LysM domains of Medicago truncatula NFP protein involved in Nod factor perception. Glycosylation state, molecular modeling and docking of chitooligosaccharides and Nod factors.

The establishment of the symbiosis between legume plants and rhizobial bacteria depends on the production of rhizobial lipo-chitooligosaccharidic signals (the Nod factors) that are specifically recognized by roots of the host plant. In Medicago truncatula, specific recognition of Sinorhizobium meliloti and its Nod factors requires the NFP (Nod factor perception) gene, which encodes a putative serine/threonine receptor-like kinase (RLK). The extracellular region of this protein contains three tandem lysin motifs (LysMs), a short peptide domain that is implicated in peptidoglycan or chitin binding in various bacterial or eukaryotic proteins, respectively.

Genetics of symbiosis in Lotus japonicus: recombinant inbred lines, comparative genetic maps, and map position of 35 symbiotic loci.

Development of molecular tools for the analysis of the plant genetic contribution to rhizobial and mycorrhizal symbiosis has provided major advances in our understanding of plant-microbe interactions, and several key symbiotic genes have been identified and characterized. In order to increase the efficiency of genetic analysis in the model legume Lotus japonicus, we present here a selection of improved genetic tools. The two genetic linkage maps previously developed from an interspecific cross between L.

Seven Lotus japonicus genes required for transcriptional reprogramming of the root during fungal and bacterial symbiosis.

A combined genetic and transcriptome analysis was performed to study the molecular basis of the arbuscular mycorrhiza (AM) symbiosis. By testing the AM phenotype of nodulation-impaired mutants and complementation analysis, we defined seven Lotus japonicus common symbiosis genes (SYMRK, CASTOR, POLLUX, SYM3, SYM6, SYM15, and SYM24) that are required for both fungal and bacterial entry into root epidermal or cortical cells. To describe the phenotype of these mutants at the molecular level, we screened for differentiating transcriptional responses of mutant and wild-type roots by large-scale gene expression profiling using cDNA-amplified fragment length polymorphism.

Plastid proteins crucial for symbiotic fungal and bacterial entry into plant roots.

The roots of most higher plants form arbuscular mycorrhiza, an ancient, phosphate-acquiring symbiosis with fungi, whereas only four related plant orders are able to engage in the evolutionary younger nitrogen-fixing root-nodule symbiosis with bacteria. Plant symbioses with bacteria and fungi require a set of common signal transduction components that redirect root cell development. Here we present two highly homologous genes from Lotus japonicus, CASTOR and POLLUX, that are indispensable for microbial admission into plant cells and act upstream of intracellular calcium spiking, one of the earliest plant responses to symbiotic stimulation.

A plant receptor-like kinase required for both bacterial and fungal symbiosis.

Most higher plant species can enter a root symbiosis with arbuscular mycorrhizal fungi, in which plant carbon is traded for fungal phosphate. This is an ancient symbiosis, which has been detected in fossils of early land plants. In contrast, the nitrogen-fixing root nodule symbioses of plants with bacteria evolved more recently, and are phylogenetically restricted to the rosid I clade of plants.

Dual requirement of the LjSym4 gene for mycorrhizal development in epidermal and cortical cells of Lotus japonicus roots.

• The LjSym4 mutation leads to Lotus japonicus plants that are defective in arbuscular mycorrhiza (AM) development. • Two alleles of LjSym4 with different phenotypic strength are compared here. The development of AM was assessed by considering five parameters related to fungal structures present in root segments from wild-type and mutant plants.

A tomato cysteine protease required for Cf-2-dependent disease resistance and suppression of autonecrosis.

Little is known of how plant disease resistance (R) proteins recognize pathogens and activate plant defenses. Rcr3 is specifically required for the function of Cf-2, a Lycopersicon pimpinellifolium gene bred into cultivated tomato (Lycopersicon esculentum) for resistance to Cladosporium fulvum. Rcr3 encodes a secreted papain-like cysteine endoprotease.