Classical and Molecular Genetics of the Model Legume <i>Lotus japonicus</i>

Jiang, Qunyi; Gresshoff, Peter M.

doi:10.1094/mpmi.1997.10.1.59

Cited by 115 publications

(59 citation statements)

References 26 publications

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“…nup85-1 (Ljsym24), nup85-2 (Ljsym73), and nup85-3 (Ljsym85) are alleles affecting AM and nodule symbioses in mutants isolated from ethyl methanesulfonatemutagenized L. japonicus B-129 (Szczyglowski et al, 1998;Kawaguchi et al, 2002Kawaguchi et al, , 2005Sandal et al, 2006). For allelism test, plants were crossed reciprocally according to Jiang and Gresshoff (1997). A possible allelic mutant, B46-D (Murray et al, 2006), is assigned as nup85-4.…”

Section: Biological Materialsmentioning

confidence: 99%

NUCLEOPORIN85 Is Required for Calcium Spiking, Fungal and Bacterial Symbioses, and Seed Production in Lotus japonicus

et al. 2007

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In Lotus japonicus, seven genetic loci have been identified thus far as components of a common symbiosis (Sym) pathway shared by rhizobia and arbuscular mycorrhizal fungi. We characterized the nup85 mutants (nup85-1, -2, and -3) required for both symbioses and cloned the corresponding gene. When inoculated with Glomus intraradices, the hyphae managed to enter between epidermal cells, but they were unable to penetrate the cortical cell layer. The nup85-2 mutation conferred a weak and temperature-sensitive symbiotic phenotype, which resulted in low arbuscule formation at 228C but allowed significantly higher arbuscule formation in plant cortical cells at 188C. On the other hand, the nup85 mutants either did not form nodules or formed few nodules. When treated with Nod factor of Mesorhizobium loti, nup85 roots showed a high degree of root hair branching but failed to induce calcium spiking. In seedlings grown under uninoculated conditions supplied with nitrate, nup85 did not arrest plant growth but significantly reduced seed production. NUP85 encodes a putative nucleoporin with extensive similarity to vertebrate NUP85. Together with symbiotic nucleoporin NUP133, L. japonicus NUP85 might be part of a specific nuclear pore subcomplex that is crucial for fungal and rhizobial colonization and seed production.

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Section: Biological Materialsmentioning

confidence: 99%

NUCLEOPORIN85 Is Required for Calcium Spiking, Fungal and Bacterial Symbioses, and Seed Production in Lotus japonicus

et al. 2007

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“…Crossing the L. japonicus homozygous mutant lines with the wild-type Gifu parental line was performed using a manual emasculation and pollination procedure as described previously (Jiang and Gresshoff, 1997). Root hair and symbiotic characteristics of the resulting F 1 and F 2 generations were scored and used to determine the genetic basis of the observed phenotypes.…”

Section: Complementation and Genetic Segregation Analysesmentioning

confidence: 99%

Invasion of Lotus japonicus root hairless 1 by Mesorhizobium loti Involves the Nodulation Factor-Dependent Induction of Root Hairs

et al. 2005

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In many legumes, including Lotus japonicus and Medicago truncatula, susceptible root hairs are the primary sites for the initial signal perception and physical contact between the host plant and the compatible nitrogen-fixing bacteria that leads to the initiation of root invasion and nodule organogenesis. However, diverse mechanisms of nodulation have been described in a variety of legume species that do not rely on root hairs. To clarify the significance of root hairs during the L. japonicusMesorhizobium loti symbiosis, we have isolated and performed a detailed analysis of four independent L. japonicus root hair developmental mutants. We show that although important for the efficient colonization of roots, the presence of wild-type root hairs is not required for the initiation of nodule primordia (NP) organogenesis and the colonization of the nodule structures. In the genetic background of the L. japonicus root hairless 1 mutant, the nodulation factor-dependent formation of NP provides the structural basis for alternative modes of invasion by M. loti. Surprisingly, one mode of root colonization involves nodulation factor-dependent induction of NP-associated cortical root hairs and epidermal root hairs, which, in turn, support bacterial invasion. In addition, entry of M. loti through cracks at the cortical surface of the NP is described. These novel mechanisms of nodule colonization by M. loti explain the fully functional, albeit significantly delayed, nodulation phenotype of the L. japonicus ROOT HAIRLESS mutant.

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“…Both species possess small genomes, are diploid, have fast generation times, and can be transformed with Agrobacterium tumefaciens and regenerated (Handberg and Stougaard, 1992; Blondon et al, 1994;Handberg et al, 1994; Chabaud et al, 1996;Jiang and Gresshoff, 1997;Stiller et al, 1997;Trinh et al, 1998;Trieu et al, 2000). Currently, both functional and structural genomics approaches are being pursued within each of these species.…”

mentioning

confidence: 99%

Genome-Wide Identification of Nodule-Specific Transcripts in the Model Legume Medicago truncatula

et al. 2002

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The Medicago truncatula expressed sequence tag (EST) database (Gene Index) contains over 140,000 sequences from 30 cDNA libraries. This resource offers the possibility of identifying previously uncharacterized genes and assessing the frequency and tissue specificity of their expression in silico. Because M. truncatula forms symbiotic root nodules, unlike Arabidopsis, this is a particularly important approach in investigating genes specific to nodule development and function in legumes. Our analyses have revealed 340 putative gene products, or tentative consensus sequences (TCs), expressed solely in root nodules. These TCs were represented by two to 379 ESTs. Of these TCs, 3% appear to encode novel proteins, 57% encode proteins with a weak similarity to the GenBank accessions, and 40% encode proteins with strong similarity to the known proteins. Nodule-specific TCs were grouped into nine categories based on the predicted function of their protein products. Besides previously characterized nodulins, other examples of highly abundant nodule-specific transcripts include plantacyanin, agglutinin, embryo-specific protein, and purine permease. Six nodule-specific TCs encode calmodulin-like proteins that possess a unique cleavable transit sequence potentially targeting the protein into the peribacteroid space. Surprisingly, 114 nodule-specific TCs encode small Cys cluster proteins with a cleavable transit peptide. To determine the validity of the in silico analysis, expression of 91 putative nodule-specific TCs was analyzed by macroarray and RNA-blot hybridizations. Nodule-enhanced expression was confirmed experimentally for the TCs composed of five or more ESTs, whereas the results for those TCs containing fewer ESTs were variable. , and organ development (Ruan et al., 1998;Girke et al., 2000; Zhu and Wang, 2000). Although Arabidopsis serves as the model system for most plant processes, it suffers from two major weaknesses in consideration of plant-microbe interactions: the absence of symbiotic associations with mycorrhizal fungi and with rhizobia.In recent years, Medicago truncatula and Lotus japonicus have emerged as model systems for genomic approaches to plant-microbe symbiotic associations (Barker et al., 1990;Handberg and Stougaard, 1992; Cook et al., 1997; Cook, 1999;Oldroyd and Geurts, 2001;Thoquet et al., 2002). Both species possess small genomes, are diploid, have fast generation times, and can be transformed with Agrobacterium tumefaciens and regenerated (Handberg and Stougaard, 1992; Blondon et al., 1994;Handberg et al., 1994; Chabaud et al., 1996;Jiang and Gresshoff, 1997;Stiller et al., 1997;Trinh et al., 1998;Trieu et al., 2000). Currently, both functional and structural genomics approaches are being pursued within each of these species. Covitz et al. (1998) reported the sequencing of about 900 cDNA tags from the M. truncatula root hairs. In addition, hundreds more expressed sequence tags (ESTs) have been isolated and characterized from effective root nodules of L. japonicus and M. truncatula, and a ...

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Classical and Molecular Genetics of the Model Legume Lotus japonicus

Cited by 115 publications

References 26 publications

NUCLEOPORIN85 Is Required for Calcium Spiking, Fungal and Bacterial Symbioses, and Seed Production in Lotus japonicus

NUCLEOPORIN85 Is Required for Calcium Spiking, Fungal and Bacterial Symbioses, and Seed Production in Lotus japonicus

Invasion of Lotus japonicus root hairless 1 by Mesorhizobium loti Involves the Nodulation Factor-Dependent Induction of Root Hairs

Genome-Wide Identification of Nodule-Specific Transcripts in the Model Legume Medicago truncatula

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