Isolation of Frankia from nodules of Trevoa trinervis: ultrastructural characterization

Abstract

CARRASCO, A., SCHWENCKE, J., and CARU, M. 1992. Isolation of Frankia from nodules of Trevoa trinervis: ultrastructural characterization. Can. J. Microbiol. 38: 174-180. Root nodules obtained from Trevoa trinervis and its actinomycete Frankia were studied by electron microscopy. The microsymbiont was found in the cortical cells and it exhibits the typical actinomycetal structures: septate hyphae and symbiotic vesicles. Using the double-layer technique, two Frankia strains were isolated from the nodules. In vitro these strains exhibit morphological characteristics considered specific to the genus Frankia, i.e., hyphae, Frankia vesicles, and polymorphic sporangia. CARRASCO, A., SCHWENCKE, J., et CARU, M. 1992. Isolation of Frankia from nodules of Trevoa trinervis: ultrastructural characterization. Can. J. Microbiol. 38 : 174-1 80. Les nodules radiculaires obtenu de Trevoa trinervis et son actinomycete Frankia ont Ct C CtudiCes par microscopie Clectronique. Le microsymbiote Ctait trouvC dans les cellules corticales et on exhibe le plus typique actinomycetal structures : des hyphes et des vesicules symbiotiques. En utilisant la technique de double-plaque, on a is016 deux souches d'actinomyckte a partir des nodules. Des souches sont considerkes comme appartenant au genre Frankia puisqu'elles posskdent les caractkres morphologiques propres a ce genre : des Frankia hyphes, des vCsicules et des sporanges polymorphes.

Studies of two Frankia strains isolated from Trevoa trinervis Miers

“…The results indicate that both Frankia strains have the ability to infect and nodulate the original host, the percentage of infection being of 95% for TtI 11, and 100% for the TtI 12 isolate. The nodules induced on T. trinervis Miers root systems were of the same external morphology described in a previous article (Carrasco et al, 1992), i.e. clusters of coralloid root nodules with a dichotomous branching pattern.…”

“…Bacterial strains Frankia sp TtI 11 and TtI 12, isolated from the root nodules of T. trinervis Miers as described previously (Carrasco et al, 1992) were used in this study. Strain BR, isolated from Casuarina equisetifolia and provided by Dr H G Diem was used as standard (unpublished).…”

“…We have previously reported the isolation of Frankia strains TtI 11 and TtI 12 from T. trinervis Miers nodules (Carrasco et al, 1992). Recently, Caru (1993) reported the isolation of another Frankia strain from the same actinorhinal host.…”

“…Both the nodules induced by Frankia and the species of plants which bear these nodules are termed actinorhizal (Tjepkema and Torrey, 1979). Seven genera ( Colleta, Trevoa, Retanilla, Talguenea, Kentrothamnus, Ceanothus and Discaria) in the family Rhamnaceae have been reported to bear actinorhizal nodules (Balboa et al, 1988;Balboa, 1989;Carrasco et al, 1992;Caru, 1993;Longeri and Abarzua, 1989;Medan and Tortosa, 1976;Medan and Tortosa, 1981;Silvester et al, 1985) Members of the genus Trevoa are restricted to the Pacific coast of South America, with five species in Chile and one in Peru (Navas, 1976). Trevoa trinervis Miers is widespread in the matorral zone of central Chile, being characterized by its fast growth on disturbed sites (primary colonizer) and for its nitrogenfixing capacity, adding nitrogen to the soil (Rundel and Neel, 1978;Silvester et al, 1985).…”

Characterization of native Frankia strains isolated from chilean shrubs (Rhamnaceae)

“…Recently native Frankia strains were isolated from chilean Rhamnaceae shrubs, such as Dis- caria (Abarztia and Longeri 1988;Longeri and Abarztia, 1989), Retanilla (Longeri and Abarztia 1989), Colletia (Carti et al, 1990) and Trevoa (Carrasco et al, 1992). These Frankia strains have been characterized only by their morphological features, this is because of the initial difficulties associated in their isolation, slow growth rate and unidentified nutritional requirements.…”