Estimating genome conservation between crop and model legume species.
Legumes are simultaneously one of the largest families of crop plants and a cornerstone in the biological nitrogen cycle. We combined molecular and phylogenetic analyses to evaluate genome conservation both within and between the two major clades of crop legumes. Genetic mapping of orthologous genes identifies broad conservation of genome macrostructure, especially within the galegoid legumes, while also highlighting inferred chromosomal rearrangements that may underlie the variation in chromosome number between these species. As a complement to comparative genetic mapping, we compared sequenced regions of the model legume Medicago truncatula with those of the diploid Lotus japonicus and the polyploid Glycine max. High conservation was observed between the genomes of M. truncatula and L. japonicus, whereas lower levels of conservation were evident between M. truncatula and G. max. In all cases, conserved genome microstructure was punctuated by significant structural divergence, including frequent insertion/deletion of individual genes or groups of genes and lineage-specific expansion/contraction of gene families. These results suggest that comparative mapping may have considerable utility for basic and applied research in the legumes, although its predictive value is likely to be tempered by phylogenetic distance and genome duplication.
Department of Plant Pathology and College of Agricultural and Environmental Sciences Genomics Facility, University of California, One Shields Avenue, Davis, CA 95616, USA.
Hong-Kyu
HK
Choi
Jeong-Hwan
JH
Mun
Dong-Jin
DJ
Kim
Hongyan
H
Zhu
Jong-Min
JM
Baek
Joanne
J
Mudge
Bruce
B
Roe
Noel
N
Ellis
Jeff
J
Doyle
Gyorgy B
GB
Kiss
Nevin D
ND
Young
Douglas R
DR
Cook
D018556:Crops, Agricultural / Q000235:genetics*; D007887:Fabaceae / Q000235:genetics*; D005819:Genetic Markers; D018745:Genome, Plant; D010802:Phylogeny; D013045:Species Specificity
D005819:Genetic Markers