Nodulation is the quantitatively predominant insect cellular immune function activated in response to bacterial, fungal and some viral infections. We posed the hypothesis that parasitoid insects express melanotic nodulation reactions to viral challenge and that eicosanoids mediate these reactions. Treating fifth-instar larvae of the ichneumonid endoparasitoid Pimpla turionellae with Bovine Herp...

We have identified two Rhizobium meliloti genes (nodD2 and nodD3) that are highly homologous and closely linked to the regulatory gene nodD (nodD1). R. meliloti strains containing mutations in the three nodD genes in all possible combinations were constructed and their nodulation phenotypes were assayed on Medicago sativa (alfalfa) and Melilotus alba (sweet clover). A triple nodD1-nodD2-nodD3 m...

abstract plants are exposed to stressful environmental conditions in the process of growth and development. one of the most important stresses is the salt stress which can limit the plant’s growth and yield. plants symbiosis with arbuscular mycorrhizal fungi in salt conditions can affect the plant’s yield as well as growth parameters. the plant’s growth in salt stressful conditions might be red...

Parasponia, a woody member of the elm family, is the only nonlegume genus whose members are known to form an effective nitrogen-fixing symbiosis with Bradyrhizobium or Rhizobium species. The Bradyrhizobium strain Rp501, isolated from Parasponia nodules, also nodulates the legumes siratro (Macroptilium atropurpureum) and cowpea (Vigna unguiculata). To test whether some of the same genes are invo...

Upon submergence, Azorhizobium caulinodans infects the semiaquatic legume Sesbania rostrata via the intercellular crack entry process, resulting in lateral root-based nodules. A gene encoding a gibberellin (GA) 20-oxidase, SrGA20ox1, involved in GA biosynthesis, was transiently up-regulated during lateral root base nodulation. Two SrGA20ox1 expression patterns were identified, one related to in...

Many studies demonstrate that elevated atmospheric carbon dioxide concentrations (eCO2) can promote root nodulation and biological nitrogen fixation (BNF) in legumes such as lucerne (Medicago sativa). But when elevated temperature (eT) conditions are applied in tandem with eCO2, a more realistic scenario for future climate change, the positive effects of eCO2 on nodulation and BNF in M. sativa ...

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 availability of soybean mutants with altered symbiotic properties allowed an investigation of the shoot or root control of the relevant phenotype. By means of grafts between these mutants and wild-type plants (cultivar Bragg and Williams), we demonstrated that supernodulation as well as hypernodulation (nitrate tolerance in nodulation and lack of autoregulation) is shoot controlled in two m...

The exogenous addition of salicylic acid (SA) was previously shown to inhibit indeterminate but not determinate-type nodulation. We sought to extend these results by modulating endogenous levels of SA through the transgenic expression of salicylate hydroxylase (NahG) in both stably transformed Lotus japonicus and composite Medicago truncatula plants. NahG expression in L. japonicus resulted in ...

Many studies have documented the involvement of eicosanoids in insect cellular immune responses to bacteria. The use of the fungal pathogen Beauveria bassiana as a nodulation elicitor, with inhibition of phospholipase A(2) by dexamethasone, extends the principle to fungi. This study also provides the first evidence of involvement of the lipoxygenase (LOX) pathway rather than the cyclooxygenase ...