Mapping PrBn and other quantitative trait loci responsible for the control of homeologous chromosome pairing in oilseed rape (Brassica napus L.) haploids.
In allopolyploid species, fair meiosis could be challenged by homeologous chromosome pairing and is usually achieved by the action of homeologous pairing suppressor genes. Oilseed rape (Brassica napus) haploids (AC, n=19) represent an attractive model for studying the mechanisms used by allopolyploids to ensure the diploid-like meiotic pairing pattern. In oilseed rape haploids, homeologous chromosome pairing at metaphase I was found to be genetically based and controlled by a major gene, PrBn, segregating in a background of polygenic variation. In this study, we have mapped PrBn within a 10-cM interval on the C genome linkage group DY15 and shown that PrBn displays incomplete penetrance or variable expressivity. We have identified three to six minor QTL/BTL that have slight additive effects on the amount of pairing at metaphase I but do not interact with PrBn. We have also detected a number of other loci that interact epistatically, notably with PrBn. Our results support the idea that, as in other polyploid species, metaphase I homeologous pairing in oilseed rape haploids is controlled by an integrated system of several genes, which function in a complex manner.
Liu
Zhiqian
Z
UMR INRA-Agrocampus Rennes, Amélioration des Plantes et Biotechnologies Végétales, Le Rheu, France.
Adamczyk
Katarzyna
K
Manzanares-Dauleux
Maria
M
Eber
Frédérique
F
Lucas
Marie-Odile
MO
Delourme
Régine
R
Chèvre
Anne Marie
AM
Jenczewski
Eric
E
D029688:Brassica napus / Q000235:genetics*; D023902:Chromosome Pairing; D032461:Chromosomes, Plant; D005819:Genetic Markers; D006238:Haploidy; D021141:Nucleic Acid Amplification Techniques / Q000379:methods; D020161:Physical Chromosome Mapping; D011110:Polymorphism, Genetic; D040641:Quantitative Trait Loci
D005819:Genetic Markers