scholarly journals Hopanoids confer robustness to physicochemical variability in the niche of the plant symbiont Bradyrhizobium diazoefficiens

2021 ◽  
Author(s):  
Elise M Tookmanian ◽  
Lisa Junghans ◽  
Gargi Kulkarni ◽  
Raphael Ledermann ◽  
James Peter Saenz ◽  
...  
Keyword(s):  
Climate Change ◽  
Environmental Variability ◽  
Root Nodules ◽  
Soil Health ◽  
In Planta ◽  
Growth Defects ◽  
Plant Symbiont ◽  
Fitness Advantage ◽  
And Function

Climate change poses a threat to soil health and agriculture, but the potential effects of climate change on soil bacteria that can help maintain soil health are understudied. Rhizobia are a group of bacteria that increase soil nitrogen content through a symbiosis with legume plants. The soil and symbiosis are potentially stressful environments, and the soil will likely become even more stressful as the climate changes. Many rhizobia within the bradyrhizobia clade, like Bradyrhizobium diazoefficiens, possess the genetic capacity to synthesize hopanoids, steroid-like lipids similar in structure and function to cholesterol. Hopanoids are known to protect against stresses relevant to the niche of B. diazoefficiens. Paradoxically, mutants unable to synthesize the extended class of hopanoids participate in similarly successful symbioses compared to the wild type, despite being delayed in root nodule initiation. Here, we show that in B. diazoefficiens, the in vitro growth defects of extended hopanoid deficient mutants can be at least partially compensated for by the physicochemical environment, specifically by optimal osmotic and divalent cation concentrations. Through biophysical measurements, we show that extended hopanoids confer robustness to environmental variability. These results help explain the discrepancy between previous in vitro and in planta results and indicate that hopanoids may provide a greater fitness advantage to rhizobia in the variable soil environment than the more controlled environment within root nodules. To improve the legume-rhizobia symbiosis through either bioengineering or strain selection, it will be important to consider the full lifecycle of rhizobia, from the soil to the symbiosis.

Strain distribution and in planta production of an extracellular polysaccharide depolymerase from Bradyrhizobium japonicum

1992 ◽  
Vol 38 (8) ◽  
pp. 857-861 ◽  
Author(s):  
Michael F. Dunn ◽  
Arthur L. Karr
Keyword(s):  
Bradyrhizobium Japonicum ◽  
Root Nodules ◽  
Extracellular Polysaccharide ◽  
Extracellular Polysaccharides ◽  
Neutral Sugar ◽  
In Planta ◽  
In Vitro Production ◽  
Polysaccharide Composition ◽  
Vitro Production

Thirty-four strains of Bradyrhizobium japonicum were screened for the in vitro production of an extracellular polysaccharide depolymerase active against the B. japonicum acidic extracellular polysaccharide that contains mannose, glucose, galactose, and 4-O-methylgalactose as neutral sugar components. Over 90% of tested strains producing this type of extracellular polysaccharide also produced the extracellular polysaccharide depolymerase, whereas strains producing a compositionally different extracellular polysaccharide did not. In addition, representatives of species related to B. japonicum by extracellular polysaccharide composition or host range were also phenotypically depolymerase negative. Depolymerase was also present in soybean root nodules formed by B. japonicum strain 2143. In contrast to the cell-associated depolymerase activity found in free-living cells of this strain, most of the depolymerase activity present in nodules is free of the bacteroids. The widespread occurrence of the depolymerase among B. japonicum strains and the spatiotemporal distribution of its activity in planta are consistent with the enzyme playing a role in the removal of surface extracellular polysaccharide from the microorganism during the infection of nodulation process. Key words: Bradyrhizobium japonicum, soybean, extracellular polysaccharides, extracellular polysaccharide depolymerase, bacteroids.

scholarly journals HC-Pro protein of sugar cane mosaic virus interacts specifically with maize ferredoxin-5 in vitro and in planta

2008 ◽  
Vol 89 (8) ◽  
pp. 2046-2054 ◽  
Author(s):  
Yu-Qin Cheng ◽  
Zhong-Mei Liu ◽  
Jian Xu ◽  
Tao Zhou ◽  
Meng Wang ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Sugar Cane ◽  
Transit Peptide ◽  
Viral Disease ◽  
Middle Part ◽  
Symptom Development ◽  
In Planta ◽  
Maize Plants ◽  
And Function

Symptom development of a plant viral disease is a result of molecular interactions between the virus and its host plant; thus, the elucidation of specific interactions is a prerequisite to reveal the mechanism of viral pathogenesis. Here, we show that the chloroplast precursor of ferredoxin-5 (Fd V) from maize (Zea mays) interacts with the multifunctional HC-Pro protein of sugar cane mosaic virus (SCMV) in yeast, Nicotiana benthamiana cells and maize protoplasts. Our results demonstrate that the transit peptide rather than the mature protein of Fd V precursor could interact with both N-terminal (residues 1–100) and C-terminal (residues 301–460) fragments, but not the middle part (residues 101–300), of HC-Pro. In addition, SCMV HC-Pro interacted only with Fd V, and not with the other two photosynthetic ferredoxin isoproteins (Fd I and Fd II) from maize plants. SCMV infection significantly downregulated the level of Fd V mRNA in maize plants; however, no obvious changes were observed in levels of Fd I and Fd II mRNA. These results suggest that SCMV HC-Pro interacts specifically with maize Fd V and that this interaction may disturb the post-translational import of Fd V into maize bundle-sheath cell chloroplasts, which could lead to the perturbation of chloroplast structure and function.

Multimerization and tubulin binding are required for the SPIRAL2 protein to localize to and stabilize microtubule minus ends

2021 ◽  
Author(s):  
YUANWEI FAN ◽  
Natasha Bilkey ◽  
Ram Dixit
Keyword(s):  
Coiled Coil ◽  
Spatial Arrangement ◽  
In Planta ◽  
Structural Determinants ◽  
Coiled Coil Domain ◽  
Tubulin Binding ◽  
And Function ◽  
Necessary And Sufficient ◽  
Basic Region

Accruing evidence points to the control of microtubule minus-end dynamics as being crucial for the spatial arrangement and function of the microtubule cytoskeleton. In plants, the SPIRAL2 (SPR2) protein has emerged as a microtubule minus-end regulator that is structurally distinct from the animal minus-end regulators. Previously, SPR2 was shown to autonomously localize to microtubule minus ends and decrease their depolymerization rate. Here, we used in vitro and in planta experiments to identify the structural determinants required for SPR2 to recognize and stabilize microtubule minus ends. We show that SPR2 contains a single N-terminal TOG domain that binds to soluble tubulin. The TOG domain, a basic region, and coiled-coil domain are necessary and sufficient to target and stabilize microtubule minus ends. We demonstrate that the coiled-coil domain mediates multimerization of SPR2 that provides avidity for microtubule binding and is essential for binding to soluble tubulin. While TOG domain-containing proteins are traditionally thought to function as microtubule plus-end regulators, our results reveal that nature has repurposed the TOG domain of SPR2 to regulate microtubule minus ends.

scholarly journals Scenarios of Genes-to-Terpenoids Network Led to the Identification of a Novel α/β-Farnesene/β-Ocimene Synthase in Camellia sinensis

2020 ◽  
Vol 21 (2) ◽  
pp. 655
Author(s):  
Jieyang Jin ◽  
Shangrui Zhang ◽  
Mingyue Zhao ◽  
Tingting Jing ◽  
Na Zhang ◽  
...  
Keyword(s):  
Function Analysis ◽  
Pearson Correlation ◽  
Integrated Approach ◽  
In Planta ◽  
Terpene Synthases ◽  
Gene Transcripts ◽  
Pearson Correlation Analysis ◽  
Tea Plants ◽  
And Function

Terpenoids play vital roles in tea aroma quality and plants defense performance determination, whereas the scenarios of genes to metabolites of terpenes pathway remain uninvestigated in tea plants. Here, we report the use of an integrated approach combining metabolites, target gene transcripts and function analyses to reveal a gene-to-terpene network in tea plants. Forty-one terpenes including 26 monoterpenes, 14 sesquiterpenes and one triterpene were detected and 82 terpenes related genes were identified from five tissues of tea plants. Pearson correlation analysis resulted in genes to metabolites network. One terpene synthases whose expression positively correlated with farnesene were selected and its function was confirmed involved in the biosynthesis of α-farnesene, β-ocimene and β-farnesene, a very important and conserved alarm pheromone in response to aphids by both in vitro enzymatic assay in planta function analysis. In summary, we provided the first reliable gene-to-terpene network for novel genes discovery.

scholarly journals Mutational Analysis of Residues in PriA and PriC Affecting Their Ability To Interact with SSB in Escherichia coli K-12

2020 ◽  
Vol 202 (23) ◽  
Author(s):  
Anastasiia N. Klimova ◽  
Steven J. Sandler
Keyword(s):  
Escherichia Coli ◽  
Mutational Analysis ◽  
Wild Type ◽  
Content Type ◽  
Growth Defects ◽  
C Terminus ◽  
K 12 ◽  
And Function

ABSTRACT Escherichia coli PriA and PriC recognize abandoned replication forks and direct reloading of the DnaB replicative helicase onto the lagging-strand template coated with single-stranded DNA-binding protein (SSB). Both PriA and PriC have been shown by biochemical and structural studies to physically interact with the C terminus of SSB. In vitro, these interactions trigger remodeling of the SSB on ssDNA. priA341(R697A) and priC351(R155A) negated the SSB remodeling reaction in vitro. Plasmid-carried priC351(R155A) did not complement priC303::kan, and priA341(R697A) has not yet been tested for complementation. Here, we further studied the SSB-binding pockets of PriA and PriC by placing priA341(R697A), priA344(R697E), priA345(Q701E), and priC351(R155A) on the chromosome and characterizing the mutant strains. All three priA mutants behaved like the wild type. In a ΔpriB strain, the mutations caused modest increases in SOS expression, cell size, and defects in nucleoid partitioning (Par−). Overproduction of SSB partially suppressed these phenotypes for priA341(R697A) and priA344(R697E). The priC351(R155A) mutant behaved as expected: there was no phenotype in a single mutant, and there were severe growth defects when this mutation was combined with ΔpriB. Analysis of the priBC mutant revealed two populations of cells: those with wild-type phenotypes and those that were extremely filamentous and Par− and had high SOS expression. We conclude that in vivo, priC351(R155A) identified an essential residue and function for PriC, that PriA R697 and Q701 are important only in the absence of PriB, and that this region of the protein may have a complicated relationship with SSB. IMPORTANCE Escherichia coli PriA and PriC recruit the replication machinery to a collapsed replication fork after it is repaired and needs to be restarted. In vitro studies suggest that the C terminus of SSB interacts with certain residues in PriA and PriC to recruit those proteins to the repaired fork, where they help remodel it for restart. Here, we placed those mutations on the chromosome and tested the effect of mutating these residues in vivo. The priC mutation completely abolished function. The priA mutations had no effect by themselves. They did, however, display modest phenotypes in a priB-null strain. These phenotypes were partially suppressed by SSB overproduction. These studies give us further insight into the reactions needed for replication restart.

scholarly journals Loss of the nodule-specific cysteine rich peptide, NCR169, abolishes symbiotic nitrogen fixation in the Medicago truncatula dnf7 mutant

2015 ◽  
Vol 112 (49) ◽  
pp. 15232-15237 ◽  
Author(s):  
Beatrix Horváth ◽  
Ágota Domonkos ◽  
Attila Kereszt ◽  
Attila Szűcs ◽  
Edit Ábrahám ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Medicago Truncatula ◽  
Symbiotic Nitrogen Fixation ◽  
Root Nodules ◽  
Nitrogen Fixing ◽  
In Planta ◽  
Functional Roles ◽  
Absolute Requirement ◽  
Cell Layers

Host compatible rhizobia induce the formation of legume root nodules, symbiotic organs within which intracellular bacteria are present in plant-derived membrane compartments termed symbiosomes. In Medicago truncatula nodules, the Sinorhizobium microsymbionts undergo an irreversible differentiation process leading to the development of elongated polyploid noncultivable nitrogen fixing bacteroids that convert atmospheric dinitrogen into ammonia. This terminal differentiation is directed by the host plant and involves hundreds of nodule specific cysteine-rich peptides (NCRs). Except for certain in vitro activities of cationic peptides, the functional roles of individual NCR peptides in planta are not known. In this study, we demonstrate that the inability of M. truncatula dnf7 mutants to fix nitrogen is due to inactivation of a single NCR peptide, NCR169. In the absence of NCR169, bacterial differentiation was impaired and was associated with early senescence of the symbiotic cells. Introduction of the NCR169 gene into the dnf7-2/NCR169 deletion mutant restored symbiotic nitrogen fixation. Replacement of any of the cysteine residues in the NCR169 peptide with serine rendered it incapable of complementation, demonstrating an absolute requirement for all cysteines in planta. NCR169 was induced in the cell layers in which bacteroid elongation was most pronounced, and high expression persisted throughout the nitrogen-fixing nodule zone. Our results provide evidence for an essential role of NCR169 in the differentiation and persistence of nitrogen fixing bacteroids in M. truncatula.

scholarly journals Function of the HYDROXYCINNAMOYL-CoA:SHIKIMATE HYDROXYCINNAMOYL TRANSFERASE is evolutionarily conserved in embryophytes

2020 ◽  
Author(s):  
Lucie Kriegshauser ◽  
Samuel Knosp ◽  
Etienne Grienenberger ◽  
Kanade Tatsumi ◽  
Desirée D. Gütle ◽  
...  
Keyword(s):  
Phenylpropanoid Pathway ◽  
Evolutionary Significance ◽  
Marchantia Polymorpha ◽  
Loss Of Function ◽  
In Planta ◽  
Critical Function ◽  
Acyl Acceptor ◽  
Bona Fide ◽  
And Function

ABSTRACTThe plant phenylpropanoid pathway generates a major class of specialized metabolites and precursors of essential extracellular polymers that initially appeared upon plant terrestrialization. Despite its evolutionary significance, little is known about the complexity and function of this major metabolic pathway in extant bryophytes, the ancestors of which were the first land plants. Here, we report that the HYDROXYCINNAMOYL-CoA:SHIKIMATE HYDROXYCINNAMOYL TRANSFERASE (HCT) gene, which plays a critical function in the phenylpropanoid pathway during seed plant development, is functionally conserved in Physcomitrium patens (Physcomitrella), in the moss lineage of bryophytes. Phylogenetic analysis indicates that bona fide HCT function emerged in the progenitor of embryophytes. In vitro enzyme assays, moss phenolic pathway reconstitution in yeast and in planta gene inactivation coupled to targeted metabolic profiling, collectively indicate that P. patens HCT (PpHCT), similar to tracheophyte HCT orthologs, uses shikimate as a native acyl acceptor to produce a p-coumaroyl-5-O-shikimate intermediate. Phenotypic and metabolic analyses of loss-of-function mutants show that PpHCT is necessary for the production of caffeate derivatives, including previously reported caffeoyl-threonate esters, and for the formation of an intact cuticle. Deep conservation of HCT function in embryophytes is further suggested by the ability of HCT genes from P. patens and the liverwort Marchantia polymorpha to complement an Arabidopsis thaliana CRISPR/Cas9 hct mutant, and by the presence of phenolic esters of shikimate in representative species of the three bryophyte lineages.

scholarly journals Cooperation, Competition, and Specialized Metabolism in a Simplified Root Nodule Microbiome

mBio ◽  
2020 ◽  
Vol 11 (4) ◽  
Author(s):  
Bridget L. Hansen ◽  
Rita de Cassia Pessotti ◽  
Monika S. Fischer ◽  
Alyssa Collins ◽  
Laila El-Hifnawi ◽  
...  
Keyword(s):  
Potential Role ◽  
Root Nodule ◽  
Root Nodules ◽  
Imaging Mass Spectrometry ◽  
In Planta ◽  
Content Type ◽  
Specialized Metabolites ◽  
Brevibacillus Brevis

ABSTRACT Microbiomes associated with various plant structures often contain members with the potential to make specialized metabolites, e.g., molecules with antibacterial, antifungal, or siderophore activities. However, when and where microbes associated with plants produce specialized metabolites, and the potential role of these molecules in mediating intramicrobiome interactions, is not well understood. Root nodules of legume plants are organs devoted to hosting symbiotic bacteria that fix atmospheric nitrogen and have recently been shown to harbor a relatively simple accessory microbiome containing members with the ability to produce specialized metabolites in vitro. On the basis of these observations, we sought to develop a model nodule microbiome system for evaluating specialized microbial metabolism in planta. Starting with an inoculum derived from field-grown Medicago sativa nodules, serial passaging through gnotobiotic nodules yielded a simplified accessory community composed of four members: Brevibacillus brevis, Paenibacillus sp., Pantoea agglomerans, and Pseudomonas sp. Some members of this community exhibited clear cooperation in planta, while others were antagonistic and capable of disrupting cooperation between other partners. Using matrix-assisted laser desorption ionization–imaging mass spectrometry, we found that metabolites associated with individual taxa had unique distributions, indicating that some members of the nodule community were spatially segregated. Finally, we identified two families of molecules produced by B. brevis in planta as the antibacterial tyrocidines and a novel set of gramicidin-type molecules, which we term the britacidins. Collectively, these results indicate that in addition to nitrogen fixation, legume root nodules are likely also sites of active antimicrobial production.

scholarly journals Bni5p, a Septin-Interacting Protein, Is Required for Normal Septin Function and Cytokinesis in Saccharomyces cerevisiae

2002 ◽  
Vol 22 (19) ◽  
pp. 6906-6920 ◽  
Author(s):  
Philip R. Lee ◽  
Sukgil Song ◽  
Hyeon-Su Ro ◽  
Chong J. Park ◽  
John Lippincott ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Localization ◽  
Growth Defect ◽  
Dependent Manner ◽  
Interacting Protein ◽  
Growth Defects ◽  
Bud Emergence ◽  
Bud Neck ◽  
And Function

ABSTRACT In the budding yeast Saccharomyces cerevisiae, the Cdc3p, Cdc10p, Cdc11p, Cdc12p, and Sep7p/Shs1p septins assemble early in the cell cycle in a ring that marks the future cytokinetic site. The septins appear to be major structural components of a set of filaments at the mother-bud neck and function as a scaffold for recruiting proteins involved in cytokinesis and other processes. We isolated a novel gene, BNI5, as a dosage suppressor of the cdc12-6 growth defect. Overexpression of BNI5 also suppressed the growth defects of cdc10-1, cdc11-6, and sep7Δ strains. Loss of BNI5 resulted in a cytokinesis defect, as evidenced by the formation of connected cells with shared cytoplasms, and deletion of BNI5 in a cdc3-6, cdc10-1, cdc11-6, cdc12-6, or sep7Δ mutant strain resulted in enhanced defects in septin localization and cytokinesis. Bni5p localizes to the mother-bud neck in a septin-dependent manner shortly after bud emergence and disappears from the neck approximately 2 to 3 min before spindle disassembly. Two-hybrid, in vitro binding, and protein-localization studies suggest that Bni5p interacts with the N-terminal domain of Cdc11p, which also appears to be sufficient for the localization of Cdc11p, its interaction with other septins, and other critical aspects of its function. Our data suggest that the Bni5p-septin interaction is important for septin ring stability and function, which is in turn critical for normal cytokinesis.

scholarly journals Experimental evolution can enhance benefits of rhizobia to novel legume hosts

2021 ◽  
Vol 288 (1951) ◽  
pp. 20210812
Author(s):  
Kenjiro W. Quides ◽  
Alexandra J. Weisberg ◽  
Jerry Trinh ◽  
Fathi Salaheldine ◽  
Paola Cardenas ◽  
...  
Keyword(s):  
Root Nodules ◽  
Lotus Japonicus ◽  
Nodule Development ◽  
Nodule Formation ◽  
In Planta ◽  
Genetic Changes ◽  
Reduced Costs ◽  
Full Factorial ◽  
Host Tissues

Legumes preferentially associate with and reward beneficial rhizobia in root nodules, but the processes by which rhizobia evolve to provide benefits to novel hosts remain poorly understood. Using cycles of in planta and in vitro evolution, we experimentally simulated lifestyles where rhizobia repeatedly interact with novel plant genotypes with which they initially provide negligible benefits. Using a full-factorial replicated design, we independently evolved two rhizobia strains in associations with each of two Lotus japonicus genotypes that vary in regulation of nodule formation. We evaluated phenotypic evolution of rhizobia by quantifying fitness, growth effects and histological features on hosts, and molecular evolution via genome resequencing. Rhizobia evolved enhanced host benefits and caused changes in nodule development in one of the four host–symbiont combinations, that appeared to be driven by reduced costs during symbiosis, rather than increased nitrogen fixation. Descendant populations included genetic changes that could alter rhizobial infection or proliferation in host tissues, but lack of evidence for fixation of these mutations weakens the results. Evolution of enhanced rhizobial benefits occurred only in a subset of experiments, suggesting a role for host–symbiont genotype interactions in mediating the evolution of enhanced benefits from symbionts.

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