The Diazotroph as an Endophyte and How a Diazotroph Interacts with Its Plant Host

2021 ◽  
pp. 391-423
Author(s):  
Se-Chul Chun
Keyword(s):  
Plant Host

scholarly journals Environmental RNAi pathways in the two-spotted spider mite

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Mosharrof Mondal ◽  
Jacob Peter ◽  
Obrie Scarbrough ◽  
Alex Flynt
Keyword(s):  
Gene Expression ◽  
Small Rna ◽  
Spider Mite ◽  
Genetic Manipulation ◽  
Model Organisms ◽  
Rnai Pathway ◽  
Plant Host ◽  
Rnai Technology ◽  
Two Spotted Spider Mite ◽  
Multicellular Organisms

Abstract Background RNA interference (RNAi) regulates gene expression in most multicellular organisms through binding of small RNA effectors to target transcripts. Exploiting this process is a popular strategy for genetic manipulation and has applications that includes arthropod pest control. RNAi technologies are dependent on delivery method with the most convenient likely being feeding, which is effective in some animals while others are insensitive. The two-spotted spider mite, Tetranychus urticae, is prime candidate for developing RNAi approaches due to frequent occurrence of conventional pesticide resistance. Using a sequencing-based approach, the fate of ingested RNAs was explored to identify features and conditions that affect small RNA biogenesis from external sources to better inform RNAi design. Results Biochemical and sequencing approaches in conjunction with extensive computational assessment were used to evaluate metabolism of ingested RNAs in T. urticae. This chelicerae arthropod shows only modest response to oral RNAi and has biogenesis pathways distinct from model organisms. Processing of synthetic and plant host RNAs ingested during feeding were evaluated to identify active substrates for spider mite RNAi pathways. Through cataloging characteristics of biochemically purified RNA from these sources, trans-acting small RNAs could be distinguished from degradation fragments and their origins documented. Conclusions Using a strategy that delineates small RNA processing, we found many transcripts have the potential to enter spider mite RNAi pathways, however, trans-acting RNAs appear very unstable and rare. This suggests potential RNAi pathway substrates from ingested materials are mostly degraded and infrequently converted into regulators of gene expression. Spider mites infest a variety of plants, and it would be maladaptive to generate diverse gene regulators from dietary RNAs. This study provides a framework for assessing RNAi technology in organisms where genetic and biochemical tools are absent and benefit rationale design of RNAi triggers for T.urticae.

scholarly journals The Coevolution of Plants and Microbes Underpins Sustainable Agriculture

2021 ◽  
Vol 9 (5) ◽  
pp. 1036
Author(s):  
Dongmei Lyu ◽  
Levini A. Msimbira ◽  
Mahtab Nazari ◽  
Mohammed Antar ◽  
Antoine Pagé ◽  
...  
Keyword(s):  
Microbial Community ◽  
Plant Growth ◽  
Stress Resistance ◽  
Mycorrhizal Fungi ◽  
Plant Tissues ◽  
Terrestrial Plants ◽  
Plant Host ◽  
Symbiotic Relationships ◽  
Wide Range ◽  
Terrestrial Environments

Terrestrial plants evolution occurred in the presence of microbes, the phytomicrobiome. The rhizosphere microbial community is the most abundant and diverse subset of the phytomicrobiome and can include both beneficial and parasitic/pathogenic microbes. Prokaryotes of the phytomicrobiome have evolved relationships with plants that range from non-dependent interactions to dependent endosymbionts. The most extreme endosymbiotic examples are the chloroplasts and mitochondria, which have become organelles and integral parts of the plant, leading to some similarity in DNA sequence between plant tissues and cyanobacteria, the prokaryotic symbiont of ancestral plants. Microbes were associated with the precursors of land plants, green algae, and helped algae transition from aquatic to terrestrial environments. In the terrestrial setting the phytomicrobiome contributes to plant growth and development by (1) establishing symbiotic relationships between plant growth-promoting microbes, including rhizobacteria and mycorrhizal fungi, (2) conferring biotic stress resistance by producing antibiotic compounds, and (3) secreting microbe-to-plant signal compounds, such as phytohormones or their analogues, that regulate aspects of plant physiology, including stress resistance. As plants have evolved, they recruited microbes to assist in the adaptation to available growing environments. Microbes serve themselves by promoting plant growth, which in turn provides microbes with nutrition (root exudates, a source of reduced carbon) and a desirable habitat (the rhizosphere or within plant tissues). The outcome of this coevolution is the diverse and metabolically rich microbial community that now exists in the rhizosphere of terrestrial plants. The holobiont, the unit made up of the phytomicrobiome and the plant host, results from this wide range of coevolved relationships. We are just beginning to appreciate the many ways in which this complex and subtle coevolution acts in agricultural systems.

scholarly journals Endophytic Fungal Community of Huperzia serrata: Diversity and Relevance to the Production of Huperzine A by the Plant Host

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 892
Author(s):  
Lingli Cui ◽  
Hamza Armghan Noushahi ◽  
Yipeng Zhang ◽  
Jinxin Liu ◽  
Andreea Cosoveanu ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Fungal Community ◽  
Slow Growth ◽  
Specific Treatment ◽  
Huperzine A ◽  
Ionization Mass ◽  
Correlation Index ◽  
Plant Host ◽  
Huperzia Serrata

As the population ages globally, there seem to be more people with Alzheimer’s disease. Unfortunately, there is currently no specific treatment for the disease. At present, Huperzine A (HupA) is one of the best drugs used for the treatment of Alzheimer’s disease and has been used in clinical trials for several years in China. HupA was first separated from Huperzia serrata, a traditional medicinal herb that is used to cure fever, contusions, strains, hematuria, schizophrenia, and snakebite for several hundreds of years in China, and has been confirmed to have acetylcholinesterase inhibitory activity. With the very slow growth of H. serrata, resources are becoming too scarce to meet the need for clinical treatment. Some endophytic fungal strains that produce HupA were isolated from H. serrate in previous studies. In this article, the diversity of the endophytic fungal community within H. serrata was observed and the relevance to the production of HupA by the host plant was further analyzed. A total of 1167 strains were obtained from the leaves of H. serrata followed by the stems (1045) and roots (824). The richness as well as diversity of endophytic fungi within the leaf and stem were higher than in the root. The endophytic fungal community was similar within stems as well as in leaves at all taxonomic levels. The 11 genera (Derxomyces, Lophiostoma, Cyphellophora, Devriesia, Serendipita, Kurtzmanomyces, Mycosphaerella, Conoideocrella, Brevicellicium, Piskurozyma, and Trichomerium) were positively correlated with HupA content. The correlation index of Derxomyces with HupA contents displayed the highest value (CI = 0.92), whereas Trichomerium showed the lowest value (CI = 0.02). Through electrospray ionization mass spectrometry (ESI-MS), it was confirmed that the HS7-1 strain could produce HupA and the total alkaloid concentration was 3.7 ug/g. This study will enable us to screen and isolate the strain that can produce HupA and to figure out the correlation between endophytic fungal diversity with HupA content in different plant organs. This can provide new insights into the screening of strains that can produce HupA more effectively.

scholarly journals Paraburkholderia phymatum Homocitrate Synthase NifV Plays a Key Role for Nitrogenase Activity during Symbiosis with Papilionoids and in Free-Living Growth Conditions

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 952
Author(s):  
Paula Bellés-Sancho ◽  
Martina Lardi ◽  
Yilei Liu ◽  
Sebastian Hug ◽  
Marta Adriana Pinto-Carbó ◽  
...  
Keyword(s):  
Nitrogenase Activity ◽  
Root Nodules ◽  
Growth Conditions ◽  
Lysine Biosynthesis ◽  
Metabolome Analysis ◽  
Plant Host ◽  
Free Living ◽  
Bacterial Enzyme ◽  
Homocitrate Synthase ◽  
Iron Molybdenum Cofactor

Homocitrate is an essential component of the iron-molybdenum cofactor of nitrogenase, the bacterial enzyme that catalyzes the reduction of dinitrogen (N2) to ammonia. In nitrogen-fixing and nodulating alpha-rhizobia, homocitrate is usually provided to bacteroids in root nodules by their plant host. In contrast, non-nodulating free-living diazotrophs encode the homocitrate synthase (NifV) and reduce N2 in nitrogen-limiting free-living conditions. Paraburkholderia phymatum STM815 is a beta-rhizobial strain, which can enter symbiosis with a broad range of legumes, including papilionoids and mimosoids. In contrast to most alpha-rhizobia, which lack nifV, P. phymatum harbors a copy of nifV on its symbiotic plasmid. We show here that P. phymatum nifV is essential for nitrogenase activity both in root nodules of papilionoid plants and in free-living growth conditions. Notably, nifV was dispensable in nodules of Mimosa pudica despite the fact that the gene was highly expressed during symbiosis with all tested papilionoid and mimosoid plants. A metabolome analysis of papilionoid and mimosoid root nodules infected with the P. phymatum wild-type strain revealed that among the approximately 400 measured metabolites, homocitrate and other metabolites involved in lysine biosynthesis and degradation have accumulated in all plant nodules compared to uninfected roots, suggesting an important role of these metabolites during symbiosis.

Posttranslational Modification of Heterologous Human Therapeutics in Plant Host Expression Systems

2019 ◽  
pp. 145-169
Author(s):  
Ayyagari Archana ◽  
Lakshna Mahajan ◽  
Safikur Rahman ◽  
Rinki Minakshi
Keyword(s):  
Posttranslational Modification ◽  
Expression Systems ◽  
Plant Host

scholarly journals Setting the trap: cleaning behaviour ofCamponotus schmitziants increases long-term capture efficiency of their pitcher plant host,Nepenthes bicalcarata

2011 ◽  
Vol 26 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Daniel G. Thornham ◽  
Joanna M. Smith ◽  
T. Ulmar Grafe ◽  
Walter Federle
Keyword(s):  
Capture Efficiency ◽  
Plant Host ◽  
Pitcher Plant ◽  
Cleaning Behaviour

scholarly journals Temporal niche differentiation of parasites sharing the same plant host: oak powdery mildew as a case study

Ecosphere ◽  
2016 ◽  
Vol 7 (11) ◽  
Author(s):  
Frédéric M. Hamelin ◽  
Anne Bisson ◽  
Marie‐Laure Desprez‐Loustau ◽  
Frédéric Fabre ◽  
Ludovic Mailleret
Keyword(s):  
Powdery Mildew ◽  
Niche Differentiation ◽  
Plant Host ◽  
Temporal Niche ◽  
Temporal Niche Differentiation

scholarly journals Evidence of gene nucleotide composition favoring replication and growth in a fastidious plant pathogen

2021 ◽  
Author(s):  
Andreina I Castillo ◽  
Rodrigo P P Almeida
Keyword(s):  
Plant Pathogen ◽  
Geographic Origin ◽  
Gc Content ◽  
Nucleotide Composition ◽  
Plant Host ◽  
Mixed Effect ◽  
Genomic Changes ◽  
Evolutionary Forces ◽  
Multiple Variables ◽  
Vector Borne

Abstract Nucleotide composition (GC content) varies across bacteria species, genome regions, and specific genes. In Xylella fastidiosa, a vector-borne fastidious plant pathogen infecting multiple crops, GC content ranges between ∼51-52%; however, these values were gathered using limited genomic data. We evaluated GC content variations across X. fastidiosa subspecies fastidiosa (N = 194), subsp. pauca (N = 107), and subsp. multiplex (N = 39). Genomes were classified based on plant host and geographic origin; individual genes within each genome were classified based on gene function, strand, length, ortholog group, Core vs. Accessory, and Recombinant vs. Non-recombinant. GC content was calculated for each gene within each evaluated genome. The effects of genome and gene level variables were evaluated with a mixed effect ANOVA, and the marginal-GC content was calculated for each gene. Also, the correlation between gene-specific GC content vs. natural selection (dN/dS) and recombination/mutation (r/m) was estimated. Our analyses show that intra-genomic changes in nucleotide composition in X. fastidiosa are small and influenced by multiple variables. Higher AT-richness is observed in genes involved in replication and translation, and genes in the leading strand. In addition, we observed a negative correlation between high-AT and dN/dS in subsp. pauca. The relationship between recombination and GC content varied between core and accessory genes. We hypothesize that distinct evolutionary forces and energetic constraints both drive and limit these small variations in nucleotide composition.

scholarly journals What the Wild Things Do: Mechanisms of Plant Host Manipulation by Bacterial Type III-Secreted Effector Proteins

2021 ◽  
Vol 9 (5) ◽  
pp. 1029
Author(s):  
Karl J. Schreiber ◽  
Ilea J. Chau-Ly ◽  
Jennifer D. Lewis
Keyword(s):  
Pseudomonas Syringae ◽  
Structural Data ◽  
Enzymatic Activities ◽  
Effector Proteins ◽  
Host Recognition ◽  
Plant Host ◽  
Type Iii ◽  
Xanthomonas Species ◽  
Pathogen Fitness ◽  
Enzymatic Mechanisms

Phytopathogenic bacteria possess an arsenal of effector proteins that enable them to subvert host recognition and manipulate the host to promote pathogen fitness. The type III secretion system (T3SS) delivers type III-secreted effector proteins (T3SEs) from bacterial pathogens such as Pseudomonas syringae, Ralstonia solanacearum, and various Xanthomonas species. These T3SEs interact with and modify a range of intracellular host targets to alter their activity and thereby attenuate host immune signaling. Pathogens have evolved T3SEs with diverse biochemical activities, which can be difficult to predict in the absence of structural data. Interestingly, several T3SEs are activated following injection into the host cell. Here, we review T3SEs with documented enzymatic activities, as well as T3SEs that facilitate virulence-promoting processes either indirectly or through non-enzymatic mechanisms. We discuss the mechanisms by which T3SEs are activated in the cell, as well as how T3SEs modify host targets to promote virulence or trigger immunity. These mechanisms may suggest common enzymatic activities and convergent targets that could be manipulated to protect crop plants from infection.

Functional analysis of three AHL autoinducer synthase genes in Mesorhizobium loti reveals the important role of quorum sensing in symbiotic nodulation

2009 ◽  
Vol 55 (2) ◽  
pp. 210-214 ◽  
Author(s):  
Menghua Yang ◽  
Kejing Sun ◽  
Lei Zhou ◽  
Ruifu Yang ◽  
Zengtao Zhong ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Homoserine Lactone ◽  
Culture Conditions ◽  
Native Plant ◽  
Plant Host ◽  
Mesorhizobium Loti ◽  
Sensing Systems ◽  
Regulatory Circuits ◽  
Legume Symbiosis ◽  
Successful Establishment

One of the most important signal transduction pathways in bacteria, quorum sensing, is involved in many regulatory circuits in rhizobia, especially in the control of communication between rhizobia and their plant hosts. In this study, we identified 3 autoinducer synthase genes — mrlI1, mrlI2, and mrlI3 — in Mesorhizobium loti NZP 2213. We found that MrlI1 and MrlI2 could synthesize distinct N-acyl homoserine lactone (AHL) autoinducers in rich medium cultures, and the expression of mrlI1 was shown to be growth-phase-dependent. MrlI3 did not produce any detectable AHL molecules under the culture conditions tested. To investigate whether these AHL synthases affect nodulation, we examined the nodulation of AHL-deficient mutants on their native plant host Lotus corniculatus and found that the efficiency of nodulation of bacteria with mutations of any of these 3 synthase genes was reduced, suggesting that quorum sensing systems in M. loti may play an important role in successful establishment of rhizobium–legume symbiosis.

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