Meiotic behaviour of extra chromosomes in fertility restored Polima CMS Brassica napus plants

Genome ◽  
1988 ◽  
Vol 30 (3) ◽  
pp. 438-442 ◽  
Author(s):  
William Tai ◽  
Peter B. E. McVetty
Keyword(s):  
Brassica Napus ◽  
Fertility Restoration ◽  
Extra Chromosome ◽  
Pollen Grains ◽  
Backcross Progeny ◽  
Male Sterile ◽  
High Frequencies ◽  
B Genome ◽  
Mother Cells ◽  
Very High Frequencies

Crosses were made between Brassica napus (2n = 38) with the 'Polima' cytoplasmic male sterile system and variety 'Zem' of B. juncea. Fertility was partially restored in backcross progeny with an extra chromosome (2n = 39) that was believed to be a member of the B genome of B. juncea. Among more than 40 self-pollinated offspring plants studied, fertility restoration was transmitted only through those plants with two extra chromosomes (2n = 40). Anthers of these plants were either full or shriveled with small swollen protrusions. Full and round pollen grains were found in full anthers and in the swollen portion of shriveled anthers. These pollen grains were stained darkly with I2-KI solution and full seed set was obtained from bagged flowers. Meiotic studies in plants with 2n = 40 showed 18 bivalents + 1 quadrivalent at diakinesis in most of the pollen mother cells analyzed. The chromosomes segregated equally at anaphase I and behaved normally at other meiotic stages. The presence of a single quadrivalent in the backcross progeny was highly consistent and occurred in very high frequencies. It is believed that the extra chromosomes belong to the B genome of B. juncea and take part in the quadrivalent formation.Key words: Brassica napus, cytoplasmic male sterility, aneuploidy, Polima, Brassica juncea, rapeseed cytogenetics.

Male sterility in Brassica napus L. associated with an extra chromosome

1985 ◽  
Vol 27 (4) ◽  
pp. 467-471 ◽  
Author(s):  
Z. Fan ◽  
W. Tai ◽  
B. R. Stefansson
Keyword(s):  
Brassica Napus ◽  
Male Sterility ◽  
Extra Chromosome ◽  
Female Parent ◽  
Male Sterile ◽  
Cytological Examination ◽  
Brassica Napus L ◽  
Low Frequencies ◽  
Backcross Populations ◽  
Mother Cells

Male sterility was investigated in backcross populations from hybrids between Diplotaxis muralis and Brassica napus using the former as the female parent. The F1 was male sterile and low frequencies (less than 20%) of male sterile plants were obtained from subsequent backcross generations. The data did not fit any Mendelian genetic ratios. Cytological examination of pollen mother cells from 52 plants of these backcross populations indicated the presence of an extra chromosome in all 22 male sterile plants and the normal chromosome number (2n = 38) in the remaining 30 fertile plants. Thus an extra chromosome which is derived from Diplotaxis muralis appears to be the sole cause of male sterility in these backcross populations.Key words: male sterility, Brassica napus, Diplotaxis muralis.

scholarly journals CYTOGENETICS OF FLOWER MODIFICATION OF A CYTOPLASMIC MALE-STERILE TOBACCO

Genetics ◽  
1980 ◽  
Vol 96 (1) ◽  
pp. 223-235
Author(s):  
D U Gerstel ◽  
J A Burns ◽  
S A Sand
Keyword(s):  
Extra Chromosome ◽  
Backcross Progeny ◽  
Chromosome Segment ◽  
Flower Structure ◽  
Male Sterile ◽  
Normal Morphology ◽  
Partial Restoration ◽  
Transmission Rates ◽  
Normal Males ◽  
Nicotiana Debneyi

ABSTRACT Plants combining the cytoplasm of Nicotiana debneyi and the 48 chromosomes from N. tabacum are male sterile. Early backcross generations of the amphidiploid hybrid to male N. tabacum produced a great variety of plants from which a series of phenotypes with characteristic flower forms and transmission rates have been isolated. Type 1A possesses completely feminized stamens and deeply split corollas, breeds true when backcrossed to normal males and carries 48 N. tabacum chromosomes. Other phenotypes, 2C, 3E and 4H, range toward normal morphology of corollas and stamens. Like 1A, 2C forms no anther tissue and has 48 chromosomes. This type is transmitted to 36.3% of the backcross progeny, the remainder being of type 1A; presumably 2C carries a chromosome segment from N. debneyi that is responsible for the partial restoration of flower structure. In contrast, both 3E and 4H produce anthers and possess an extra chromosome. The extra chromosomes are transmitted to only 19.9% and 7.1% of the progeny, respectively. Significantly, the extra chromosomes found in the anther-forming types are nucleolus organizing and carry a satellite from N. debneyi. On the basis of these observations, we surmise that differentiation of anthers in plants with N. debneyi cytoplasm may depend on the presence of a nucleolus-organizing chromosome from that species. This chromosome is unstable; unaltered, it conditions a highly restored phenotype (4H), but when structurally modified, it may control different phenotypic expressions. Other examples of satellited restorer chromosomes had been reported for different cytoplasmically male-sterile combinations; therefore, the phenomenon may have more general significance.

Chromosomal Differentiation Among Ecotypes of Phalaris aquatica L.

1980 ◽  
Vol 28 (6) ◽  
pp. 645 ◽  
Author(s):  
E Putievsky ◽  
RN Oram ◽  
K Malafant
Keyword(s):  
Pollen Grains ◽  
F1 Hybrids ◽  
Male Sterile ◽  
Geographic Origins ◽  
Meiotic Irregularities ◽  
Structural Differences ◽  
Two Generations ◽  
Chromosomal Differentiation ◽  
Mother Cells ◽  
F2 Progeny

Seventy-two hybrids of P. aquatica were made among 13 diverse Mediterranean ecotypes and cv. Australian, and five indicators of hybrid abnormality were measured in the first two generations. The proportions of stainable, apparently normal pollen grains formed by F, hybrids varied between 5 and 98% and their spikelet fertility ranged from 19 to 77%. Of the 43 hybrids that were derived from pairs of self-incompatible parents, 13 were highly self-compatible. Crosses between lines from different groups of parents produced F2 progeny containing up to 17% of lethal seedlings and up to 39% of male sterile plants. In the cross between cv. Australian and the Moroccan ecotype, CPI 19331: the frequency ofzebra-striped lethal seedlings was as high as 33% in F2 progenies, but only 0 or 1% in back-crosses to either parent. Hence the zebra-striped phenotype was not caused by a mutation existing in the parents but rather by deletions or duplications generated during meiosis in the F1 hybrids. Many meiotic irregularities were observed in the pollen mother cells of the F1 and F2 hybrids between cv. Australian and CPI 19331. These included small loops, acentric fragments, univalents and multivalents at diakinesis, and bridges at anaphase I, indicating that the genomes of these two lines differed by several inversions and interchanges. These structural differences would lead to a range of duplications and deficiencies in the gametes. and hence could account for each of the five kinds of hybrid abnormality observed in the F1 and F2 generations. One aneuploid F2 plant with 25 chromosomes was found. A dihaploid plant in cv. Australian had an average of 4.3 bivalents per pollen mother cell, whereas virtually all chromosomes in the tetraploid parental lines paired as bivalents. Thus, P. aquatica is a segmental allotetraploid with a system which prevents homoeologous pairing in tetraploids but not in dihaploids. The partial barriers to hybridization between P. aquatica lines are not closely related to their geographic origins or varietal classifications. These barriers may hinder but have not prevented the recombination of parental traits during the development of improved cultivars.

Incorporation of restoring gene of Aegilops umbellulata into wheat

Genome ◽  
1991 ◽  
Vol 34 (5) ◽  
pp. 727-732 ◽  
Author(s):  
Zheng-Qiang Ma ◽  
Yin-Hai Zhao ◽  
Da-Jun Liu
Keyword(s):  
Chinese Spring ◽  
Fertility Restoration ◽  
Triticum Aestivum L ◽  
Addition Line ◽  
Male Sterile ◽  
Aegilops Umbellulata ◽  
Alien Gene ◽  
Mother Cells ◽  
Type Chromosome ◽  
Heterozygous Translocation

Six 'Chinese Spring' – Aegilops umbellulata Zhuk. addition lines (UAD, UBD, UCD, UDD, UED, and UFM) were assayed for their effects on the fertility of timopheevi cytoplasm male sterile lines (T-type). Chromosome 6U of disomic addition line UAD was found to be able to restore the fertility of T-type male sterility and 'Chinese Spring' was verified to lack restoring genes, indicating that 6U carries at least one fertility restoration gene. From about 200 plants with 42 somatic chromosomes derived from the progeny of crosses Qu Xian Early A × UAD and Sumai No. 3 A × UAD, eight self-fertile plants were selected. Their self-fertility in timopheevi cytoplasm implies that they carry the restoring gene(s) from 6U. Cytological analysis was conducted on the hybrid F1 of the selected fertile plants (040-5, 060-1, and 061-4) as female parents crossed with 'Chinese Spring'. The self-fertility segregation and the chromosome pairing of pollen mother cells of F1 fertile plants from 040-5, 060-1, and 061-4 × 'Chinese Spring' during meiosis suggested that they were heterozygous translocation lines with restoring gene(s) from 6U.Key words: Aegilops umbellulata Zhuk., restoring genes, alien gene transfer, timopheevi cytoplasmic male sterile fertility, Triticum aestivum L.

scholarly journals Unraveling the Genetic Basis of Fertility Restoration for Cytoplasmic Male Sterile Line WNJ01A Originated From Brassica juncea in Brassica napus

2021 ◽  
Vol 12 ◽  
Author(s):  
Qian Yang ◽  
Xiaoyi Nong ◽  
Jize Xu ◽  
Fan Huang ◽  
Fang Wang ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Bulked Segregant Analysis ◽  
Fertility Restoration ◽  
26S Proteasome ◽  
Morphological Observation ◽  
Male Sterile ◽  
Bac Clone ◽  
Cell Stage ◽  
Cms Line ◽  
Candidate Interval

Crosses that lead to heterosis have been widely used in the rapeseed (Brassica napus L.) industry. Cytoplasmic male sterility (CMS)/restorer-of-fertility (Rf) systems represent one of the most useful tools for rapeseed production. Several CMS types and their restorer lines have been identified in rapeseed, but there are few studies on the mechanisms underlying fertility restoration. Here, we performed morphological observation, map-based cloning, and transcriptomic analysis of the F2 population developed by crossing the CMS line WNJ01A with its restorer line Hui01. Paraffin-embedded sections showed that the sporogenous cell stage was the critical pollen degeneration period, with major sporogenous cells displaying loose and irregular arrangement in sterile anthers. Most mitochondrial electron transport chain (mtETC) complex genes were upregulated in fertile compared to sterile buds. Using bulked segregant analysis (BSA)-seq to analyze mixed DNA pools from sterile and fertile F2 buds, respectively, we identified a 6.25 Mb candidate interval where Rfw is located. Using map-based cloning experiments combined with bacterial artificial chromosome (BAC) clone sequencing, the candidate interval was reduced to 99.75 kb and two pentatricopeptide repeat (PPR) genes were found among 28 predicted genes in this interval. Transcriptome sequencing showed that there were 1679 DEGs (1023 upregulated and 656 downregulated) in fertile compared to sterile F2 buds. The upregulated differentially expressed genes (DEGs) were enriched in the Kyoto Encyclopedia of Genes and Genomes (KEGG) lysine degradation pathway and phenylalanine metabolism, and the downregulated DEGs were enriched in cutin, suberine, and wax biosynthesis. Furthermore, 44 DEGs were involved in pollen and anther development, such as tapetum, microspores, and pollen wall development. All of them were upregulated except a few such as POE1 genes (which encode Pollen Ole e I allergen and extensin family proteins). There were 261 specifically expressed DEGs (9 and 252 in sterile and fertile buds, respectively). Regarding the fertile bud-specific upregulated DEGs, the ubiquitin–proteasome pathway was enriched. The top four hub genes in the protein–protein interaction network (BnaA09g56400D, BnaA10g18210D, BnaA10g18220D, and BnaC09g41740D) encode RAD23d proteins, which deliver ubiquitinated substrates to the 26S proteasome. These findings provide evidence on the pathways regulated by Rfw and improve our understanding of fertility restoration.

scholarly journals Resynthesis of new R lines in Brassica napus L.

2016 ◽  
Vol 41 (3) ◽  
pp. 529-540
Author(s):  
MA Miah ◽  
MG Rasul ◽  
MAK Mian
Keyword(s):  
Brassica Napus ◽  
Fertility Restoration ◽  
Winter Season ◽  
Nuclear Gene ◽  
Restorer Line ◽  
Male Sterile ◽  
Brassica Napus L ◽  
F1 Hybrid ◽  
First Case ◽  
F2 Generation

Identification of male fertility restorer genotypes for rapeseed CMS lines towards hybrid development in spring habit rapeseed (Brassica napus L.) adapted for short day winter season was studied. The experiment was conducted at the experimental farm and laboratory of Bangabandhu Sheikh Mujibur Rahman Agricultural University, Salna, Gazipur during October, 2008 to March, 2011. An exotic CMS-based F1 hybrid of rapeseed was selfed to get F2 generation with a view to resynthesizing restorer line. As a result a restorer line for Nap248A Z1 and Nap248A Z2 cytoplasmic male sterile lines was identified in the F3 generation of the exotic F1 rapeseed hybrid which appears as the first case so far reported as achievement in Bangladesh in this regard. Genetic analysis further revealed fertility restoration for Nap248A Z1 and Nap248A Z2 cytoplasmic male sterility was controlled by a single dominant nuclear gene as a simple genetic phenomenon.Bangladesh J. Agril. Res. 41(3): 529-540, September 2016

Alloplasmic male sterile Brassica napus with Enarthrocarpus lyratus cytoplasm: introgression and molecular mapping of an E. lyratus chromosome segment carrying a fertility restoring gene

Genome ◽  
2003 ◽  
Vol 46 (5) ◽  
pp. 792-797 ◽  
Author(s):  
H S Janeja ◽  
S K Banga ◽  
P B Bhaskar ◽  
S S Banga
Keyword(s):  
Brassica Napus ◽  
Cytoplasmic Male Sterility ◽  
Male Sterility ◽  
Molecular Mapping ◽  
Bulked Segregant Analysis ◽  
Fertility Restoration ◽  
Hybrid Seed Production ◽  
Male Sterile ◽  
Fertility Restorer ◽  
Donor Species

A cytoplasmic male sterility (CMS) system for Brassica napus (2n = 38; AACC) was developed by backcross substitution of its nucleus into the cytoplasm of a wild crucifer, Enarthrocarpus lyratus. Male sterility was complete, stable, and expressed in small flowers with rudimentary anthers. Since the B. napus germplasm lines were complete or partial maintainers of male sterility, the required fertility restorer gene (Rfl) was introgressed from the cytoplasm donor species. Inheritance studies carried out on F1 and F2 populations derived from hybridizing cytoplasmic male sterile and male fertile near-isogenic (PNILs) lines of B. napus 'Westar', revealed a monogenic dominant control for fertility restoration. Bulked segregant analysis with 215 RAPD primers helped in the identification of putative primers associated with fertility restoration. Co-segregation analysis of eight such primers with Rfl gene revealed two markers, OPK 15700 and OPZ 061300, which flank the Rfl locus on either side at a distance of 8.2 and 2.5 cM, respectively. These DNA markers will be useful in marker-assisted selection for improving the commercial potential of this newly developed CMS-fertility-restorer system for hybrid seed production programs in rapeseed.Key words: oilseed rape, hybrids, cytoplasmic male sterility, fertility restoration, RAPD mapping.

scholarly journals Slowing Development Facilitates Arabidopsis mgt Mutants to Accumulate Enough Magnesium for Pollen Formation and Fertility Restoration

2021 ◽  
Vol 11 ◽  
Author(s):  
Xiao-Feng Xu ◽  
Xue-Xue Qian ◽  
Kai-Qi Wang ◽  
Ya-Hui Yu ◽  
Yu-Yi Guo ◽  
...  
Keyword(s):  
Fertility Restoration ◽  
Pollen Grains ◽  
General Mechanism ◽  
Wild Type ◽  
Pollen Mitosis ◽  
Male Sterile ◽  
Pollen Abortion ◽  
Slow Development ◽  
Magnesium Transporter ◽  
Pollen Formation

Magnesium (Mg) is an abundant and important cation in cells. Plants rely on Mg transporters to take up Mg from the soil, and then Mg is transported to anthers and other organs. Here, we showed that MGT6+/− plants display reduced fertility, while mgt6 plants are fertile. MGT6 is expressed in the anther at the early stages. Pollen mitosis and intine formation are impaired in aborted pollen grains (PGs) of MGT6+/− plants, which is similar to the defective pollen observed in mgt5 and mgt9 mutants. These results suggest that Mg deficiency leads to pollen abortion in MGT6+/− plants. Our data showed that mgt6 organs including buds develop significantly slower and mgt6 stamens accumulate a higher level of Mg, compared with wild-type (WT) and MGT6+/− plants. These results indicate that slower bud development allows mgt6 to accumulate sufficient amounts of Mg in the pollen, explaining why mgt6 is fertile. Furthermore, we found that mgt6 can restore fertility of mgt5, which has been reported to be male sterile due to defects in Mg transport from the tapetum to microspores and that an additional Mg supply can restore its fertility. Interestingly, mgt5 fertility is recovered when grown under short photoperiod conditions, which is a well-known factor regulating plant fertility. Taken together, these results demonstrate that slow development is a general mechanism to restore mgts fertility, which allows other redundant magnesium transporter (MGT) members to transport sufficient Mg for pollen formation.

A cytogenetic study of monosomics in Brassica napus L.

1985 ◽  
Vol 27 (6) ◽  
pp. 683-688 ◽  
Author(s):  
Zhegong Fan ◽  
William Tap
Keyword(s):  
Brassica Napus ◽  
Brassica Juncea ◽  
Centromeric Region ◽  
Cytogenetic Study ◽  
Pollen Grains ◽  
Meiotic Behavior ◽  
Cytological Examination ◽  
Brassica Napus L ◽  
Small Pollen ◽  
Mother Cells

Two types of monosomic plants of Brassica napus L. were discovered among the backcross progenies of crosses between Diplotaxis muralis L. and B. napus and between Brassica juncea L. and B. napus. These monosomics were designated mono-1 and mono-2, respectively. Morphologically the monosomic plants were virtually indistinguishable from their sib disomic plants. Seed production on both mono-1 and mono-2 plants was normal. Cytological examination revealed that most pollen mother cells (85%) of mono-1 plants formed 18 bivalents plus one univalent at diakinesis, while the remainder (15%) formed 17 bivalents plus a trivalent. The univaltn in mono-1 was submetacentric and its two arms were always stained more lightly than the centromeric region. Later meiotic stages in mono-1 plants appeared normal. The plants of mono-1 produced two types of pollen grains which were different in size. Both the large and small pollen grains of mono-1 were deeply stained with an I2–KI solution. Meiotic behavior of mono-2 plants was similar to that of mono-1 plants, but the frequency of trivalent formation was higher (62%). The univalent in mono-2 was longer than the two chromosomes it paired with to form a trivalent. Pollen produced on mono-2 plants was uniform in size and comparable to that of the normal disomics.Key words: Brassica napus, Brassica juncea, Diplotaxis muralis, aneuploidy, monosomics.

MAINTAINERS AND RESTORERS FOR THREE MALE-STERILITY-INDUCING CYTOPLASMS IN RAPE (Brassica napus L.)

1986 ◽  
Vol 66 (2) ◽  
pp. 229-234 ◽  
Author(s):  
Z. Fan ◽  
B. R. STEFANSSON ◽  
J. L. SERNYK
Keyword(s):  
Brassica Napus ◽  
Male Sterility ◽  
Male Fertility ◽  
Extra Chromosome ◽  
Dominant Gene ◽  
Male Sterile ◽  
Brassica Napus L ◽  
Self Pollination ◽  
Selection For ◽  
Restoration Of Fertility

The F1 progenies from crosses involving 32 Brassica napus L. strains (including named cultivars) and male-sterile plants carrying one of the three cytoplasms, ogu, nap, and pol were evaluated for male fertility. All strains were found to be maintainers for the ogu cytoplasm. The fertility of the nap male-sterile plants were fully restored by 30 strains. The cultivar Bronowski partially maintained the nap male sterility, and segregation for male fertility/sterility was observed in the F1 hybrid between nap male sterile plants and the cultivar Lergo. Lergo, therefore, appears to be heterogeneous for genes conditioning maintenance and restoration of this type of male sterility. Most strains were maintainers and the balance were partial maintainers for the pol cytoplasm. The F2 and backcross data obtained under a controlled environment suggest that both the cultivars Karat and Westar possess a single dominant gene for the restoration of fertility in nap cytoplasm. Fertility in the pol cytoplasm was restored in the F1 of crosses between pol B. napus and the B. juncea L. Czern. cultivar ZEM. Five male fertile lines of pol B. napus were selected from the ZEM crosses after five generations of backcrossing to B. napus cultivar Regent and three generations of self-pollination. Selection for fertility during backcrossing and self-pollination resulted in selection for an extra chromosome involved with male fertility restoration.Key words: Rape, Brassica napus L., CMS, maintainers, restorers

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