scholarly journals Molecular Tagging of the Ms Locus in Onion

2002 ◽  
Vol 127 (4) ◽  
pp. 576-582 ◽  
Author(s):  
Ali Fuat Gökçe ◽  
John McCallum ◽  
Yutaka Sato ◽  
Michael J. Havey
Keyword(s):  
Male Sterility ◽  
Fragment Length ◽  
Male Fertility ◽  
Fertility Restoration ◽  
Genomic Variation ◽  
Male Sterile ◽  
Single Nucleotide ◽  
Group I ◽  
Length Polymorphisms ◽  
Male Fertility Restoration

Cytoplasmic-genic male sterility (CMS) is used to produce hybrid onion (Allium cepa L.) seed. For the most widely used source of onion CMS, male sterility is conditioned by the interaction of the male-sterile (S) cytoplasm and the homozygous recessive genotype at a nuclear male-fertility restoration locus (Ms). Maintainer lines are used to seed propagate male-sterile lines, possess normal (N) male-fertile cytoplasm, and are homozyous recessive at the Ms locus. Due to the biennial nature of onion, it takes 4 to 8 years of crossing and scoring of progeny phenotypes to establish if maintainer lines can be extracted from an uncharacterized population or family. Identification of nuclear markers tightly linked to the Ms locus would allow for molecular-facilitated selection of maintainer lines. We evaluated testcross progenies from a segregating family for nuclear restoration of male fertility over at least three environments. Although segregations in the F2 family fit the expected 1:2:1 ratio (P = 0.973), the proportion of male-sterile testcross progenies showed significant (P < 0.01) year effects and it is therefore imperative to score male-fertility restoration over environments. Too many male-sterile testcross progenies were often observed, indicating that the dominant allele conditioning male-fertility restoration for S cytoplasm may not show complete penetrance. Segregations of amplified fragment length polymorphisms and restriction fragment length polymorphisms (RFLPs) revealed RFLPs flanking the Ms locus at 0.9 and 8.6 cM. An onion cDNA showing highly significant homology to the aldehyde dehydrogenase conditioned by the rf2 locus of maize was identified and mapped to linkage group I, independent of the Ms locus. A sample of commercial onion germplasm was evaluated for putative allelic diversity at the RFLP loci linked to Ms. The genomic region corresponding to the cDNA (AOB272) revealing the closest RFLP to Ms was sequenced to reveal numerous single nucleotide polymorphisms. Single-stranded conformational polymorphisms and single nucleotide extensions were developed that revealed genomic variation at AOB272-EcoRI. The use of these molecular markers to select maintainer lines in onion is discussed.

scholarly journals Linkage Equilibrium among Tightly Linked RFLPs and the Ms Locus in Open-pollinated Onion Populations

2002 ◽  
Vol 127 (6) ◽  
pp. 944-946 ◽  
Author(s):  
Ali Fuat Gökçe ◽  
Michael J. Havey
Keyword(s):  
Molecular Markers ◽  
Cytoplasmic Male Sterility ◽  
Fragment Length ◽  
Male Fertility ◽  
Fertility Restoration ◽  
Linkage Equilibrium ◽  
Male Sterile ◽  
Length Polymorphisms ◽  
Male Fertility Restoration ◽  
Restriction Fragment Length

Cytoplasmic male sterility (CMS) in onion (Allium cepa L.) is conditioned by the interaction of the male-sterile (S) cytoplasm with recessive alleles at a single nuclear male-fertility restoration locus (Ms). In order to seed propagate male-sterile plants (S msms), onion breeders must identify maintainer lines possessing normal (N) male-fertile cytoplasm and homozygous recessive at the Ms locus (N msms). Molecular markers have been identified distinguishing N and S cytoplasms and closely linked to the nuclear Ms locus. In this study, we evaluated testcross progenies from randomly selected N-cytoplasmic plants from three open-pollinated populations for nuclear restoration of male fertility over at least three environments. The Ms locus and linked restriction fragment length polymorphisms (0.9 and 1.7 cM) were at linkage equilibrium in all three open-pollinated onion populations, indicating that these linked markers cannot be used to identify maintaining genotypes in open-pollinated onion populations. However, cytoplasmic evaluations were effective in reducing the number of testcrosses required to identify CMS-maintaining genotypes.

scholarly journals The Dynamics of Gynodioecy in Plantago lanceolatu L. II. Mode of Action and Frequencies of Restorer Alleles

Genetics ◽  
1997 ◽  
Vol 147 (3) ◽  
pp. 1317-1328
Author(s):  
Anita A de Haan ◽  
Hans P Koelewijn ◽  
Maria P J Hundscheid ◽  
Jos M M Van Damme
Keyword(s):  
Cytoplasmic Male Sterility ◽  
Male Sterility ◽  
Allele Frequency ◽  
Mode Of Action ◽  
Male Fertility ◽  
Fertility Restoration ◽  
Plantago Lanceolata ◽  
Allele Frequencies ◽  
Male Sterile ◽  
Male Fertility Restoration

Male fertility in Plantago lanceolata is controlled by the interaction of cytoplasmic and nuclear genes. Different cytoplasmic male sterility (CMS) types can be either male sterile or hermaphrodite, depending on the presence of nuclear restorer alleles. In three CMS types of P. lanceolata (CMSI, CMSIIa, and CMSIIb) the number of loci involved in male fertility restoration was determined. In each CMS type, male fertility was restored by multiple genes with either dominant or recessive action and capable either of restoring male fertility independently or in interaction with each other (epistasis). Restorer allele frequencies for CMSI, CMSIIa and CMSIIb were determined by crossing hermaphrodites with “standard” male steriles. Segregation of male steriles vs. non-male steriles was used to estimate overall restorer allele frequency. The frequency of restorer alleles was different for the CMS types: restorer alleles for CMSI were less frequent than for CMSIIa and CMSIIb. On the basis of the frequencies of male steriles and the CMS types an “expected” restorer allele frequency could be calculated. The correlation between estimated and expected restorer allele frequency was significant.

scholarly journals Identification of Ms2, a Novel Locus Controlling Male-fertility Restoration of Cytoplasmic Male-sterility in Onion (Allium Cepa L.), and Development of Tightly Linked Molecular Markers

2021 ◽  
Author(s):  
Nari Yu ◽  
Sunggil Kim
Keyword(s):  
Cytoplasmic Male Sterility ◽  
Male Sterility ◽  
Allium Cepa ◽  
Male Fertility ◽  
Bulked Segregant Analysis ◽  
Fertility Restoration ◽  
Chromosome 2 ◽  
Rna Seq ◽  
Male Sterile ◽  
Male Fertility Restoration

Abstract Cytoplasmic male-sterility (CMS) has been exclusively used to produce F1 hybrid seeds of onion (Allium cepa L.). A single nuclear locus, Ms, is known to restore male-fertility of CMS in onions. Unstable male-sterile onions producing a small amount of pollen grains have been identified in a previous study. When such unstable male-sterile onions were crossed with stable male-sterile onions containing CMS-T cytoplasm, male-fertility was completely restored, although genotypes of the Ms locus were homozygous recessive. Inheritance patterns indicated that male-fertility restoration was controlled by a single locus designated as Ms2. A combined approach of bulked segregant analysis and RNA-seq was used to identify candidate genes for the Ms2 locus. High resolution melting (HRM) markers were developed based on single nucleotide polymorphisms (SNPs) detected by RNA-Seq. Comparative mapping of the Ms2 locus showed that Ms2 was positioned at the end of chromosome 2 with a distance of approximately 70 cM away from the Ms locus. Although 38 contigs containing reliable SNPs were analyzed using recombinants selected from 1,344 individuals, no contig showed perfect linkage to Ms2. Interestingly, transcription levels of orf725, a CMS-associated gene in onions, were significantly reduced in male-fertile individuals of segregating populations. However, no significant change in its transcription level was observed in individuals of a segregating population with male-fertility phenotypes determined by the Ms locus, suggesting that male-fertility restoration mechanism of Ms2 might be different from that of the Ms locus.

scholarly journals The Dominant Ms Allele in Onion Shows Reduced Penetrance

2010 ◽  
Vol 135 (1) ◽  
pp. 49-52 ◽  
Author(s):  
Sergio Melgar ◽  
Michael J. Havey
Keyword(s):  
Cytoplasmic Male Sterility ◽  
Male Sterility ◽  
Male Fertility ◽  
Fertility Restoration ◽  
The Other ◽  
Normal Male ◽  
Male Sterile ◽  
Mean Values ◽  
Reduced Penetrance ◽  
Male Fertility Restoration

The most commonly used source of cytoplasmic male sterility in onion (Allium cepa) is controlled by the interaction of the cytoplasm [male-sterile (S) or normal male-fertile (N)] and one nuclear male-fertility-restoration locus (Ms). Scoring of genotypes at Ms is generally done by testcrossing male-fertile to male-sterile (S msms) plants, followed by scoring of testcross progenies for male-fertility restoration. We identified two N-cytoplasmic families, one that was homozygous dominant and the other segregating at Ms. Plants from each of these two families were individually testcrossed to male-sterile onion. Nuclear restoration of male fertility in testcross progenies was evaluated in the field over 4 years. For male plants homozygous dominant at Ms, we expected testcross families to show 100% male-fertility restoration, but observed mean values between 46% and 100%. For plants segregating at Ms, we again observed lower than expected frequencies of male-fertility restoration. These results demonstrate that the dominant Ms allele shows reduced penetrance, requiring that male-fertility restoration be scored over years to more confidently assign genotypes at Ms.

scholarly journals Evaluation of AFLPs as Tags for the MS Locus in Onion

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 596c-596
Author(s):  
Yutaka Sato ◽  
Michael J. Havey
Keyword(s):  
Fragment Length ◽  
Male Fertility ◽  
Chromosome Region ◽  
Fertility Restoration ◽  
Male Sterile ◽  
Maintainer Line ◽  
Length Polymorphisms ◽  
Amplified Fragment Length Polymorphisms ◽  
Random Amplification ◽  
Onion Seed

The production of hybrid-onion seed depends on cytoplasmic male sterility (CMS) systems. The male-sterile line is seed propagated using a normal (N) cytoplasmic maintainer line homozygous recessive at the nuclear male-fertility restoration locus (MS). Because of onion's biennial generation time, 4 to 8 years are required to establish the genotype at the MS locus. The development of maintainer lines would benefit greatly from a genetic marker linked to the MS locus. Such a marker would allow breeders to establish the nuclear genotype in seedlings and flower only those plants that are maintainers (N msms) or plants that can be used to develop maintainers (N MSms), reducing the number of plants to be testcrossed or backcrossed to a sterile line. We evaluated restriction fragment length polymorphisms (RFLPs), random amplification of polymorphic DNA (RAPDs), and amplified fragment length polymorphisms (AFLPs) to tag the chromosome region carrying the MS locus. No RAPDs or RFLPs cosegregated with MS. AFLP markers were identified that phenotypically correlated with restoration of male fertility.

scholarly journals Variable Penetrance among Different Sources of the Male Fertility Restoration Allele of Onion

HortScience ◽  
2020 ◽  
Vol 55 (4) ◽  
pp. 543-546
Author(s):  
Hsiang-I Lee ◽  
Michael J. Havey
Keyword(s):  
Molecular Markers ◽  
Male Sterility ◽  
Male Fertility ◽  
Fertility Restoration ◽  
Male Sterile ◽  
Stainable Pollen ◽  
Breeding Lines ◽  
Reduced Penetrance ◽  
Different Sources ◽  
Male Fertility Restoration

Hybrid onion (Allium cepa) seed is produced using cytoplasmic male sterility (CMS). For the most commonly used source of onion CMS, male fertile plants possess male sterile (S) cytoplasm and dominant allele(s) at one nuclear male fertility locus (Ms). Because male fertility restoration is not necessary for bulb production, it is desirable to purge dominant alleles at Ms from populations and breeding lines to facilitate the development of male sterile inbreds for hybrid production. In this research, we used molecular markers to establish the cytoplasms and genotypes at Ms in progenies from testcrosses of male sterile lines with plants from three populations [B2354, Ailsa Craig (AC), and Sapporo-Ki (Ski)] possessing the dominant Ms allele. We scored male fertility of testcross progenies by visual examination of flowers and acetocarmine staining of pollen. Different sources of the dominant Ms allele showed significantly different amounts of male fertility restoration and proportions of stainable pollen, complicating visual selection against the dominant Ms allele. For AC and Ski, molecular markers correctly predicted male sterility vs. male fertility of progenies in the greenhouse and field. However, for B2354, male fertility restoration was less clear and especially difficult to score under field conditions, consistent with reduced penetrance of male fertility restoration for this source of the dominant Ms allele. These results will be of interest to onion breeders selecting S-cytoplasmic male sterile lines for hybrid onion development.

scholarly journals 069 Molecular-facilitated Selection of Maintainer Lines in Edible Onion (Allium cepa L.)

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 453B-453
Author(s):  
Ali Fuat Gokce ◽  
Michael J. Havey
Keyword(s):  
Molecular Markers ◽  
Male Sterility ◽  
Male Fertility ◽  
Fertility Restoration ◽  
Male Sterile ◽  
Nuclear Markers ◽  
Pcr Marker ◽  
Allium Cepa L ◽  
Male Fertility Restoration ◽  
Selection Of

Cytoplasmic-genic male sterility (CMS) is used to produce hybrid onion seed. For the most widely used source of CMS in onion, male sterility is conditioned by the interaction of sterile (S) cytoplasm and the homozygous recessive genotype at a single nuclear male-fertility restoration locus (Ms). Maintainer lines used to seed-propagate male-sterile lines possess normal fertile (N) cytoplasm and the homozyous recessive genotype at the Ms locus. Presently, it takes 4 to 8 years to establish if maintainer lines can be extracted from an uncharacterized population or family. We previously developed a PCR marker useful to distinguish N and S cytoplasms of onion. To tag the nuclear male-fertility restoration locus (Ms), we evaluated segregation at Ms over at least three environments. Segregations of AFLPs, RAPDs, and RFLPs revealed molecular markers flanking the Ms locus. We are working to convert these linked molecular markers to nonradioactive PCR-based detection. The organellar and nuclear markers were used to select plants from open-pollinated onion populations and determine if the number of test-crosses required to identify maintaining genotypes.

scholarly journals Seed Yield, Floral Morphology, and Lack of Male-fertility Restoration of Male-sterile Onion (Allium cepa) Populations Possessing the Cytoplasm of Allium galanthum

1999 ◽  
Vol 124 (6) ◽  
pp. 626-629 ◽  
Author(s):  
M.J. Havey
Keyword(s):  
Male Sterility ◽  
Allium Cepa ◽  
Seed Yield ◽  
Male Fertility ◽  
Fertility Restoration ◽  
Primary Source ◽  
Male Sterile ◽  
Calliphora Erythrocephala ◽  
Cytoplasmic Male Sterile ◽  
Male Fertility Restoration

The primary source (S cytoplasm) of cytoplasmic-genic male sterility (CMS) used to produce hybrid-onion (Allium cepa L.) seed traces back to a single plant identified in 1925 in Davis, California. Many open-pollinated populations also possess this cytoplasm, creating an undesirable state of cytoplasmic uniformity. Transfer of cytoplasms from related species into cultivated populations may produce new sources of CMS. In an attempt to diversify the cytoplasms conditioning male sterility, the cytoplasm of Allium galanthum Kar. et Kir. was backcrossed for seven generations to bulb-onion populations. The flowers of galanthum-cytoplasmic populations possess upwardly curved perianth and filaments with no anthers, making identification of male-sterile plants easier than for either S- or T-cytoplasmic male-sterile onion plants. Mean seed yield per bulb of the galanthum-cytoplasmic populations was measured in cages using blue-bottle flies (Calliphora erythrocephala Meig.) as pollinators and was not significantly different from one of two S-cytoplasmic male-sterile F1 lines, a T-cytoplasmic male-sterile inbred line, or N-cytoplasmic male-fertile lines. Male-sterile lines possessing either the S or galanthum cytoplasm were each crossed with populations known to be homozygous dominant and recessive at the nuclear locus conditioning male-fertility restoration of S cytoplasm and progenies were scored for male-fertility restoration. Nuclear restorers of male fertility for S cytoplasm did not condition male fertility for the galanthum-cytoplasmic populations. It is intended that these galanthum-cytoplasmic onion populations be used as an alternative male-sterile cytoplasm for the diversification of hybrid onion seed production.

scholarly journals Single Nucleotide Polymorphisms in Linkage Disequilibrium with the Male-fertility Restoration (Ms) Locus in Open-pollinated and Inbred Populations of Onion

2013 ◽  
Vol 138 (4) ◽  
pp. 306-309 ◽  
Author(s):  
Michael J. Havey
Keyword(s):  
Linkage Disequilibrium ◽  
Single Nucleotide Polymorphisms ◽  
Male Fertility ◽  
Fertility Restoration ◽  
Chromosome 2 ◽  
Nucleotide Polymorphisms ◽  
Male Sterile ◽  
Single Nucleotide ◽  
Inbred Populations ◽  
Male Fertility Restoration

Maintainer lines are used to seed propagate male-sterile lines for the development of hybrid onion (Allium cepa L.) cultivars. The identification of maintainer lines would be more efficient with molecular markers distinguishing genotypes at the nuclear male-fertility restoration (Ms) locus. Ms has been mapped to chromosome 2 of onion and linked genetic markers identified. However, linkages between these markers and Ms were detected using F2 or BC1 families at maximum linkage disequilibrium and, for many markers, their efficacy to predict genotypes at Ms in onion populations at or near linkage equilibrium remains unknown. In this research, near isogenic lines homozygous-dominant and -recessive at Ms were developed and screened for 930 single nucleotide polymorphisms (SNPs). Three SNPs tightly linked on chromosome 2 remained in linkage disequilibrium with genotypes at Ms among randomly selected plants from three open-pollinated populations of onion as well as among a collection of inbred lines. These SNPs should be useful for selection of the recessive ms allele to aid in the development of maintainer lines for hybrid onion development.

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