The importance of sexual recombination in determining fungal population structure cannot be inferred solely from the relative abundance of sexual and asexual spores and reproductive structures. To complement a previously reported study of proportions of Mycosphaerella graminicola ascocarps and pycnidia, we investigated the share of sexual recombinants among isolates randomly derived from the sa...

The Brazilian inoculant strains 29W and 587 were found to be members of Bradyrhizobium elkanii primarily on the basis of 16S rRNA gene sequences identical to that of B. elkanii USDA76 and on the basis of reactivity with antibodies against serogroups 76 and 31, respectively. The agronomic consequences of using strains of B. elkanii as soybean inoculants are discussed.

An immunoblot procedure for the strain-specific quantitative analysis of commercial Rhizobium inoculants was developed. The technique greatly reduced the time required for inoculant analysis. Correlation between immunoblot analysis and traditional plant nodule grow-out most-probable-number techniques was r = 0.90 for 16 commercial alfalfa inoculants tested.

Rhizobia are soil-borne bacteria that form nodules with legume roots and convert nitrogen into ammonia. Legume plants are often a major part of native or agricultural ecosystems, which increas nitrogen in low fertility soils, e.g. saline soils. The major target of this study was to characterize salt-tolerant rhizobial strains with high symbiotic efficiency. We choose ten strains of rhizobia tha...

Rhizobial symbionts were isolated from the surface (0–0.5 M) and phreatic (3.9–5.0 M) root environments of a mature mesquite woodland in the Sonoran Desert of Southern California, and from variable depths (0–12 m) of non-phreatic mesquite ecosystems in the Chihuahuan Desert of New Mexico. They were tested for their ability to tolerate high salinity, and respire NO3 2 as mechanisms of free-livin...

The symbiotic effectiveness and nodulation competitiveness of Rhizobium leguminosarum bv. trifolii soil isolates were evaluated under nonsoil greenhouse conditions. The isolates which we used represented both major and minor nodule-occupying chromosomal types (electrophoretic types [ETs]) recovered from field-grown subclover (Trifolium subterraneum L.). Isolates representing four ETs (ETs 2, 3,...

BACKGROUND AND OBJECTIVES Interactions between plants and beneficial soil organisms (e.g. rhizobial bacteria, mycorrhizal fungi) are models for investigating the ecological impacts of such associations in plant communities, and the evolution and maintenance of variation in mutualisms (e.g. host specificity and the level of benefits provided). With relatively few exceptions, variation in symbiot...