scholarly journals 3D Domain Swapping Dimerization of the Receiver Domain of Cytokinin Receptor CRE1 From Arabidopsis thaliana and Medicago truncatula

2021 ◽  
Vol 12 ◽  
Author(s):  
Linh H. Tran ◽  
Anna Urbanowicz ◽  
Michał Jasiński ◽  
Mariusz Jaskolski ◽  
Milosz Ruszkowski
Keyword(s):  
Arabidopsis Thaliana ◽  
Medicago Truncatula ◽  
Response Regulator ◽  
Cytokinin Signaling ◽  
Modular Architecture ◽  
Model Legume ◽  
Cytokinin Receptor ◽  
Functional Studies ◽  
Receiver Domain ◽  
Transmembrane Fragment

Cytokinins are phytohormones regulating many biological processes that are vital to plants. CYTOKININ RESPONSE1 (CRE1), the main cytokinin receptor, has a modular architecture composed of a cytokinin-binding CHASE (Cyclases/Histidine kinases Associated Sensory Extracellular) domain, followed by a transmembrane fragment, an intracellular histidine kinase (HK) domain, and a receiver domain (REC). Perception of cytokinin signaling involves (i) a hormone molecule binding to the CHASE domain, (ii) CRE1 autophosphorylation at a conserved His residue in the HK domain, followed by a phosphorelay to (iii) a conserved Asp residue in the REC domain, (iv) a histidine-containing phosphotransfer protein (HPt), and (v) a response regulator (RR). This work focuses on the crystal structures of the REC domain of CRE1 from the model plant Arabidopsis thaliana and from the model legume Medicago truncatula. Both REC domains form tight 3D-domain-swapped dimers. Dimerization of the REC domain agrees with the quaternary assembly of the entire CRE1 but is incompatible with a model of its complex with HPt, suggesting that a considerable conformational change should occur to enable the signal transduction. Indeed, phosphorylation of the REC domain can change the HPt-binding properties of CRE1, as shown by functional studies.

scholarly journals Specific Host-Responsive Associations Between Medicago truncatula Accessions and Sinorhizobium Strains

2017 ◽  
Vol 30 (5) ◽  
pp. 399-409 ◽  
Author(s):  
Théophile Kazmierczak ◽  
Marianna Nagymihály ◽  
Florian Lamouche ◽  
Quentin Barrière ◽  
Ibtissem Guefrachi ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Sinorhizobium Meliloti ◽  
Root Nodules ◽  
Nodule Formation ◽  
Bacterial Strains ◽  
Symbiotic Efficiency ◽  
Model Legume ◽  
Functional Studies ◽  
Multiple Parameters ◽  
Nitrogen Fixation Activity

Legume plants interact with rhizobia to form nitrogen-fixing root nodules. Legume-rhizobium interactions are specific and only compatible rhizobia and plant species will lead to nodule formation. Even within compatible interactions, the genotype of both the plant and the bacterial symbiont will impact on the efficiency of nodule functioning and nitrogen-fixation activity. The model legume Medicago truncatula forms nodules with several species of the Sinorhizobium genus. However, the efficiency of these bacterial strains is highly variable. In this study, we compared the symbiotic efficiency of Sinorhizobium meliloti strains Sm1021, 102F34, and FSM-MA, and Sinorhizobium medicae strain WSM419 on the two widely used M. truncatula accessions A17 and R108. The efficiency of the interactions was determined by multiple parameters. We found a high effectiveness of the FSM-MA strain with both M. truncatula accessions. In contrast, specific highly efficient interactions were obtained for the A17-WSM419 and R108-102F34 combinations. Remarkably, the widely used Sm1021 strain performed weakly on both hosts. We showed that Sm1021 efficiently induced nodule organogenesis but cannot fully activate the differentiation of the symbiotic nodule cells, explaining its weaker performance. These results will be informative for the selection of appropriate rhizobium strains in functional studies on symbiosis using these M. truncatula accessions, particularly for research focusing on late stages of the nodulation process.

Comparative physical mapping reveals features of microsynteny between Glycine max, Medicago truncatula, and Arabidopsis thaliana

Genome ◽  
2004 ◽  
Vol 47 (1) ◽  
pp. 141-155 ◽  
Author(s):  
H H Yan ◽  
J Mudge ◽  
D-J Kim ◽  
R C Shoemaker ◽  
D R Cook ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Glycine Max ◽  
Medicago Truncatula ◽  
Physical Mapping ◽  
Large Scale ◽  
Sequence Similarity ◽  
Artificial Chromosome ◽  
Bac Contig ◽  
Cross Hybridization ◽  
Bac Contigs

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.

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

BMC Genomics ◽  
2014 ◽  
Vol 15 (1) ◽  
pp. 312 ◽  
Author(s):  
Haibao Tang ◽  
Vivek Krishnakumar ◽  
Shelby Bidwell ◽  
Benjamin Rosen ◽  
Agnes Chan ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Model Legume

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

2001 ◽  
Vol 14 (12) ◽  
pp. 1364-1367 ◽  
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.

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

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.

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

2016 ◽  
Vol 81 (3) ◽  
pp. 501-510 ◽  
Author(s):  
Elif Yüzbaşıoğlu ◽  
Eda Dalyan ◽  
Abdülrezzak Memon ◽  
Gül Öz ◽  
Bayram Yüksel
Keyword(s):  
Medicago Truncatula ◽  
Functional Specialization ◽  
Model Legume

scholarly journals Down-Regulation of Cytokinin Receptor Gene SlHK2 Improves Plant Tolerance to Drought, Heat, and Combined Stresses in Tomato

Plants ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 154
Author(s):  
Naveed Mushtaq ◽  
Yong Wang ◽  
Junmiao Fan ◽  
Yi Li ◽  
Jing Ding
Keyword(s):  
Abiotic Stress Tolerance ◽  
Receptor Gene ◽  
Antioxidant Enzyme Activities ◽  
Plant Responses ◽  
Plant Tolerance ◽  
Combined Stress ◽  
Cytokinin Signaling ◽  
Down Regulation ◽  
Cytokinin Receptor ◽  
Combined Stresses

Environmental stresses negatively affect the growth and development of plants. Several previous studies have elucidated the response mechanisms of plants to drought and heat applied separately; however, these two abiotic stresses often coincide in environmental conditions. The global climate change pattern has projected that combined drought and heat stresses will tend to increase in the near future. In this study, we down-regulated the expression of a cytokinin receptor gene SlHK2 using RNAi and investigated the role of this gene in regulating plant responses to individual drought, heat, and combined stresses (drought + heat) in tomato. Compared to the wild-type (WT), SlHK2 RNAi plants exhibited fewer stress symptoms in response to individual and combined stress treatments. The enhanced abiotic stress tolerance of SlHK2 RNAi plants can be associated with increased membrane stability, osmoprotectant accumulation, and antioxidant enzyme activities. Furthermore, photosynthesis machinery was also protected in SlHK2 RNAi plants. Collectively, our results show that down-regulation of the cytokinin receptor gene SlHK2, and consequently cytokinin signaling, can improve plant tolerance to drought, heat, and combined stress.

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

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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