Eva Kondorosi

Biological Research Centre, Hungarian Academy of Sciences | BRC · Institute of Biochemistry

Medicago truncatula in symbiosis with its rhizobial bacterium partner produces more than 700 nodule-specific cysteine-rich (NCR) peptides with diverse physicochemical properties. Most of the cationic NCR peptides have antimicrobial activity and the potential to tackle antimicrobial resistance with their novel modes of action. This work focuses on t...

Symbiotic nitrogen fixation by Rhizobium bacteria in the cells of legume root nodules alleviates the need for nitrogen fertilizers. Nitrogen fixation requires the endosymbionts to differentiate into bacteroids which can be reversible or terminal. The latter is controlled by the plant, it is more beneficial and has evolved in multiple clades of the...

Symbiotic nitrogen fixation by rhizobium bacteria within the cells of legume root nodules alleviates the need for nitrogen fertilizers. Nitrogen fixation requires the endosymbionts to differentiate into bacteroids and this can be reversible or terminal. The latter is controlled by the plant, is more beneficial and has evolved in a large clade of th...

Antimicrobial peptides are prominent components of the plant immune system acting against a wide variety of pathogens. Legume plants from the inverted repeat lacking clade (IRLC) have evolved a unique gene family encoding nodule-specific cysteine-rich NCR peptides acting in the symbiotic cells of root nodules, where they convert their bacterial end...

Legumes of the Medicago genus have a symbiotic relationship with the bacterium Sinorhizobium meliloti and develop root nodules housing large numbers of intracellular symbionts. Members of the nodule-specific cysteine-rich peptide (NCR) family induce the endosymbionts into a terminal differentiated state. Individual cationic NCRs are antimicrobial p...

In nitrogen-fixing nodules of legumes such as pea (Pisum) and Medicago spp. the plant induces terminal differentiation in the rhizobial endosymbionts by targeting nodule-specific cysteine-rich defensin-like peptides into the bacteria. However, in nodules of other legumes such as soybean and Lotus spp. terminal bacterial differentiation does not occ...

The increasing rate of fungal infections causes global problems not only in human healthcare but agriculture as well. To combat fungal pathogens limited numbers of antifungal agents are available therefore alternative drugs are needed. Antimicrobial peptides are potent candidates because of their broad activity spectrum and their diverse mode of ac...

Legumes of the Medicago genus form symbiosis with the bacterium Sinorhizobium meliloti and develop root nodules housing large numbers of the intracellular symbionts. Members of the Nodule-specific Cysteine Rich peptide (NCRs) family induce the endosymbionts into a terminal differentiated state. Individual cationic NCRs are antimicrobial peptides th...

During endosymbiosis, bacteria live intracellularly in the symbiotic organ of their host. The host controls the proliferation of endosymbionts and prevents their spread to other tissues and organs. In Rhizobium-legume symbiosis the major host effectors are secreted nodule-specific cysteine-rich (NCR) peptides, produced exclusively in the symbiotic...

In Rhizobium-legume symbiosis, the bacteria are converted into nitrogen-fixing bacteroids. In many legume species, differentiation of the endosymbiotic bacteria is irreversible, culminating in definitive loss of their cell division ability. This terminal differentiation is mediated by plant peptides produced in the symbiotic cells. In Medicago trun...

Root nodules formed by plants of the nitrogen-fixing clade (NFC) are symbiotic organs whose function is the maintenance and metabolic integration of large populations of nitrogen-fixing bacteria. These organs feature unique characteristics and processes, including their tissue organization, the presence of specific infection structures called infec...

The development and functioning of the nitrogen fixing symbiosis between legume plants and soil bacteria collectively called rhizobia requires continuous chemical dialogue between the partners using different molecules such as flavonoids, lipo-chitooligosaccharides, polysaccharides and peptides. Agrobacterium rhizogenes mediated hairy root transfor...

The symbiosis specific NCR247 and NCR335 cationic plant peptides of Medicago truncatula have been shown to exert antimicrobial activity against a wide range of microbes. However, their antimicrobial efficiency is clearly limited by divalent cations. Here, the antibacterial and antifungal activities of NCR247 and NCR335 peptides were compared to tho...

Ribosomally synthesized peptides have wide ranges of functions in plants being, for example, signal molecules, transporters, alkaloids, or antimicrobial agents. Legumes are an unprecedented rich source of peptides, which are used to control the symbiosis of these plants with the nitrogen-fixing Rhizobium bacteria. Here, we discuss the function and...

Significance Nitrogen is a limiting factor for plant growth. Most crops obtain their nitrogen through the use of nitrogen-based fertilizers, which is costly, and also causes environmental pollution. Legumes, however, have the unique ability to fix atmospheric nitrogen through symbioses with nitrogen-fixing bacteria. Although legumes can be nodulate...

Significance The mutualistic association between legumes and rhizobia has ecological and agronomical relevance because of its contribution to the global nitrogen cycle by biological nitrogen fixation. Legumes from the Inverted Repeat Lacking Clade (IRLC) impose irreversible differentiation to their endosymbionts through nodule-specific cysteine-ric...

Significance Polyploidization of somatic cells is common in angiosperms. The characteristic and inherited developmental pattern of polyploidy in various organs and cell types suggests a role for endoreduplication in differentiation and specialized cell functioning. Rhizobium -infected nodule cells provide a unique opportunity to study specific deve...

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 nit...

Background Certain legume plants produce a plethora of AMP-like peptides in their symbiotic cells. The cationic subgroup of the nodule-specific cysteine-rich (NCR) peptides has potent antimicrobial activity against gram-negative and gram-positive bacteria as well as unicellular and filamentous fungi. Findings It was shown by scanning and atomic fo...

Medicago and closely related legume species from the inverted repeat-lacking clade (IRLC) impose terminal differentiation onto their bacterial endosymbionts manifested in genome endoreduplication, cell enlargement and loss of cell division capacity. Nodule-specific cysteine-rich secreted host peptides (NCR) are plant effectors of this process. As b...

The importance and future potential of biological nitrogen-flxation is widely recognized. A further, yet unexplored and less known value of nitrogen-fixing root nodules is the presence of hundreds of plant peptides with antimicrobial activities and novel modes of action. These nodule-specific plant peptides are only produced in the Rhizobium-infect...

Significance In certain legume–rhizobia symbioses, the host plant is thought to control the terminal differentiation of its bacterial partner leading to nitrogen fixation. In Medicago truncatula , over 600 genes coding for nodule-specific cysteine-rich (NCR) peptides are expressed during nodule development and have been implicated in bacteroid diff...

To better understand the molecular events underlying vulvovaginal candidiasis, we established an in vitro system. Immortalized vaginal epithelial cells were infected with live, yeast form C. albicans and C. albicans cultured in the same medium without vaginal epithelial cells were used as control. In both cases a yeast to hyphae transition was robu...

RNA seq data was analyzed and differentially expressed genes between the C.a.3h vs. C.a.0h, PK+C.a.3h vs. C.a.0h and PK+C.a.3h vs. C.a.3h samples were listed. Since the hyphal form of C. albicans is pathogenic, genes with altered expression upon hyphal growth were collected. Our gene expression analysis revealed that the expression of genes involve...

The systemic host defence mechanisms, especially innate immunity, in venous leg ulcer patients are poorly investigated. The aim of the current study was to measure Candida albicans killing activity and gene expressions of pro- and anti-inflammatory cytokines and innate immune response regulators, TAM receptors and ligands of peripheral blood mononu...

The ability of legumes to acquire sufficient nitrogen from the symbiosis with Rhizobium relies on the intimate contact between the endosymbiotic, intracellular rhizobia, called bacteroids, and their host cells, the symbiotic nodule cells. Nodules contain several thousand symbiotic cells, each harboring thousands of bacteroids. Bacteroids are differ...

Leguminous plants live in symbiosis with nitrogen-fixing soil bacteria known as rhizobia. Symbiotic nitrogen fixation occurs in specialized root organs called nodules. Bacteria penetrate into the plant cells and are encapsulated by a plant-derived peribacteroid membrane forming an organelle-like structure, the symbiosome. Within the symbiosome, bac...

The ability of legumes to acquire sufficient nitrogen from the symbiosis with Rhizobium relies on the intimate contact between the endosymbiotic, intracellular rhizobia, called bacteroids, and their host cells, the symbiotic nodule cells. Nodules contain several thousand symbiotic cells, each harboring thousands of bacteroids. Bacteroids are differ...

Nodules of legume plants are highly integrated symbiotic systems shaped by millions of years of evolution. They harbor nitrogen-fixing rhizobium bacteria called bacteroids. Several legume species produce peptides called nodule-specific cysteine-rich (NCR) peptides in the symbiotic nodule cells which house the bacteroids. NCR peptides are related to...

The growing concern regarding the use of agricultural land for the production of biomass for food/feed or energy is dictating the search for alternative biomass sources. Photosynthetic microorganisms grown on marginal or deserted land present a promising alternative to the cultivation of energy plants and thereby may dampen the 'food or fuel' dispu...

Antimicrobial peptides are small proteins that exhibit a broad spectrum of antimicrobial activity. Their chemical structure allows them to interact (attach and insert) with membranes. The fine details about this interaction and their mode of action are not fully clarified yet. In order to better understand this mechanism, we have performed in situ...

The symbiosis of Medicago truncatula with Sinorhizobium meliloti or S. medicae soil bacteria results in the formation of root nodules where bacteria inside the plant cells are irreversibly converted to polyploid, non-dividing nitrogen-fixing bacteroids. Bacteroid differentiation is host-controlled and the plant effectors are symbiosis-specific secr...

Background: Biohydrogen production through dark fermentation using organic waste as a substrate has gained increasing attention in recent years, mostly because of the economic advantages of coupling renewable, clean energy production with biological waste treatment. An ideal approach is the use of selected microbial inocula that are able to degrad...

Legume root nodules are induced by N-fixing rhizobium bacteria that are hosted in an intracellular manner. These nodules are formed by reprogramming differentiated root cells. The model legume Medicago truncatula forms indeterminate nodules with a meristem at their apex. This organ grows by the activity of the meristem that adds cells to the differ...

The increasing number of multidrug-resistant microbes now emerging necessitates the identification of novel antimicrobial agents. Plants produce a great variety of antimicrobial peptides including hundreds of small, nodule-specific cysteine-rich NCR peptides that, in the legume Medicago truncatula, govern the differentiation of endosymbiotic nitrog...

Supplementary Figure 1: Representative output of an RTCA experiment.

Background Legumes form root nodules to house nitrogen fixing bacteria of the rhizobium family. The rhizobia are located intracellularly in the symbiotic nodule cells. In the legume Medicago truncatula these cells produce high amounts of Nodule-specific Cysteine-Rich (NCR) peptides which induce differentiation of the rhizobia into enlarged, polyplo...

The green algae Chlamydomonas sp. MACC-549 and Chlamydomonas reinhardtii cc124 were investigated for their hydrogen-evolution capability in mixed algal–bacterial cultures. Stable bacterial contaminations were identified during the cultivation of Chlamydomonas sp. 549. The bacterial symbionts belonged to various genera, mostly Brevundimonas, Rhodoco...

The green algae Chlamydomonas sp. MACC-549 and Chlamydomonas reinhardtii cc124 were investigated for their hydrogen-evolution capability in mixed algal-bacterial cultures. Stable bacterial contaminations were identified during the cultivation of Chlamydomonas sp. 549. The bacterial symbionts belonged to various genera, mostly Brevundimonas, Rhodoco...

The symbiosis between rhizobia soil bacteria and legumes is facultative and initiated by nitrogen starvation of the host plant. Exchange of signal molecules between the partners leads to the formation of root nodules where bacteria are converted to nitrogen-fixing bacteroids. In this mutualistic symbiosis, the bacteria provide nitrogen sources for...

Even in asymptomatic cases of Chlamydia trachomatis infection, the aim of the antibiotic strategy is eradication of the pathogen so as to avoid the severe late sequelae, such as pelvic inflammatory disease, ectopic pregnancy, and tubal infertility. Although first-line antimicrobial agents have been demonstrated to be predominantly successful in the...

The presence of specialized microbial associations between populations of chemoautotrophic bacteria and archaea with ascomycetous fungi was observed inside stalactite-shaped mineral formations in a highly acidic cave environment. Metagenomic, chemical and electron microscopy analyses were used to investigate the relevance of these microbial ecosyst...

Biohydrogen production through dark fermentation using different organic wastes as fermentation substrate gained increasing attention in the recent years, mostly because of the economic advantages of coupling renewable, clean energy production with biological waste treatment. An ideal approach is the use of selected microbial inocula able to degrad...

Significance Intracellular endosymbiotic bacteria in diverse symbiotic systems are under the control of host-derived symbiosis-specific peptides. These peptides have mostly unknown activities. In the facultative rhizobium-legume symbiosis, the bacteria differentiate in many legumes to large polyploid noncultivable bacteroids. This terminal differen...

Biohydrogen production from synthetic wastewater as substrate was studied in anaerobic small scale batch reactors. Enriched anaerobic mixed consortia sampled from various environments were used as parent inocula to start the bioreactors. Selective enrichments were achieved by various physical and chemical pretreatments and changes in the microbial...

Transcription factors (TFs) are thought to regulate many aspects of nodule and symbiosis development in legumes, although few TFs have been characterized functionally. Here, we describe REGULATOR OF SYMBIOSOME DIFFERENTIATION (RSD) of Medicago truncatula, a member of the Cysteine-2/Histidine-2 (C2H2) family of plant TFs that is required for normal...

Activation of dendritic cells by different pathogens induces the secretion of proinflammatory mediators resulting in local inflammation. Importantly, innate immunity must be properly controlled, as its continuous activation leads to the development of chronic inflammatory diseases such as psoriasis. Lipopolysaccharide (LPS) or peptidoglycan (PGN) i...

Symbiosis between Rhizobium bacteria and legumes leads to the formation of the root nodule. The endosymbiotic bacteria reside in polyploid host cells as membrane-surrounded vesicles where they reduce atmospheric nitrogen to support plant growth by supplying ammonia in exchange for carbon sources and energy. The morphology and physiology of endosymb...

Leguminous plants establish symbiosis with nitrogen-fixing α- and β-Proteobacteria, collectively called rhizobia, which provide combined nitrogen to support plant growth. Members of the Inverted Repeat-Lacking Clade of legumes impose terminal differentiation on their endosymbiotic bacterium partners with the help of the nodule-specific cysteine-ric...

Biohydrogen production through dark fermentation using organic wastes as a substrate has gained more and more attention in the last years, mostly because of the economic advantages of coupling renewable, clean energy production with biological waste treatments. Unfortunately there are still a series of improvements needed to be done in order to ach...

Biohydrogen production from synthetic wastewater as substrate was studied in anaerobic small scale batch reactors. Enriched anaerobic mixed consortia sampled from various environments were used as parent inoculums to start the bioreactors. Selective enrichments were achieved by various physical and chemical pretreatments. Process evolution was stud...

Propionibacterium avidum is an anaerobic Gram-positive bacterium that forms part of the normal human cutaneous microbiota, colonizing moist areas such as the vestibule of the nose, axilla, and perineum. Here we present the complete genome sequence of P. avidum strain 44067, which was isolated from a carbuncle of the trunk.

The dimension of organs depends on the number and the size of their component cells. Formation of polyploid cells by endoreduplication cycles is predominantly associated with increases in the cell size and implicated in organ growth. In plants, the CCS 52 A proteins play a major role in the switch from mitotic to endoreduplication cycles controllin...

Nonsense-mediated mRNA decay (NMD) is a eukaryotic quality control system that identifies and degrades mRNAs containing premature termination codons (PTCs). If translation terminates at a PTC, the UPF1 NMD factor binds the terminating ribosome and recruits UPF2 and UPF3 to form a functional NMD complex, which triggers the rapid decay of the PTC-con...

The production of antimicrobial peptides (AMPs) in response to invading pathogenic microbes is an effective and ancient innate immune strategy which is conserved in all analyzed present-day eukaryotes. However, organisms are not only threatened by microbes but on the contrary, they often form beneficial symbiotic associations with them. There is a...

Symbiosomes are organelle-like structures in the cytoplasm of legume nodule cells which are composed of the special, nitrogen-fixing forms of rhizobia called bacteroids, the peribacteroid space and the enveloping peribacteroid membrane of plant origin. The formation of these symbiosomes requires a complex and coordinated interaction between the two...

Mass spectrometry and HPLC analysis of NCR247 peptide. (A) ESI-MS of the NCR247 peptide. This analysis is in agreement with a peptide of 3004.5 Da and demonstrates the correct localization of the S-S bridges. (B) RP-HPLC analysis of the NCR247 peptide. The arrow indicates the single peptide peak with greater than 95% purity. (TIF)

BacA proteins protect S. meliloti in vitro against the antimicrobial activity of NCR035. (A) NCR035 peptide sequence with the conserved cysteine residues in bold and underlined. (B) Colony forming ability of the indicated strains was assessed after exposure towards 30 µM NCR035 peptide for 3 h. Bars represent mean ± SD. The significance value **p≤0...

The hypersensitivity of the BacA-deficient S. meliloti mutant towards NCR247 is complemented by reintroduction of the S. meliloti bacA gene or the B. abortus bacA gene. Colony forming ability in the indicated strains was assessed after exposure towards 20 µM of the NCR247 peptide for 3 h. Control vector (pRF771), wild-type S. meliloti bacA gene clo...

NCR035 and NCR084 are transported to symbiosomes, even in the absence of bacterial BacA. Confocal microscopy of the S. meliloti wild-type (A,C,E) and BacA-deficient mutant (B,D,F) strains infected transgenic nodules expressing NCR035-mCHERRY under the control of the NCR035 promoter (A–D) or NCR084-mCHERRY under the control of the NCR084 promoter (E...

The S. meliloti BacA-deficient mutant undergoes rapid death in symbiosomes. Confocal microscopy of either the S. meliloti wild-type strain-infected nodules (A,C) or the BacA-deficient mutant-infected nodules (B,D) from wild-type M. truncatula (A,B) and from an M. truncatula dnf1 mutant (C,D) stained with a mixture of SYTO9 (green signal) and PI (re...

Viability of symbiosome bacteria in the M. truncatula dnf-1 mutant nodules. (A–C) Confocal microscopy of S. meliloti wild-type-infected dnf1 nodules stained with a mixture of SYTO9 (green signal) and PI (red signal). (C) Enlargement of the image in (B). These nodules have an extended zone with symbiotic cells containing live bacteria stained with S...

NCR247 peptide induces bacteroid-like features in cultured S. meliloti. Flow cytometry analysis of the in vitro S. meliloti wild-type strain (A–D) or the BacA-deficient mutant (E–H) with (shaded peaks, solid lines) and without (white peaks, dashed lines) 2 µM (A,B,E,F) or 4 µM NCR247 (C,D,G,H) exposure for 3 h. The forward scatter (FSC) was measure...

RT-PCR analysis of NCR gene expression. Expression analysis of the indicated NCR genes in M. truncatula wild-type roots and nodules induced by either the S. meliloti wild-type strain or the BacA-deficient mutant. Histone 3-like (H3 like) is used as a constitutive control. (TIF)

Correlation between NCR gene expression in nodules, requirement of BacA, and bacteroid type. 1 Reported presence (yes) or absence (no) of NCR gene expression in nodules. 2 Requirement of BacA protein for efficient, nitrogen-fixing symbiosis; nd, no data available. 3 Mergaert et al., 2006 [3] and unpublished data. (DOC)

Sinorhizobium meliloti differentiates into persisting, nitrogen-fixing bacteroids within root nodules of the legume Medicago truncatula. Nodule-specific cysteine-rich antimicrobial peptides (NCR AMPs) and the bacterial BacA protein are essential for bacteroid development. However, the bacterial factors central to the NCR AMP response and the in pla...

Production of the Arabidopsis CDC20 isoforms and mitotic cyclins in yeast cells. The presence of CDC20 and cyclin proteins expressed from the Y2H pGADT7 vector was detected in yeast total protein extracts by Western Blot analysis with the anti-HA antibody. Upper panel, production of the five AtCDC20 proteins as indicated. Lower panel, production of...

Phylogenetic analysis of plant CDC20 proteins. The tree was generated using the alignment of Figure S1. Numbers next to the branches indicate the bootstrap values in %. The accession numbers of the proteins are as in Figure S1. The intron-exon organization of each gene is indicated, the conserved exons are in orange and fused exons are in blue, int...

Conservation of exon-intron boundaries in plant CDC20 genes. The alignment in Figure S1 was used to indicate with colored highlights the exons in the plant CDC20 genes. Yellow and green exons are conserved with respect to the AtCDC20.1 and AtCDC20.2 genes while exons in blue correspond to fused exons resulting from the loss of one or more introns....

Alignment of plant CDC20 proteins. The sequences are annotated by their accession numbers in the PLAZA database. The first two letters indicate the plant species: AL, Arabidopsis lyrata; AT, Arabidopsis thaliana; PT, Populus trichocarpa; CP, Carica papaya; GM, Glycine max; VV, Vitis vinifera; SB, Sorghum bicolor; ZM, Zea mays and OS, Oryza sativa....

The CDC20 and Cdh1/CCS52 proteins are substrate determinants and activators of the Anaphase Promoting Complex/Cyclosome (APC/C) E3 ubiquitin ligase and as such they control the mitotic cell cycle by targeting the degradation of various cell cycle regulators. In yeasts and animals the main CDC20 function is the destruction of securin and mitotic cyc...