The Lotus japonicus Genome

3

Genetic Linkage Maps, Synteny

and Map-based Cloning

Niels Sandal and Shusei Sato

Abstract

Nitrogenfixation is a very important trait in agriculture and nature. It is

made possible through symbiosis between plants, mainly legumes, and

microorganisms such as rhizobia. Like most plants, legumes have

symbiosis with mycorrhizal fungi. In order to isolate the plant genes

that are important for symbiosis with nitrogen-fixing organisms and

mycorrhizal symbiosis,Lotus japonicuswas suggested as a model legume

by Handberg and Stougaard ( 1992 ).

3.1 Mapping with Crosses
BetweenL. japonicusGifu
andL. japonicusFunakura
andL. filicaulis

Mapping and map-based cloning are a very
powerful procedure to isolate genes based on
phenotypes of mutants and species/ecotypes and
molecular markers. Therefore, mutant isolation
and mapping inLotuswere initiated. For map-
ping, you need differences at the DNA and

phenotypic levels. Handberg and Stougaard

elected to work on the ecotype Gifu B-129

(growing in the Gifu prefecture in the middle of

Japan) (Stougaard and Beuselinck 1996 ). Many

of theLotus japonicusmutants have been made

in the Gifu ecotype. To initiate mapping, poly-

morphic (with differences at the DNA level)

ecotype(s)/species had to be found. The level of

polymorphisms in the different ecotypes known

at that time did not appear to be high, but Fu-

nakura was used as a mapping partner by Jiang

and Gresshoff ( 1997 ). Grant and co-workers

from Canada showed that several diploid species

ofLotuscan be crossed withL. japonicusand

give fertile offspring (de Nettancourt and Grant

1964 ; Somaroo and Grant 1971 ). One of the best

crossing partners turned out to beL.filicaulis,

which originates from Algeria (de Nettancourt

and Grant 1964 ; Sandal et al. 2002 , 2006 ). This

was the basis of one of thefirst F2 mapping

populations inLotus. When no sequence data are

available, the amplified fragment length poly-

morphism (AFLP) technique is very powerful as

many polymorphic AFLP markers can be found

N. Sandal (&)
Centre for Carbohydrate Recognition and Signalling,
Department of Molecular Biology and Genetics,
Aarhus University, Gustav Wieds Vej 10,
8000 Aarhus C, Denmark
e-mail: [email protected]

S. Sato
Graduate School of Life Sciences, Tohoku
University, Katahira 2-1-1, Aoba-ku, Sendai
980-8577, Japan
e-mail: [email protected]

S. Tabata and J. Stougaard (eds.),The Lotus japonicus Genome, Compendium of Plant Genomes,
DOI 10.1007/978-3-662-44270-8_3,©Springer-Verlag Berlin Heidelberg 2014

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