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.
Choi
Hong-Kyu
HK
Department of Plant Pathology and College of Agricultural and Environmental Sciences Genomics Facility, University of California, One Shields Avenue, Davis, CA 95616, USA.
Mun
Jeong-Hwan
JH
Kim
Dong-Jin
DJ
Zhu
Hongyan
H
Baek
Jong-Min
JM
Mudge
Joanne
J
Roe
Bruce
B
Ellis
Noel
N
Doyle
Jeff
J
Kiss
Gyorgy B
GB
Young
Nevin D
ND
Cook
Douglas R
DR
D018556:Crops, Agricultural / Q000235:genetics*; D007887:Fabaceae / Q000235:genetics*; D005819:Genetic Markers; D018745:Genome, Plant; D010802:Phylogeny; D013045:Species Specificity
D005819:Genetic Markers