Intra- and intergenomic chromosome pairings revealed by dual-color GISH in trigenomic hybrids of Brassica juncea and B. carinata with B. maurorum.
From dual-color genomic in situ hybridization (GISH) analysis of three trigenomic hybrids, Brassica maurorum (MM, 2n = 16) x B. juncea (AABB, 2n = 36) (M.AB), B. maurorum x B. carinata (BBCC, 2n = 34) (M.BC), and B. carinata x B. maurorum (BC.M), the three genomes of each hybrid were distinguished and autosyndesis and allosyndesis were evaluated. In M.AB, up to two autosyndetic bivalents occurred among the chromosomes of each genome; a maximum of three allosyndetic bivalents appeared between A-B, A-M, and B-M genomes. The similar pairings in M.BC and BC.M suggested that the cytoplasm of B. maurorum or B. carinata had no obvious effect on chromosome pairing. In M.BC and BC.M, a maximum of one autosyndetic bivalent was found for B and M genomes, but two were found for the C genome; from 0 to 2 allosyndetic bivalents were observed between B-C, B-M, and C-M genomes. The B-M allosyndesis frequency was higher than the A-M or C-M allosyndesis frequency in these hybrids, revealing the closer relationship of B and M genomes. The allosyndesis frequency was higher than the autosyndesis frequency among A, B, and C genomes in these combinations, suggesting that intergenomic homoeology was higher than intragenomic homoeology. The implications for genome evolution and crop breeding are discussed.
National Key Laboratory of Crop Genetic Improvement, National Center of Crop Molecular Breeding Technology, National Center of Oil Crop Improvement (Wuhan), College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, P.R. China.
X C
XC
Yao
X Z
XZ
Du
X H
XH
Ge
J P
JP
Chen
Z Y
ZY
Li
D001937:Brassica / Q000235:genetics*; D002678:Chimera / Q000235:genetics*; D002874:Chromosome Mapping / Q000379:methods; D023902:Chromosome Pairing / Q000502:physiology*; D003116:Color; D003434:Crossing Over, Genetic / Q000235:genetics; D005456:Fluorescent Dyes / Q000494:pharmacology; D018745:Genome, Plant; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D009149:Mustard Plant / Q000235:genetics; D011995:Recombination, Genetic / Q000235:genetics
D005456:Fluorescent Dyes