Fourteen strains were isolated from nitrogen-fixing nodules on the roots of plants of the genus Mimosa growing in Taiwan, Brazil and Venezuela. On the basis of 16S rRNA gene sequence similarities, all of the strains were previously shown to be closely related to each other and to belong to the genus Burkholderia. A polyphasic approach, including DNA-DNA reassociation, whole-cell protein analysi...

The influence of nematodes on nodulation of soybean varied according to their modes of parasitism. In the greenhouse, nodule formation was stimulated by the endoparasites, Meloidogyne hapla and Pratylenchus penetrans, but was inhibited slightly by the ectoparasite, Belonolaimus longicaudatus. In an experiment under controlled conditions in a phytotron, Heterodera glycines severely inhibited nod...

The development of nitrogen fixing root nodules is complex and involves an interplay of signaling processes. During maturation of plant host cells and their endocytosed rhizobia in symbiosomes, host cells and symbiosomes expand. This expansion is accompanied by a large quantity of membrane biogenesis. We recently characterized an AGC kinase gene, MtIRE, that could play a role in this expansion....

The development of nitrogen-fixing nodules is induced on the roots of legume host plants by Rhizobium bacteria. We employed a novel strategy to probe the underlying mechanism of nodule morphogenesis in alfalfa roots using pTZS, a broad host range plasmid carrying a constitutive trans-zeatin secretion (tzs) gene from Agrobacterium tumefaciens T37. This plasmid suppressed the Nod- phenotype of Rh...

Rhizobia elicit nitrogen-fixing nodules on legume roots composed of highly differentiated plant and bacterial cells. Sustaining symbiosis is energy intensive, and an increase in plant and bacterial heme protein synthesis is an essential feature of nod-ule ontogeny. Symbiotic bacteroids express cytochrome heme proteins as part of an electron transport system that allows vigorous and efficient re...

Root nodules are the symbiotic organ of legumes that house nitrogen-fixing bacteria. Many genes are specifically induced in nodules during the interactions between the host plant and symbiotic rhizobia. Information regarding the regulation of expression for most of these genes is lacking. One of the largest gene families expressed in the nodules of the model legume Medicago truncatula is the no...

Morphogenesis of stem nodules in Sesbania rostrata was studied over a period of 6 days after inoculation with an appropriate species of Rhizobium. Nodulation sites were initially slightly raised, circular areas 0.3 to 0.6 mm in diameter and 4 to 5 mm apart in vertical rows along the length of the stem. Each site was underlaid by an adventitious root primordium. A site became susceptible to infe...

Alder (Alnus glutinosa) and more than 200 angiosperms that encompass 24 genera are collectively called actinorhizal plants. These plants form a symbiotic relationship with the nitrogen-fixing actinomycete Frankia strain HFPArI3. The plants provide the bacteria with carbon sources in exchange for fixed nitrogen, but this metabolite exchange in actinorhizal nodules has not been well defined. We i...