Genotypic effects on the frequency of homoeologous and homologous recombination in Brassica napus × B. carinata hybrids.
We investigated the influence of genotype on homoeologous and homologous recombination frequency in eight different Brassica napus (AAC(n)C(n)) × B. carinata (BBC(c)C(c)) interspecific hybrids (genome composition C(n)C(c)AB). Meiotic recombination events were assessed through microsatellite marker analysis of 67 unreduced microspore-derived progeny. Thirty-four microsatellite markers amplified 83 A-, B-, C(n)- and C(c)-genome alleles at 64 loci, of which a subset of seven markers amplifying 26 alleles could be used to determine allele copy number. Hybrid genotypes varied significantly in loss of A- and B-genome alleles (P < 0.0001), which ranged from 6 to 22% between hybrid progeny sets. Allele copy number analysis revealed 19 A-C, 3 A-B and 10 B-C duplication/deletion events attributed to homoeologous recombination. Additionally, 55 deletions and 19 duplications without an accompanying dosage change in homoeologous alleles were detected. Hybrid progeny sets varied in observed frequencies of loss, gain and exchange of alleles across the A and B genomes as well as in the diploid C genome. Self-fertility in hybrid progeny decreased as the loss of B-genome loci (but not A-genome loci) increased. Hybrid genotypes with high levels of homologous and homoeologous exchange may be exploited for genetic introgressions between B. carinata and B. napus (canola), and those with low levels may be used to develop stable synthetic Brassica allopolyploids.
School of Plant Biology and The UWA Institute of Agriculture, Faculty of Natural and Agricultural Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia. masona02@student.uwa.edu.au
Annaliese S
AS
Mason
Matthew N
MN
Nelson
Marie-Claire
MC
Castello
Guijun
G
Yan
Wallace A
WA
Cowling
D000483:Alleles; D001937:Brassica / Q000235:genetics*; D003433:Crosses, Genetic; D005298:Fertility; D017353:Gene Deletion; D018628:Gene Dosage / Q000235:genetics; D020440:Gene Duplication / Q000235:genetics; D008040:Genetic Linkage; D056426:Genetic Loci / Q000235:genetics; D005828:Genetics, Population; D018745:Genome, Plant / Q000235:genetics; D005838:Genotype; D006824:Hybridization, Genetic; D040582:Inheritance Patterns / Q000235:genetics; D018895:Microsatellite Repeats / Q000235:genetics; D051479:Plant Infertility / Q000235:genetics; D011058:Pollen / Q000235:genetics; D011995:Recombination, Genetic; D013045:Species Specificity