Nodulation ability of 15 Rhizobium strains isolated from root and stem nodules of tropical Aeschynomene species was studied on 20 different Aeschynomene species and four other legumes-Arachis hypogaea, Stylosanthes guianensis, Macroptilium atropurpureum, and Sesbania rostrata. The results of this investigation showed that Aeschynomene species could be divided into three groups according to the ...

Nodulations of Glycine max L. seedlings by parental Rhizobium japonicum (USDA strain 26) and a tryptophan catabolic mutant (tan 4b, NRRL strain B-14075) were evaluated for effectiveness. Seedlings grown in plastic pouches were compared based on increases in root weight (wt.), nodule volume (vol.) and acetylene-reducing (AR) activity. The tan 4b mutant, which can produce extracellular indol-3yl-...

Using a plate induction assay, we demonstrate that alfalfa exudes inducer of Rhizobium meliloti nodulation genes. The inducer is exuded from the infectible zone of the root, accumulates to at least 1 micromolar, and is not affected by 10 millimolar nitrate. No zones of inhibition are observed. A nodulation minus mutant line of alfalfa, MN-1008, exudes normal levels of inducer. R. meliloti grown...

Nodulation, nodule development and senescence directly affects nitrogen fixation efficiency, and previous studies have shown that inhibition of some cysteine proteases delay nodule senescence, so their nature inhibitors, cystatin genes, are very important in nodulation, nodule development, and senescence. Although several cystatins are actively transcribed in soybean nodules, their exact roles ...

Abstract: Soybean develop new root organs that become nitrogen-fixing nodules in response to signals from rhizobacteria and then use complex systemic signalling to control cell proliferation. Recent application of functional genomics resulted in the characterization of genes encoding Leucine rich repeat (LRR) receptor kinases controlling these early nodulation steps. With short and long distanc...

SUMMARY Rhizobium lipochitooligosaccharide signal molecules stimulate multiple responses in legume host plants, including changes in host gene expression, cell growth, and mitoses leading to root nodule development. The basis for signal transduction in the plant is not known. We examined cytoplasmic free calcium in host root hairs using calcium-sensitive reporter dyes. Image analysis of injecte...

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...

CLE (CLAVATA3/Embryo Surrounding Region) peptides regulate different aspects of plant development. In legumes, are known as key components autoregulation nodulation (AON), which systemically controls the number nitrogen-fixing nodules formed on root upon symbiotic interaction with soil bacteria rhizobia. produced in response to rhizobia inoculation and transported via xylem shoot, where they re...

The sym 5 mutants of pea, Pisum sativum L. cv Sparkle, do not differ in growth habit from their normal parent and nodulate poorly at a root temperature of 20 degrees C. If inhibitors of ethylene formation or action (Co(2+), aminoethoxyvinylglycine, or Ag(+)) are added to the substrate, nodulation of the sym 5 mutants is increased. Similar treatments of four other mutant sym lines do not restore...