ARS | Publication request: The Mycorrhizal Status of Pseudotulostoma Volvata (Elaphomycetaceae, Eurotiales, Ascomycota).

Submitted to: Mycorrhiza
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 11, 2006
Publication Date: May 17, 2006
Citation: Henkel, T.W., James, T.Y., Miller, S.L., Aime, M.C., Miller, Jr., O.K. 2006. The mycorrhizal status of Pseudotulostoma volvata (Elaphomycetaceae, Eurotiales, Ascomycota). Mycorrhiza 16(3):241-244.

Interpretive Summary: Fungi are essential for the growth of nearly all land plants and are important in regions where nutrients are scarce. This required association of fungi with the roots of trees and crop plants is called mycorrhiza for myco = fungus and rhiza = root. Determining whether or not a fungus is mycorrhizal with a plant is not easy, yet this knowledge is essential for efficient management of forests, crops, and reforestation efforts. A recently described fungus in the Eurotiales, a large group that includes those fungi that produce the antibiotic penicillin, occurs in a tropical forest in Guyana. The nutritional status of this fungus was unknown despite evidence that suggested that it was mycorrhizal with the dominant tree species, a large legume related to dry beans and other important crop plants. By digging beneath the fruiting bodies of the fungus it was possible to observe that parts of the fungus were connected with the tree roots. In addition, the tree roots were modified in their appearance due to their association with the fungus. Finally, DNA was extracted from the tree roots and then sequenced to determine the identity of the fungus associated with the roots. Based on these observations it is conclusively established that the fungus is mycorrhizal with the dominant tropical forest tree in this area of Guyana. Significantly, this is the first known association of a fungus from the Eurotiales forming a mycorrhizal symbiosis with any species of legume. This is also the first report of a mycorrhizal eurotialian fungus in tropical South America. This research will be used by foresters and land-use managers to determine the best methods for preserving tropical forest tree diversity and understanding the essential relationship between fungi and plants.

Technical Abstract: Pseudotulostoma volvata O.K. Mill. & T.W. Henkel is a morphologically unusual member of the otherwise hypogeous Elaphomycetaceae due to its epigeous habit and exposed gleba borne on an elevated stalk at maturity. Field observations in Guyana indicated that P. volvata is restricted to rain forests dominated by ectomycorrhizal (EM) Dicymbe corymbosa (Caesalpiniaceae), suggesting an EM nutritional mode for the fungus. An EM status for P. volvata would corroborate its placement in the ectotrophic Elaphomycetaceae. Here we confirm the EM status of P. volvata using a combination of morphological, molecular, and mycosociological data.