Cloning of four chitinase genes and a lectin gene in Galega orientalis

Abstract

The legume goat's rue (Galega orientalis) and its microsymbiont Rhizobium galegae have an unusually strict host-bacteria specificity. The reason for this is not known. We have identified and analysed six genes in G. orientalis assumed to be involved in the recognition processes between legumes and rhizobia. The genes were isolated from a library made from nodulating roots. The genes were identified by sequence analysis as class la, Ib and class IV chitinases, a lectin, and a presumptive defensin. The chitinase and lectin sequences were used to complete phylogenetic trees. In the phylogenetic tree, the G. orientalis lectin gene is placed in the same group as Pisum sativum Nlec, Blec and Robinia pseudoacacia LEC3. These genes have been suggested to be involved in different developmental processes. Defensins are involved in several defence functions, and recently there have been a few publications on defensins involved in nodulation. 2 The activity of chitinases in different tissues and in nodulated roots was investigated by western blots and activity gels. G. orientalis has at least four different active chitinases. The sequences described in the article have the following GenBank accession codes: AY253984, AY253985, AY253986, AY253987, AY253988, AY333428