Exploring Legume Associations with Fungi and Threat

Kew is investigating the Berlinia group of caesalpinioid legumes which can form mutualistic associations with fungi.

Berlinia congolensis in Gabon. Photo: J. Wieringa

 Legume-rhizobium symbiosis is a textbook example of mutualism. However, it is perhaps less well-known that certain caesalpinioid legumes form mutualistic associations with fungi. Ectomycorrhizal relationships have been reported in the Berlinia group which comprises about 200 tropical African tree species in 18 genera, the majority of which have been a particular focus of study by legume specialists at Kew and Wageningen in recent years.

Some members of this group form monotypic stands in the coastal forests of West and West-Central Africa. Such monotypic stands are considered to be indicators of high quality forest of high conservation value. IUCN conservation assessments are available for few of these tropical African legume giants but several have been formally assessed as threatened with extinction. The fungal symbionts of the Berlinia group species are little known, but where they are species specific they too may be considered threatened.

Both the trees and the fungal symbiont are of economic importance. The trees are often valued for their timber; and the fruitbodies of certain ectomycorrhizal species of Amanita, Cantharellus, Russula and Lactarius consitute an important local food source.

This project, started in 2011, is assembling a data set which will enable documentation of the conservation status of the species of the Berlinia group and, where feasible, their fungal symbionts. Herbarium records and literature search will be the primary approaches in the first instance.

For species for which sufficient data can be collated, a preliminary assessment of the conservation status will be prepared.

Species pages for representative members of the group will also be compiled for web-dissemination, following the model already established at Kew. The data set will enable us to explore patterns of diversity and threat and form the foundation for future research projects on these ecologically important and interesting organisms.