Latent S alleles are widespread in cultivated self-compatible Brassica napus

Genome ◽  
2004 ◽  
Vol 47 (2) ◽  
pp. 257-265 ◽  
Author(s):  
U U Ekuere ◽  
I A.P Parkin ◽  
C Bowman ◽  
D Marshall ◽  
D J Lydiate

The genetic control of self-incompatibility in Brassica napus was investigated using crosses between resynthesized lines of B. napus and cultivars of oilseed rape. These crosses introduced eight C-genome S alleles from Brassica oleracea (S16, S22, S23, S25, S29, S35, S60, and S63) and one A-genome S allele from Brassica rapa (SRM29) into winter oilseed rape. The inheritance of S alleles was monitored using genetic markers and S phenotypes were determined in the F1, F2, first backcross (B1), and testcross (T1) generations. Two different F1 hybrids were used to develop populations of doubled haploid lines that were subjected to genetic mapping and scored for S phenotype. These investigations identified a latent S allele in at least two oilseed rape cultivars and indicated that the S phenotype of these latent alleles was masked by a suppressor system common to oilseed rape. These latent S alleles may be widespread in oilseed rape varieties and are possibly associated with the highly conserved C-genome S locus of these crop types. Segregation for S phenotype in subpopulations uniform for S genotype suggests the existence of suppressor loci that influenced the expression of the S phenotype. These suppressor loci were not linked to the S loci and possessed suppressing alleles in oilseed rape and non-suppressing alleles in the diploid parents of resynthesized B. napus lines.Key words: self-incompatibility, B. oleracea, B. rapa, S locus, suppression.

Genome ◽  
1995 ◽  
Vol 38 (6) ◽  
pp. 1112-1121 ◽  
Author(s):  
A. G. Sharpe ◽  
I. A. P. Parkin ◽  
D. J. Keith ◽  
D. J. Lydiate

A RFLP map of Brassica napus, consisting of 277 loci arranged in 19 linkage groups, was produced from genetic segregation in a combined population of 174 doubled-haploid microspore-derived lines. The integration of this map with a B. napus map derived from a resynthesized B. napus × oilseed rape cross allowed the 10 linkage groups of the B. napus A genome and the 9 linkage groups of the C genome to be identified. Collinear patterns of marker loci on different linkage groups suggested potential partial homoeologues. RFLP patterns consistent with aberrant chromosomes were observed in 9 of the 174 doubled-haploid lines. At least 4 of these lines carried nonreciprocal, homoeologous translocations. These translocations were probably the result of homoeologous recombination in the amphidiploid genome of oilseed rape, suggesting that domesticated B. napus is unable to control chromosome pairing completely. Evidence for genome homogenization in oilseed rape is presented and its implications on genetic mapping in amphidiploid species is discussed. The level of polymorphism in the A genome was higher than that in the C genome and this might be a general property of oilseed rape crosses.Key words: restriction fragment length polymorphism, genetic linkage map, homoeologous recombination, microspore culture, doubled haploid.


1985 ◽  
Vol 27 (6) ◽  
pp. 710-715 ◽  
Author(s):  
R. Ayotte ◽  
P. M. Harney ◽  
B. R. Christie

Self-incompatible and self-compatible lines of Brassica napus L. were crossed and the compatibility status of the F1 and F2 progeny assessed. Compatibility was established by measuring silique and seed set and by microscopic examination of self-pollen behaviour on the stigma and within the style of flowers. Microscopic evaluation was found to be unreliable in determining whether seed set would occur on a plant following self-pollination. The F1 data could not be interpreted because turnip mosaic virus in the greenhouse killed many plants and may have affected the compatibility reaction of the rest. Silique set data for the F2 showed one line (Z) segregated 3:1 self-incompatible to self-compatible, indicating only one locus involved. The 10:6 self-compatible to self-incompatible ratio, obtained for a second line (R) can be explained in the same manner if a dominant modifier (M), which interacts only with S-allele heteozygotes, is also present.Key words: rutabaga, Brassica napus, self-incompatibility, S alleles, genetic.


Genome ◽  
1995 ◽  
Vol 38 (6) ◽  
pp. 1122-1131 ◽  
Author(s):  
I. A. P. Parkin ◽  
A. G. Sharpe ◽  
D. J. Keith ◽  
D. J. Lydiate

A genetic linkage map consisting of 399 RFLP-defined loci was generated from a cross between resynthesized Brassica napus (an interspecific B. rapa × B. oleracea hybrid) and "natural" oilseed rape. The majority of loci exhibited disomic inheritance of parental alleles demonstrating that B. rapa chromosomes were each pairing exclusively with recognisable A-genome homologues in B. napus and that B. oleracea chromosomes were pairing similarly with C-genome homologues. This behaviour identified the 10 A genome and 9 C genome linkage groups of B. napus and demonstrated that the nuclear genomes of B. napus, B. rapa, and B. oleracea have remained essentially unaltered since the formation of the amphidiploid species, B. napus. A range of unusual marker patterns, which could be explained by aneuploidy and nonreciprocal translocations, were observed in the mapping population. These chromosome abnormalities were probably caused by associations between homoeologous chromosomes at meiosis in the resynthesized parent and the F1 plant leading to nondisjunction and homoeologous recombination.Key words: genetic linkage map, homoeologous recombination, Brassica rapa, Brassica oleracea, genome organization.


2005 ◽  
Vol 11 (1) ◽  
Author(s):  
A. Pedryc ◽  
J. Halász ◽  
R. Hermán ◽  
A. Hegedűs

Self-incompatibility (SI) in flowering plants is a widespread genetic system that promotes out-crossing. In Prunus species the SI is a gametophytic trait, which is controlled by a single multiallelic locus, termed S-locus. S-alleles codify stylar glycoproteins with ribonuclease activity (S-RNases). Our objective was to assess the S-genotype of some Hungarian apricot varieties by isoelectric focusing of stylar RNases as well as by PCR analysis using cherry consensus primers. Consensus primers amplified one or two bands of various sizes. Primers amplifying the 1st intron gained fragments the size of which ranged from 250 to 500 bp; while those amplifying the 2nd intron resulted in fragments of 800-2000 by length. Our data demonstrated that the first intron of the apricot S-RNase gene is shorter than the second one, which coincides with the structure of cherry S-RNase alleles. `Hargrand' (S1S2) and `Harcoe (S1S4) possessed one common S-RNase isoenzyme. Hungarian 'Orias' apricot cultivars showed different bands compared to the previous cultivars, but they shared completely identical patterns confirming that they possess the same S-genotype. 'Bergeron', `Harmat' and 'Korai zamatos' are characterised by an evidently distinct S-RNase pattern. The self-compatible cultivar (`Bergeron') had one allele, which suggests its correspondence to the Sc. Primers for the 2nd intron was unsuccessful in gaining fragments, which indicates that the 2nd intron in the Sc allele is too long to get any amplification. On the basis of our data, identities and differences were revealed in the S-allele constitution of some economically important Hungarian apricot cultivars at protein and DNA levels.


2018 ◽  
Vol 97 (5) ◽  
pp. 1389-1406 ◽  
Author(s):  
Farshad Fattahi ◽  
Barat Ali Fakheri ◽  
Mahmood Solouki ◽  
Christian Möllers ◽  
Abbas Rezaizad

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