Relationships Amongst the Fast‐growing Rhizobia of Lablab purpureus, Leucaena leucocephala, Mimosa spp., Acacia farnesiana and Sesbania grandiflora and their Affinities with Other Rhizobial Groups

Abstract

M . J. TRINICK This paper reports on the infective ability, morphology, colony characteristics, growth in litmus milk, precipitation in calcium glycerophosphate medium, carbohydrate utilization and serology of fast-growing rhizobia from the tropical legumes M . inoisa, M . pudicu, A . farnesiuna, S. grundijora, Lublub purpureus and Leucuenu Ieucocephula. The relationship of this group to other established host groups is examined. Materials and Methods PIunt hostsLeucuenu leucocephala (Lam.) de Wit., Mimosa incisa Mart., M . pudica L., Acacia furnesiana (L.) Willd. and Seshaniu grand$ora Poir. are nodulated only with fastgrowing root-nodule bacteria. Only one fast-growing nodule symbiont was isolated from Lublub purpureus (L.) Sweet which is usually nodulated, like other tropical legumes, with slow-growing types. These hosts will be referred to by their generic name throughout the text and M . incisu is the test species of Mimosa when not otherwise specified. Other tropical legumes are listed in Tables 1, 2 and 3 and were nodulated in the field only by slow-growing rhizobia. Source of Rhizobium struinsThe NGR prefix indicates a source in Papua New Guinea. The fast-growing rootnodule bacteria from Leucuenu and Mimosa spp. were isolated from nodulated plants growing in slightly acid (pH 5 5 ) , neutral and alkaline soils (pH 8.3) in Papua New Guinea. Only one isolate from Acacia and two from Seshania growing in alkaline soils were used in this study. The isolate, NGR 234, from Lahlab was the only fast-growing isolate obtained from 30 nodules collected from plants growing in a soil with pH 8.5. The other 29 isolates were slow-growing. The fast-growing isolates were shown to be free from associated slow-growing rhizobia by their repeated streaking for isolated colonies on yeast-extract mannitol medium (YMA) containing brom thyniol blue after shaking in water for 10 min and after growth in broth culture: also only fast-growers were re-isolated from nodulated plants inoculated with low rhizobial populations (1 to 10 cells). The slow-growing strains of Rhizobium were isolated from tropical legumes and the non-legume Parusponia andersonii (Trinick 1980) grown in similar locations in Papua New Guinea. All strains of Rhizobium were isolated on YMA and were preserved by lyophilization. Characterization of the, fust-growing rhizobirr Staining and morphology old cultures grown on YMA at 27°C. Cultures were examined for motility, cell morphology and Gram reaction on2 and 3 d Colony characteristics colonies of R. meliloti and cowpea-type strains. Characteristics of 7 and 10 d old isolated colonies on YMA were compared with

Cross inoculation studies: Response of Vigna mungo to inoculation with rhizobia from tree legumes growing under arid Environment

“…There have been reports of alkali producing Rhizobium strains (Hernandez and Focht, 1984) and acid producing Bradyrhizobium strains (Moerira, et al, 1993;Padmanabhan, et al, 1990). Legume trees are infected as much by fast growing rhizobia as by slow growing rhizobia (Moerira, et al, 1998;Trinick, 1980;Turk and Keyser, 1992;Zhang, et al, 1991). Some tree rhizobial strains are host specific, whereas others have a wide host range (Dommergues, , 1984).…”

Numerical Taxonomy of Rhizobium Strains from Legumes of the Temperate Zone

“…Georgia (17) Georgia (17) Ukraine (this work) Ukraine (this work) Ukraine (this work) Colombia (16) 2 China (34) New Guinea (27) China (3) Finland (13) Estonia (17) 2 20 Kazakhstan (17) Latvia (17) Australia (8) ity. In all plant tests, uninoculated plants were included as controls.…”

Bradyrhizobium lablabi sp. nov., isolated from effective nodules of Lablab purpureus and Arachis hypogaea

“…In these areas, the seeds and immature pods are used for human consumption while the herbage is used as a green manure (Murphy & Colucci, 1999). To date, only a few rhizobial strains isolated from L. purpureus nodules have been studied and most of these have been identified as members of the genus Bradyrhizobium (Morrison et al, 1986), except for the broad host range strain NGR 234 (Trinick, 1980). total of 93) were characterized and classified in the genus Bradyrhizobium based on 16S rRNA gene RFLP, 16S-23S rRNA intergenic spacer (IGS) RFLP and sequence analyses of rrs, IGS, atpD, recA, nodC and nifH genes (unpublished data).…”