wall layers (epidermis, endothecium, middle layer and tapetum), the persistence and enlargement of middle layer and tapetal cells, and the failure of microspore mother cells to complete meiosis in male sterile anthers. In these anthers, apoptotic-PCD occurs earlier than in fertile anthers and is detected in all four cell layers of the anther wall before the middle layer and tapetal cells become enlarged. PCD is separated spatially and temporally within the anther wall, occurring first in epidermal cells before extending radially to cells in the inner anther wall layers. This is the first evidence of a cell death signal being perceived and responded to by epidermal cells first before being conveyed inwards across the anther wall in male sterile plants.

Marker-assisted pyramiding of two major, broad-spectrum bacterial blight resistance genes, Xa21 and Xa33 into an elite maintainer line of rice, DRR17B.

Bacterial blight (BB) disease reduces the yield of rice varieties and hybrids considerably in many tropical rice growing countries like India. The present study highlights the development of durable BB resistance into the background of an elite maintainer of rice, DRR17B, by incorporating two major dominant genes, Xa21 and Xa33 through marker-assisted backcross breeding (MABB). Through two sets of backcrosses, the two BB resistance genes were transferred separately to DRR17B. In this process, at each stage of backcrossing, foreground selection was carried out for the target resistance genes and for non-fertility restorer alleles concerning the major fertility restorer genes Rf3 and Rf4, using gene-specific PCR-based markers, while background selection was done using a set of 61 and 64 parental polymorphic SSR markers respectively. Backcross derived lines possessing either Xa21 or Xa33 along with maximum genome recovery of DRR17B were identified at BC3F1 generation and selfed to develop BC3F2s. Plants harboring Xa21 or Xa33 in homozygous condition were identified among BC3F2s and were intercrossed with each other to combine both the genes. The intercross F1 plants (ICF1) were selfed and the intercross F2(ICF2) plants possessing both Xa21 and Xa33 in homozygous condition were identified with the help of markers. They were then advanced further by selfing until ICF4 generation. Selected ICF4 lines were evaluated for their resistance against BB with eight virulent isolates and for key agro-morphological traits. Six promising two-gene pyramiding lines of DRR17B with high level of BB resistance and agro-morphological attributes similar or superior to DRR17B with complete maintenance ability have been identified. These lines with elevated level of durable resistance may be handy tool for BB resistance breeding.

Genetic Characterization of the Fertility Restorer (Rf) Genes and Their Linked DNA Marker of the Male Sterile Eggplant Systems Having the Cytoplasm of the Wild Species

Genetic Characterization of the Fertility Restorer (Rf) Genes and Their Linked DNA Marker of the Male Sterile Eggplant Systems Having the Cytoplasm of the Wild Species

Improved versions of rice maintainer line, APMS 6B, possessing two resistance genes, Xa21 and Xa38, exhibit high level of resistance to bacterial blight disease

APMS 6B is the stable maintainer of the CMS line APMS 6A, which is the female parent of the popular Indian rice hybrid DRRH 3. APMS 6B has good combining ability and plant stature but is highly susceptible to bacterial blight (BB) disease. In order to improve the BB resistance of APMS 6B, we pyramided two major, dominant BB resistance genes, Xa21 and Xa38, through marker-assisted backcross breeding (MABB). Improved Samba Mahsuri (ISM) was used as the donor for Xa21 while PR 114 (Xa38) served as the donor for Xa38. Individual crosses [APMS 6B/ISM and APMS 6B/PR 114 (Xa38)] were performed, and true F1 plants were then backcrossed with APMS 6B and the MABB process was continued till BC3. A single positive BC3F1 plant identified from both the crosses with maximum genotypic and phenotypic similarity with APMS 6B was selfed to generate BC3F2s. At BC3F2 generation, plants homozygous for either Xa21 or Xa38 were identified and further confirmed for the absence of two major fertility restorer genes, Rf3 and Rf4. A single such homozygous BC3F2 plant, each from both the crosses, was then inter-mated to generate ICF1s (inter-cross F1s). Selected ICF1 plants possessing both the BB resistance genes were selfed to generate ICF2s. A total of 42 ICF2 plants homozygous for both Xa21 and Xa38 were identified and screened with parental polymorphic SSR markers to identify the best F2 plants having the maximum recurrent parent genome recovery. Twelve best ICF2 plants were advanced up to ICF5. The ICF5 lines displayed very high level of BB resistance and were similar to APMS 6B in terms of agro-morphological characters. Further, most of these lines also showed complete maintenance ability and such lines are being advanced for conversion to WA-CMS lines.

Genetics of fertility restoration in the isocytoplasm allonuclear C-group of cytoplasmic male sterility in maize

Maize is one of the first crops to produce hybrids using cytoplasmic male sterile lines. The C-type cytoplasmic male sterile (CMS-C) line is vital for hybrid seed production, and the fertility-restoration reaction along with its stability has a direct bearing on its applications. However, fertility restoration mechanism of CMS-C is complex and is still not clear so far. To further explore the factors affecting the fertility restoration of maize CMS, a series of test crosses were carried out by pollinating the isocytoplasm allonuclear CMS-C lines C48-2, Chuangzaosi and C478 with the test lines 18 bai, zi 330, 5022 and the restorer line A619, respectively. Four F2 populations and six double-cross combinations were obtained from the self-cross of fertility restored F1 and pollinating male-sterility-maintained F1 with the male-fertility-restored F1, respectively. Meanwhile, we developed the incomplete diallel-cross combinations using the isocytoplasm allonuclear male sterile lines as maternal parents and their respective maintainer lines 48-2, huangzaosi and 478 as paternal parents. All the F1, F2 and double-cross populations were planted at distinct locations in different years, and the fertility-restoration reaction was scored by field investigation and pollen staining with I2-IK. The results were as follows: 1) The same test line could restore the CMS-C line at a certain genetic background, but failed to restore the CMS-C line at the other genetic backgrounds, suggesting that the genetic background of CMS-C lines plays an important role in the fertility restoration. 2) The fertile-to-sterile segregation ratio of (C48-2×A619) F2 population planted in both Sichuan and Yunnan fited well to 15:1 by the χ 2 test. However, the fertility level of individuals in Yunnan mainly belonged to the 3 and 4grades, but which in Sichuan mainly belonged to the 5 grade, indicating the environmental factors had effect on the fertility-restoration reaction of (C48-2×A619) F2. 3) In our study, 18 bai could not restore C478, and 48-2 could not restore C478, but the fertile and sterile segregated plants were unexpectedly found in their double-cross population [(C478×18 bai) F1S×(C48-2×18 bai) F1F]. The similar case was also observed in the double-cross population [(C48-2 × zi 330) F1S × (C478 × zi 330) F1F]. Therefore, we speculated that there are minor fertility restorer genes not only in the nuclear background of C48-2 and C478, but also in zi 330 and 18 bai, and when these minor genes were gathered by hybridization, they could restore the fertility of C478 and C48-2. This conforms to the restorer genes dose-effect for fertility restoration in the plant CMS system. These results not only contribute to our understanding of the complexity and diversity of CMS-C restoration mechanism, but also provide an important reference for the practical applications about maize CMS-C.

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

AbstractSorghum is one of the pioneering cereal crops where cytoplasmic male sterility (CMS) was successfully exploited for mass production of F1 hybrid seed. Mapping genes for fertility restoration (Rf) is an important aspect of understanding the molecular basis of fertility restoration in crop plants. In this study, we fine‐mapped a fertility restoration locus, Rf2 of sorghum reported earlier (Jordan, Mace, Henzell, Klein, &amp; Klein, ), involving two F2 populations (296A × RS29 and 296A × DSV1) and newly developed SSR markers delimited Rf2 locus to 10.32‐kb region on chromosome 2. The Rf2 locus was tightly linked with two new SSRs, MS‐SB02‐3460 (0.14 cM) and MS‐SB02‐3466 (0.75 cM) on both sides, and hosted only one gene (Sobic.002G057050) of PPR gene family. Another new SSR marker developed in the study, MS‐SB02‐37912, forms the part of PPR gene and could act as a perfect marker in marker‐assisted breeding for fertility restoration involving Rf2 in sorghum breeding. The strong involvement of Sobic.002G057050 gene in fertility restoration was supported through RNA expression analysis.

Advance on Cytoplasmic Male Sterility and Fertility Restoration Genes in Maize

Advance on Cytoplasmic Male Sterility and Fertility Restoration Genes in Maize

Physical mapping and candidate gene prediction of fertility restorer gene of cytoplasmic male sterility in cotton

BackgroundCytoplasmic male sterility (CMS) is a maternally inherited trait failing to produce functional pollen. It plays a pivotal role in the exploitation of crop heterosis. The specific locus amplified fragment sequencing (SLAF-seq) as a high-resolution strategy for the identification of new SNPs on a large-scale is gradually applied for functional gene mining. The current study combined the bulked segregant analysis (BSA) with SLAF-seq to identify the candidate genes associated with fertility restorer gene (Rf) in CMS cotton.MethodsIllumina sequencing systematically investigated the parents. A segregating population comprising of 30 + 30 F2 individuals was developed using 3096A (female parent) as sterile and 866R (male parent) as a restorer. The original data obtained by dual-index sequencing were analyzed to obtain the reads of each sample that were compared to the reference genome in order to identify the SLAF tag with a polymorphism in parent lines and the SNP with read-associated coverage. Based on SLAF tags, SNP-index analysis, Euclidean distance (ED) correlation analysis, and whole genome resequencing, the hot regions were annotated.ResultsA total of 165,007 high-quality SLAF tags, with an average depth of 47.90× in the parents and 50.78× in F2 individuals, were sequenced. In addition, a total of 137,741 SNPs were detected: 113,311 and 98,861 SNPs in the male and female parent, respectively. A correlation analysis by SNP-index and ED initially located the candidate gene on 1.35 Mb of chrD05, and 20 candidate genes were identified. These genes were involved in genetic variations, single base mutations, insertions, and deletions. Moreover, 42 InDel markers of the whole genome resequencing were also detected.ConclusionsIn this study, associated markers identified by super-BSA could accelerate the study of CMS in cotton, and as well as in other crops. Some of the 20 genes’ preliminary characteristics provided useful information for further studies on CMS crops.

Screening for Fertility Restoration Genes linked Marker in Bacterial Blight Resistance Genes introgressed Segregating Population in rice

Screening for Fertility Restoration Genes linked Marker in Bacterial Blight Resistance Genes introgressed Segregating Population in rice