Large-scale insertional mutagenesis using the Tnt1 retrotransposon in the model legume Medicago truncatula

To gain insight into genomic relationships between soybean (Glycine max) and Medicago truncatula, eight groups of bacterial artificial chromosome (BAC) contigs, together spanning 2.60 million base pairs (Mb) in G. max and 1.56 Mb in M. truncatula, were compared through high-resolution physical mapping combined with sequence and hybridization analysis of low-copy BAC ends. Cross-hybridization among G. max and M. truncatula contigs uncovered microsynteny in six of the contig groups and extensive microsynteny in three. Between G. max homoeologous (within genome duplicate) contigs, 85% of coding and 75% of noncoding sequences were conserved at the level of cross-hybridization. By contrast, only 29% of sequences were conserved between G. max and M. truncatula, and some kilobase-scale rearrangements were also observed. Detailed restriction maps were constructed for 11 contigs from the three highly microsyntenic groups, and these maps suggested that sequence order was highly conserved between G. max duplicates and generally conserved between G. max and M. truncatula. One instance of homoeologous BAC contigs in M. truncatula was also observed and examined in detail. A sequence similarity search against the Arabidopsis thaliana genome sequence identified up to three microsyntenic regions in A. thaliana for each of two of the legume BAC contig groups. Together, these results confirm previous predictions of one recent genome-wide duplication in G. max and suggest that M. truncatula also experienced ancient large-scale genome duplications.Key words: Glycine max, Medicago truncatula, Arabidopsis thaliana, conserved microsynteny, genome duplication.

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An improved genome release (version Mt4.0) for the model legume Medicago truncatula

BMC Genomics ◽

10.1186/1471-2164-15-312 ◽

2014 ◽

Vol 15 (1) ◽

pp. 312 ◽

Cited By ~ 191

Author(s):

Haibao Tang ◽

Vivek Krishnakumar ◽

Shelby Bidwell ◽

Benjamin Rosen ◽

Agnes Chan ◽

...

Keyword(s):

Medicago Truncatula ◽

Model Legume

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Guidelines for Genetic Nomenclature and Community Governance for the Model Legume Medicago truncatula

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2001.14.12.1364 ◽

2001 ◽

Vol 14 (12) ◽

pp. 1364-1367 ◽

Cited By ~ 14

Author(s):

Kathryn A. VandenBosch ◽

Julia Frugoli

Keyword(s):

Medicago Truncatula ◽

Rapid Growth ◽

Model System ◽

Gene Nomenclature ◽

Community Governance ◽

Model Legume ◽

The Past ◽

Genetic Nomenclature ◽

International Collaborations

At the 2nd Medicago meeting (a satellite of the 1999 IS-MPMI meeting in Amsterdam), investigators perceived a need for standardization of genetic nomenclature in Medicago truncatula, due to the rapid growth of research on this species in the past few years. Establishment of such standards grew out of discussions begun at this meeting and continued electronically throughout the M. truncatula community. The proposed standards presented here are the consensus results of those discussions. In addition to standards for gene nomenclature, a method for community governance and a website for cataloging gene names and submitting new ones are presented. The purpose of implementing these guidelines is to help maintain consistency in the literature, to avoid redundancy, to contribute to the accuracy of databases, and, in general, to aid the international collaborations that have made M. truncatula a model system for legume biology.

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Structure and antimicrobial activity of NCR169, a nodule-specific cysteine-rich peptide of Medicago truncatula

Scientific Reports ◽

10.1038/s41598-021-89485-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Noriyoshi Isozumi ◽

Yuya Masubuchi ◽

Tomohiro Imamura ◽

Masashi Mori ◽

Hironori Koga ◽

...

Keyword(s):

Antimicrobial Activity ◽

Medicago Truncatula ◽

Mechanism Of Action ◽

Disulfide Bonds ◽

Sinorhizobium Meliloti ◽

Bound State ◽

Disulfide Linkage ◽

Model Legume ◽

Nmr Structures ◽

And Function

AbstractA model legume, Medicago truncatula, has over 600 nodule-specific cysteine-rich (NCR) peptides required for symbiosis with rhizobia. Among them, NCR169, an essential factor for establishing symbiosis, has four cysteine residues that are indispensable for its function. However, knowledge of NCR169 structure and mechanism of action is still lacking. In this study, we solved two NMR structures of NCR169 caused by different disulfide linkage patterns. We show that both structures have a consensus C-terminal β-sheet attached to an extended N-terminal region with dissimilar features; one moves widely, whereas the other is relatively stapled. We further revealed that the disulfide bonds of NCR169 contribute to its structural stability and solubility. Regarding the function, one of the NCR169 oxidized forms could bind to negatively charged bacterial phospholipids. Furthermore, the positively charged lysine-rich region of NCR169 may be responsible for its antimicrobial activity against Escherichia coli and Sinorhizobium meliloti. This active region was disordered even in the phospholipid bound state, suggesting that the disordered conformation of this region is key to its function. Morphological observations suggested the mechanism of action of NCR169 on bacteria. The present study on NCR169 provides new insights into the structure and function of NCR peptides.

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A method for the isolation of root hairs from the model legume Medicago truncatula

Journal of Experimental Botany ◽

10.1093/jxb/erg245 ◽

2003 ◽

Vol 54 (391) ◽

pp. 2245-2250 ◽

Cited By ~ 12

Author(s):

J. Ramos

Keyword(s):

Medicago Truncatula ◽

Root Hairs ◽

Model Legume

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Insight into the molecular requirements for pathogenicity of Fusarium oxysporum f. sp. lycopersici through large-scale insertional mutagenesis

Genome Biology ◽

10.1186/gb-2009-10-1-r4 ◽

2009 ◽

Vol 10 (1) ◽

pp. R4 ◽

Cited By ~ 87

Author(s):

Caroline B Michielse ◽

Ringo van Wijk ◽

Linda Reijnen ◽

Ben JC Cornelissen ◽

Martijn Rep

Keyword(s):

Fusarium Oxysporum ◽

Large Scale ◽

Insertional Mutagenesis ◽

Insight Into

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Functional specialization of Arf paralogs in nodules of model legume, Medicago truncatula

Plant Growth Regulation ◽

10.1007/s10725-016-0227-2 ◽

2016 ◽

Vol 81 (3) ◽

pp. 501-510 ◽

Cited By ~ 1

Author(s):

Elif Yüzbaşıoğlu ◽

Eda Dalyan ◽

Abdülrezzak Memon ◽

Gül Öz ◽

Bayram Yüksel

Keyword(s):

Medicago Truncatula ◽

Functional Specialization ◽

Model Legume

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Comparison of nodule endophyte composition, diversity, and gene content between Medicago truncatula genotypes

Phytobiomes Journal ◽

10.1094/pbiomes-10-20-0077-r ◽

2021 ◽

Author(s):

Mannix Burns ◽

Brendan Epstein ◽

Liana Burghardt

Keyword(s):

Functional Groups ◽

Medicago Truncatula ◽

Root Nodules ◽

Bacterial Endophytes ◽

Host Genotype ◽

Model Legume ◽

Symbiotic Relationships ◽

Functional Assays ◽

Altered Gene ◽

Significant Direct Effect

Leguminous plants form symbiotic relationships with rhizobia. These nitrogen-fixing bacteria live in specialized root organs called nodules. While rhizobia form the most notable host relationship within root nodules, other bacterial endophytes also inhabit these root nodules and can influence host-rhizobia interactions as well as exert effects of their own, whether beneficial or detrimental. In this study, we investigate differences in nodule communities between genotypes (A17 and R108) of a single plant species, the model legume Medicago truncatula. While diversity of endophytes in nodules was similar across hosts, both nodule endophyte composition and gene functional groups differed. In contrast to the significant direct effect of host genotype, neither the presence nor identity of a host in the previous generation (either A17 or R108) had a significant effect on the nodule endophyte diversity or composition. However, whether or not a host was present altered gene functional groups. We conclude that genetic variation within a legume host species can play an important role in the establishment of nodule microbiomes. Further studies, including GWAS and functional assays, can open the door for engineering and optimizing nodule endophyte communities that promote growth or have other beneficial qualities.

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Diverse developmental mutants revealed in an activation-tagged population of poplarThis article is one of a selection of papers published on the Special Issue of Poplar Research in Canada.

Canadian Journal of Botany ◽

10.1139/b07-063 ◽

2007 ◽

Vol 85 (11) ◽

pp. 1071-1081 ◽

Cited By ~ 26

Author(s):

Edward J. Harrison ◽

Michael Bush ◽

Jonathan M. Plett ◽

Daniel P. McPhee ◽

Robin Vitez ◽

...

Keyword(s):

Large Scale ◽

Insertional Mutagenesis ◽

Hybrid Poplar ◽

Activation Tagging ◽

Developmental Abnormalities ◽

Endogenous Gene ◽

Developmental Mutants ◽

Poplar Trees ◽

Wide Range ◽

Mutant Lines

We have produced the largest population of activation-tagged poplar trees to date, approximately 1800 independent lines, and report on phenotypes of interest that have been identified in tissue culture and greenhouse conditions. Activation tagging is an insertional mutagenesis technique that results in the dominant upregulation of an endogenous gene. A large-scale Agrobacterium -mediated transformation protocol was used to transform the pSKI074 activation-tagging vector into Populus tremula × Populus alba hybrid poplar. We have screened the first 1000 lines for developmental abnormalities and have a visible mutant frequency of 2.4%, with alterations in leaf and stem structure as well as overall stature. Most of the phenotypes represent new phenotypes that have not previously been identified in poplar and, in some cases, not in any other plant either. Molecular analysis of the T-DNA inserts of a subpopulation of mutant lines reveal both single and double T-DNA inserts with double inserts more common in lines with visible phenotypes. The broad range of developmental mutants identified in this pilot screen of the population reveals that it will be a valuable resource for gene discovery in poplar. The full value of this population will only be realized as we screen these lines for a wide range of phenotypes.

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