the development of sustainable agriculture is a major challenge 
 for humanity : we could eradicate hunger from the 
 earth but still preserve our planet for coming generations , 
 for example by using less pesticides and chemical fertilizers , 
 reducing the greenhouse effect , maintaining small 
 farming communities , preserving biodiversity .
it is clear 
 that legumes can provide a solution : in terms of protein 
 content they are amongst the richest plants in the world , 
 and they contribute to feeding the majority of the inhabitants 
 of developing countries .
thanks to symbiotic nitrogen 
 fixation , legumes do not need nitrogenous fertilizers , 
 production of which consumes petroleum and which contribute 
 significantly to groundwater pollution as well as to 
 the greenhouse effect .
last but not least , legumes are very 
 rich in molecules that have potential pharmaceutical uses . 

as stated by rodomiro ortiz ( international institute of 
 tropical agriculture , kampala , uganda ) " food legumes are 
 a gold - mine for the developing world " , but their productivity 
 remains limited by a lack of access to , and control of , 
 water resources . as a joint meeting , the conference brought together for the 
 first time researchers working on improving grain - legume 
 breeding and processing with those using modern genomic 
 strategies on model plants .
jean - jacques drevon ( inra , 
 montpelier , france ) identified the central theme of the 
 conference as " how to link genomics and agronomy " . over 
 five days
, 450 participants from 45 countries tried to 
 provide answer(s ) to this question .
it should be noted , 
 however , that the attendance came essentially from developed countries - fewer than 4% of participants came from africa , 
 for example .
this report focuses on a few of the presentations 
 that illustrate the multidisciplinary nature of current 
 research into the genetics and genomics of legumes .
the large diversity of legume species initially encouraged 
 researchers to develop two model legumes : medicago 
 truncatula and lotus japonicus .
it now appears that , contrary 
 to early concerns , having two model legumes does not 
 necessarily lead to a duplication of results but , in fact , 
 often leads to an acceleration of research by creating complementary 
 and synergistic approaches between the two 
 research communities .
paul , usa ) presented persuasive evidence that 
 the m. truncatula genome is organized into distinct 
 regions of gene - rich euchromatin and repeat - rich pericentromeric 
 heterochromatin .
thus , sequencing the gene - space 
 of m. truncatula can be performed efficiently using a 
 bac - by - bac strategy , making use of bacterial artificial 
 chromosomes ( bacs ) anchored in the expressed genome . 

young went on to describe the organization of the international 
 sequencing consortium , which comprises groups 
 from the usa and eu and is expected to finish sequencing 
 the gene - space of m. truncatula by the end of 2006 
 ( further details on this sequencing project can be found at 
 ) .
most plant species form symbiotic associations , known as 
 mycorrhizae , between their roots and fungi .
helge kuester 
 ( university of bielefeld , germany ) reported studies using 
 oligonucleotide microarrays to characterize the transcriptome 
 of a particular type of mycorrhizal symbiosis - arbuscular 
 mycorrhiza - formed by m. truncatula in response to 
 two different species of glomus fungi .
a subset of 205 
 genes , including several novel transcriptional regulators , 
 was found to be induced in both endosymbioses .
interestingly , in addition to these co - induced genes , several hundred 
 genes were activated only by one or the other species of 
 symbiotic fungus , indicating that the plant transcriptome 
 in arbuscular mycorrhiza roots is strongly dependent on 
 the nature of the infecting microsymbiont .
root hairs are 
 specialized outgrowths of epidermal cells of the root that 
 represent an essential interface between the plant and the 
 soil for nutrient and water uptake .
gary stacey 's group 
 ( university of missouri , columbia , usa ) was able to isolate 
 gram quantities of soybean root hairs , and therefore open 
 the door to future dna microarray and proteomic studies 
 of legume root - hair infection by rhizobia .
measurement and identification of the metabolome allows 
 various issues to be addressed , such as the influence of 
 genotype , genetic modifications and stress factors on a 
 plant 's behavior .
adrian charlton ( central science laboratory , 
 york , uk ) uses nuclear magnetic resonance ( nmr ) spectroscopy 
 to study the pea leaf metabolome and is able to 
 discriminate between members of the germplasm collection 
 maintained at the john innes centre ( norwich , uk ) 
 and between plants subjected to different watering 
 regimes .
ole sgaard lund ( danish institute of agricultural 
 sciences , slagelse , denmark ) described the transferal 
 to legumes of another technology , virus induced gene 
 silencing ( vigs ) .
his group has inoculated pea plants with 
 constructs combining the tobravirus pea early - browning 
 virus ( pevb ) with the phytoene desaturase ( pds ) 
 or unifoliata ( uni ) genes . as would be predicted , 

bleaching of leaves was observed with the pds constructs 
 and abnormal flowers with the uni constructs , whereas 
 plants inoculated with a control construct were unaffected .
the nature of molecular recognition specificity was 
 addressed by tom ashfield ( indiana university , bloomington , 
 usa ) through a study of bacterial disease resistance 
 mediated by so - called r - genes .
the rpm1 and rpg1-b 
 genes , from arabidopsis and soybean respectively , confer 
 resistance to pseudomonas syringae strains expressing the 
 effector protein avrb . by comparing their sequences
, ashfield 
 discovered that the genes were not orthologous , 
 implying independent evolution of two functionally equivalent 
 r - alleles ( ' convergent evolution ' ) .
martin crespi ( cnrs , gif - sur - yvette , france ) reported the 
 characterization of the m. truncatula transcriptome during 
 root - growth accompanying adaptation to salt stress , using 
 microarrays , subtractive hybridization libraries ( ssh ) and 
 homology searches .
he has identified 320 genes , of which 
 52 were completely unknown and 72 appear to be legume - specific , 
 suggesting novel pathways linked to environmental 
 stress responses in m. truncatula .
several of these 
 genes are potential regulators , for example , crespi found 11 
 transcription factors .
christine beveridge ( university of queensland , brisbane , 
 australia ) reported the integration of genetic and phenotypic 
 data to test genetic models related to the control of pea bud 
 outgrowth .
one of seven ramosus genes , rms1 , is auxin - responsive 
 and encodes an enzyme of unknown function 
 acting on the pathway for the biosynthesis or metabolism of 
 a long - distance developmental signal involved in the inhibition 
 of bud outgrowth .
moreover , rms1 is regulated by 
 auxin - independent long - distance signal(s ) .
hans weber ( institute for plant genetics and crop plant 
 research , gatersleben , germany ) showed that transgenic 
 legumes that have incorporated metabolic pathway genes - 
 either by expressing a bacterial phosphoenolpyruvate carboxylase 
 gene or by the overexpression of a legume amino - acid 
 transporter gene - have increased seed sink strength 
 ( the ability to accumulate metabolites ) and protein content . 

these results reveal an enormous complexity and flexibility 
 in seed development and metabolism because pleiotropic 
 phenotypes are created even if the expression of a single 
 gene has been altered .
a general conclusion to the conference was given by marc 
 zabeau ( european plant science organisation , ghent , 
 belgium ) who developed the idea that there is an urgent 
 need for a long - term global vision to integrate plant biotechnologies , 
 genomics and agriculture in order to double agricultural 
 productivity by the 2050s .
only an improved 
 understanding of plant biology , coupled with concerted 
 international efforts , will allow us to reach the objective of 
 an economically and environmentally sustainable agriculture . 

 a report on the second international conference on 
 legume genomics and genetics , organized jointly with the 
 fifth aep european conference on grain legumes " legumes 
 for the benefit of agriculture , nutrition and the environment : 
 their genomics , their products and their improvement " , 
 dijon , france , 7 - 11 june 2004 . 
None
Genetics and molecular biology of model and
other legumes
Biotic and abiotic interactions
Plant development and breeding