Infection Reinforces the Defense Reactions in - Roots to the Detriment of Nodules.

, able to establish symbiosis with mutualistic bacteria of the genus , is one of the main species in European riparian environments, where it performs numerous biological and socioeconomic functions. However, riparian ecosystems face a growing threat from , a highly aggressive waterborne pathogen causing severe dieback in . To date, the tripartite interaction between the host plant, the symbiont , and the pathogen remains unexplored but is critical for understanding how pathogen-induced stress influences the nodule molecular machinery and thus the host-symbiont metabolism.

sp. nov., a non-infective non-nitrogen-fixing isolate from root nodules of Wall.

Strains CN4, CN6, CN7 and CNm7 were isolated from root nodules of from Murree in Pakistan. They do not form root nodules on nor on although they deformed root hairs of . The colonies are bright red-pigmented, the strains form hyphae and sporangia but no N-fixing vesicles and do not fix nitrogen .

Identification and evolution of nsLTPs in the root nodule nitrogen fixation clade and molecular response of Frankia to AgLTP24.

Non-specific lipid transfer proteins (nsLTPs) are antimicrobial peptides, involved in several plant biological processes including root nodule nitrogen fixation (RNF). Nodulating plants belonging to the RNF clade establish symbiosis with the nitrogen-fixing bacteria rhizobia (legumes symbiosis model) and Frankia (actinorhizal symbiosis model) leading to root nodule formation. nsLTPs are involved in processes active in early step of symbiosis and functional nodule in both models.

Comparative phylogenomics and phylotranscriptomics provide insights into the genetic complexity of nitrogen-fixing root-nodule symbiosis.

Plant root-nodule symbiosis (RNS) with mutualistic nitrogen-fixing bacteria is restricted to a single clade of angiosperms, the Nitrogen-Fixing Nodulation Clade (NFNC), and is best understood in the legume family. Nodulating species share many commonalities, explained either by divergence from a common ancestor over 100 million years ago or by convergence following independent origins over that same time period. Regardless, comparative analyses of diverse nodulation syndromes can provide insights into constraints on nodulation-what must be acquired or cannot be lost for a functional symbiosis-and the latitude for variation in the symbiosis.

Carbonic Anhydrase Regulates Cytoplasmic pH of Nitrogen-Fixing Vesicles.

A phyloprofile of genomes was carried out to identify those genes present in symbiotic strains of clusters 1, 1c, 2 and 3 and absent in non-infective strains of cluster 4. At a threshold of 50% AA identity, 108 genes were retrieved. Among these were known symbiosis-associated genes such as (nitrogenase), and genes which are not know as symbiosis-associated genes such as (carbonic anhydrase, CAN).

Genomic Insights of -Infective Strains Reveal Unique Genetic Features and New Evidence on Their Host-Restricted Lifestyle.

The present study aimed to use comparative genomics to explore the relationships between and actinorhizal plants using a data set made of 33 genomes. The determinants of host specificity were first explored for "-infective strains" (i.e.

Correction: Pujic et al. The Proteogenome of Symbiotic in Nodules. 2022, , 651.

The authors wish to make the following corrections to this paper [...

A Nonspecific Lipid Transfer Protein with Potential Functions in Infection and Nodulation.

The response of to ACN14a is driven by several sequential physiological events from calcium spiking and root-hair deformation to the development of the nodule. Early stages of actinorhizal symbiosis were monitored at the transcriptional level to observe plant host responses to . Forty-two genes were significantly upregulated in inoculated compared with noninoculated roots.

The Proteogenome of Symbiotic in Nodules.

Omics are the most promising approaches to investigate microbes for which no genetic tools exist such as the nitrogen-fixing symbiotic A proteogenomic analysis of symbiotic was done by comparing those proteins more and less abundant in nodules relative to N-fixing pure cultures with propionate as the carbon source. There were 250 proteins that were significantly overabundant in nodules at a fold change (FC) ≥ 2 threshold, and 1429 with the same characteristics in in vitro nitrogen-fixing pure culture. Nitrogenase, SuF (Fe-Su biogenesis) and hopanoid lipids synthesis determinants were the most overabundant proteins in symbiosis.

Candidatus Frankia nodulisporulans sp. nov., an Alnus glutinosa-infective Frankia species unable to grow in pure culture and able to sporulate in-planta.

We describe a new Frankia species, for three non-isolated strains obtained from Alnus glutinosa in France and Sweden, respectively. These strains can nodulate several Alnus species (A. glutinosa, A.

Proposal of ' Frankia alpina', the uncultured symbiont of and that forms spore-containing nitrogen-fixing root nodules.

The members of the genus are, with a few exceptions, a group of nitrogen-fixing symbiotic actinobacteria that nodulate mostly woody dicotyledonous plants belonging to three orders, eight families and 23 genera of pioneer dicots. These bacteria have been characterized phylogenetically and grouped into four molecular clusters. One of the clusters, cluster 1 contains strains that induce nodules on spp.

Feedback Regulation of N Fixation in Symbiosis Through Amino Acids Profiling in Field and Greenhouse Nodules.

Symbiosis established between actinorhizal plants and spp., which are nitrogen-fixing actinobacteria, promotes nodule organogenesis, the site of metabolic exchange. The present study aimed to identify amino acid markers involved in - interactions by comparing nodules and associated roots from field and greenhouse samples.

Genome Sequence of sp. Strain ST1, Isolated from Olive (Olea europaea L.) Knot Galls in Croatia.

We report the genome sequence of a sp. strain isolated from olive knot galls. The genome size is 6.

Draft genome sequences for three unisolated -infective Sp+ strains, AgTrS, AiOr and AvVan, the first sequenced strains able to sporulate .

Actinobacteria from genus are able to form symbiotic associations with actinorhizal plants including alders. Among them, Sp+ strains are characterized by their ability to differentiate numerous sporangia inside host plant cells (unlike "Sp-" strains unable of sporulation). Here, we report the first genome sequences of three unisolated Sp+ strains: AgTrS, AiOr and AvVan obtained from , and (previously known as ), respectively (with genome completeness estimated at more than 98%).

Comparative genomics and proteogenomics highlight key molecular players involved in Frankia sporulation.

Sporulation is a microbial adaptive strategy to resist inhospitable conditions for vegetative growth and to disperse to colonise more favourable environments. This microbial trait is widespread in Actinobacteria. Among them, Frankia strains are able to differentiate sporangia in pure culture, while others can sporulate even when in symbiosis with sporulation occurring within host cells.

Omics of the early molecular dialogue between Frankia alni and Alnus glutinosa and the cellulase synton.

The early Frankia-Alnus symbiotic molecular exchanges were analyzed in detail by protein and RNA omics. For this, Frankia cells were placed in the presence of Alnus roots but separated by a dialysis membrane for 64 h. The bacterial cells were then harvested and analyzed by high-throughput proteomics and transcriptomics (RNA-seq).

Actinorhizal Signaling Molecules: Root Hair Deforming Factor Shares Properties With NIN Inducing Factor.

Actinorhizal plants are able to establish a symbiotic relationship with bacteria leading to the formation of root nodules. The symbiotic interaction starts with the exchange of symbiotic signals in the soil between the plant and the bacteria. This molecular dialog involves signaling molecules that are responsible for the specific recognition of the plant host and its endosymbiont.

Frankia canadensis sp. nov., isolated from root nodules of Alnus incana subspecies rugosa.

Strain ARgP5, an actinobacterium isolated from a root nodule present on an Alnus incana subspecies rugosa shrub growing in Quebec City, Canada, was the subject of polyphasic taxonomic studies to clarify its status within the genus Frankia. 16S rRNA gene sequence similarities and ANI values between ARgP5 and type strains of species of the genus Frankiawith validly published names were 98.8 and 82 % or less, respectively.

Molecular response to nitrogen starvation by Frankia alni ACN14a revealed by transcriptomics and functional analysis with a fosmid library in Escherichia coli.

The transcriptome of Frankia alni strain ACN14a was compared between in vitro ammonium-replete (N-replete) and ammonium-free dinitrogen-fixing (N-fixing) conditions using DNA arrays. A Welch-test (p < 0.05) revealed significant upregulation of 252 genes under N-fixing vs.

The PEG-responding desiccome of the alder microsymbiont Frankia alni.

Actinorhizal plants are ecologically and economically important. Symbiosis with nitrogen-fixing bacteria allows these woody dicotyledonous plants to colonise soils under nitrogen deficiency, water-stress or other extreme conditions. However, proteins involved in xerotolerance of symbiotic microorganisms have yet to be identified.

Physiological effects of major up-regulated Alnus glutinosa peptides on Frankia sp. ACN14a.

Alnus glutinosa has been shown previously to synthesize, in response to nodulation by Frankia sp. ACN14a, an array of peptides called Alnus symbiotic up-regulated peptides (ASUPs). In a previous study one peptide (Ag5) was shown to bind to Frankia nitrogen-fixing vesicles and to modify their porosity.

In-planta Sporulation Capacity Enhances Infectivity and Rhizospheric Competitiveness of Frankia Strains.

Frankia Sp+ strains maintain their ability to sporulate in symbiosis with actinorhizal plants, producing abundant sporangia inside host plant cells, in contrast to Sp- strains, which are unable to perform in-planta sporulation. We herein examined the role of in-planta sporulation in Frankia infectivity and competitiveness for root infection. Fifteen strains belonging to different Sp+ and Sp- phylogenetic lineages were inoculated on seedlings of Alnus glutinosa (Ag) and A.

Genome Sequence of the Atypical Symbiotic Frankia R43 Strain, a Nitrogen-Fixing and Hydrogen-Producing Actinobacterium.

Frankia strain R43 is a nitrogen-fixing and hydrogen-producing symbiotic actinobacterium that was isolated from nodules of Casuarina cunninghamiana but infects only Elaeagnaceae. This communication reports the genome of the strain R43 and provides insights into the microbe genomics and physiological potentials.

Candidatus Frankia Datiscae Dg1, the Actinobacterial Microsymbiont of Datisca glomerata, Expresses the Canonical nod Genes nodABC in Symbiosis with Its Host Plant.

Frankia strains are nitrogen-fixing soil actinobacteria that can form root symbioses with actinorhizal plants. Phylogenetically, symbiotic frankiae can be divided into three clusters, and this division also corresponds to host specificity groups. The strains of cluster II which form symbioses with actinorhizal Rosales and Cucurbitales, thus displaying a broad host range, show suprisingly low genetic diversity and to date can not be cultured.

Alnus peptides modify membrane porosity and induce the release of nitrogen-rich metabolites from nitrogen-fixing Frankia.

Actinorhizal plant growth in pioneer ecosystems depends on the symbiosis with the nitrogen-fixing actinobacterium Frankia cells that are housed in special root organs called nodules. Nitrogen fixation occurs in differentiated Frankia cells known as vesicles. Vesicles lack a pathway for assimilating ammonia beyond the glutamine stage and are supposed to transfer reduced nitrogen to the plant host cells.