scholarly journals The Internal Glycine-Rich Motif and Cysteine Suppress Several Effects of the HpaGXooc Protein in Plants

2006 ◽  
Vol 96 (10) ◽  
pp. 1052-1059 ◽  
Author(s):  
Fengquan Liu ◽  
Hongxia Liu ◽  
Qin Jia ◽  
Xiaojing Wu ◽  
Xiaojing Guo ◽  
...  
Keyword(s):  
Plant Growth ◽  
Pseudomonas Syringae ◽  
Growth Promotion ◽  
Marker Genes ◽  
Pathogen Defense ◽  
Hypersensitive Cell Death ◽  
Tobacco Plants ◽  
Tomato Plants ◽  
Aerial Parts ◽  
Stimulate Plant Growth

HpaGXooc, produced by Xanthomonas oryzae pv. oryzicola, is a member of harpin group of proteins that stimulate plant growth, hypersensitive cell death (HCD), and pathogen defense. The protein contains two copies of the glycine-rich motif (GRM), a characteristic of harpins, and a cysteine, which is absent in other harpins. Genetic modification generated the pro-tein mutants HpaGXoocMG (MG) by deleting GRMs and HpaGXoocC47T (C47T) by replacing cysteine with threonine. When applied to tobacco plants, C47T and MG were 1.2- and 1.7-fold stronger, respectively, than HpaGXooc in inducing HCD, which occurred consistently with expression of the marker genes hin1 and hsr203. The proteins markedly alleviated infection of tobacco by Tobacco mosaic virus and Arabidopsis and tomato by Pseudomonas syringae. Treating tobacco plants with HpaGXooc, C47T, and MG decreased the viral infection by 58, 81, and 92%, respectively. In Arabidopsis and tomato plants treated with HpaGXooc, C47T, or MG, P. syringae multiplication was inhibited; bacterial population multiplied in 5 days in these plants were ca. 160-, 1,260-, or 15,860-fold smaller than that in control plants. So pathogen defense was induced in both plants. Defense-related genes Chia5, NPR1, and PR-1a were expressed consistently with resistance. In response to HpaGXooc, C47T, and MG, aerial parts and roots of tomato plants increased growth by 15 and 53%, 25 and 77%, and 46 and 106%, relative to controls. The expansin gene, EXP2, involved in the cell expansion and plant growth was expressed coordinately with plant growth promotion. These results suggest that the presence of GRM and cysteine in HpaGXooc represses the effects of the protein in plants.

Enhanced tomato plant growth in soil under reduced P supply through microbial inoculants and microbiome shifts

2019 ◽  
Vol 95 (9) ◽  
Author(s):  
Namis Eltlbany ◽  
Mohamed Baklawa ◽  
Guo-Chun Ding ◽  
Dinah Nassal ◽  
Nino Weber ◽  
...  
Keyword(s):  
Plant Growth ◽  
Root Growth ◽  
Growth Promotion ◽  
Bacterial Community Composition ◽  
Soil Microbial Communities ◽  
Rrna Gene ◽  
Pseudomonas Sp ◽  
Tomato Plants ◽  
Soil P ◽  
Bacterial Inoculants

ABSTRACT Soil microbial communities interact with roots, affecting plant growth and nutrient acquisition. In the present study, we aimed to decipher the effects of the inoculants Trichoderma harzianum T-22, Pseudomonas sp. DSMZ 13134, Bacillus amyloliquefaciens FZB42 or Pseudomonas sp. RU47 on the rhizosphere microbial community and their beneficial effects on tomato plants grown in moderately low phosphorous soil under greenhouse conditions. We analyzed the plant mass, inoculant colony forming units and rhizosphere communities on 15, 22, 29 and 43 days after sowing. Selective plating showed that the bacterial inoculants had a good rhizocompetence and accelerated shoot and root growth and nutrient accumulation. 16S rRNA gene fingerprints indicated changes in the rhizosphere bacterial community composition. Amplicon sequencing revealed that rhizosphere bacterial communities from plants treated with bacterial inoculants were more similar to each other and distinct from those of the control and the Trichoderma inoculated plants at harvest time, and numerous dynamic taxa were identified. In conclusion, likely both, inoculants and the rhizosphere microbiome shifts, stimulated early plant growth mainly by improved spatial acquisition of available nutrients via root growth promotion. At harvest, all tomato plants were P-deficient, suggesting a limited contribution of inoculants and the microbiome shifts to the solubilization of sparingly soluble soil P.

scholarly journals Protection of Tomato Seedlings against Infection by Pseudomonas syringae pv. Tomato by Using the Plant Growth-Promoting Bacterium Azospirillum brasilense

2002 ◽  
Vol 68 (6) ◽  
pp. 2637-2643 ◽  
Author(s):  
Yoav Bashan ◽  
Luz E. de-Bashan
Keyword(s):  
Plant Growth ◽  
Pseudomonas Syringae ◽  
Azospirillum Brasilense ◽  
Dry Weight ◽  
Tomato Plants ◽  
Bacterial Speck ◽  
Plant Growth Promoting ◽  
Bacterial Speck Disease ◽  
Growth Promoting ◽  
Mist Chamber

ABSTRACT Pseudomonas syringae pv. tomato, the causal agent of bacterial speck of tomato, and the plant growth-promoting bacterium Azospirillum brasilense were inoculated onto tomato plants, either alone, as a mixed culture, or consecutively. The population dynamics in the rhizosphere and foliage, the development of bacterial speck disease, and their effects on plant growth were monitored. When inoculated onto separate plants, the A. brasilense population in the rhizosphere of tomato plants was 2 orders of magnitude greater than the population of P. syringae pv. tomato (107 versus 105 CFU/g [dry weight] of root). Under mist chamber conditions, the leaf population of P. syringae pv. tomato was 1 order of magnitude greater than that of A. brasilense (107 versus 106 CFU/g [dry weight] of leaf). Inoculation of seeds with a mixed culture of the two bacterial strains resulted in a reduction of the pathogen population in the rhizosphere, an increase in the A. brasilense population, the prevention of bacterial speck disease development, and improved plant growth. Inoculation of leaves with the mixed bacterial culture under mist conditions significantly reduced the P. syringae pv. tomato population and significantly decreased disease severity. Challenge with P. syringae pv. tomato after A. brasilense was established in the leaves further reduced both the population of P. syringae pv. tomato and disease severity and significantly enhanced plant development. Both bacteria maintained a large population in the rhizosphere for 45 days when each was inoculated separately onto tomato seeds (105 to 106 CFU/g [dry weight] of root). However, P. syringae pv. tomato did not survive in the rhizosphere in the presence of A. brasilense. Foliar inoculation of A. brasilense after P. syringae pv. tomato was established on the leaves did not alleviate bacterial speck disease, and A. brasilense did not survive well in the phyllosphere under these conditions, even in a mist chamber. Several applications of a low concentration of buffered malic acid significantly enhanced the leaf population of A. brasilense (>108 CFU/g [dry weight] of leaf), decreased the population of P. syringae pv. tomato to almost undetectable levels, almost eliminated disease development, and improved plant growth to the level of uninoculated healthy control plants. Based on our results, we propose that A. brasilense be used in prevention programs to combat the foliar bacterial speck disease caused by P. syringae pv. tomato.

Colonization and persistence of a plant growth-promoting bacterium Pseudomonas fluorescens strain CS85, on roots of cotton seedlings

2004 ◽  
Vol 50 (7) ◽  
pp. 475-481 ◽  
Author(s):  
Chunxia Wang ◽  
Daoben Wang ◽  
Qi Zhou
Keyword(s):  
Plant Growth ◽  
Pseudomonas Fluorescens ◽  
Growth Promotion ◽  
Lateral Roots ◽  
Marker Genes ◽  
Original Strain ◽  
Plant Growth Promoting Bacteria ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Root Surfaces

Pseudomonas fluorescens CS85, which was previously isolated from the rhizosphere of cotton seedlings, acts as both a plant growth-promoting bacterium and a biocontrol agent against cotton pathogens, including Rhizoctonia solani, Colletotrichum gossypii, Fusarium oxysporum f sp. vasinfectum, and Verticillium dahliae. Strain CS85 was labeled separately with luxAB and gusA. The labeled strains were stably maintained and had high levels of expression of the marker genes, luxAB and gusA, after successive transfers on nonselective medium, long-term preservation, and after recovery from soil. The labeled strains displayed similar biocontrol characteristics (e.g., antibiosis, effects of growth -promotion and disease -control) to the original strain. The labeled strains colonized all surfaces of the young plant root zones, such as roots hairs and lateral roots, although the distribution of the labeled strains on the root surfaces was not uniform. Moreover, the population densities of the labeled strains on the root surface were stably maintained at high levels during the first 2 weeks of plant growth in the native soil, so that about 107–108 CFU/g root were detected, then decreased gradually. Nevertheless, approximately 106 CFU/g root of the labeled strains were observed on the root surfaces 35 d after planting.Key words: plant growth-promoting bacteria, luxAB, gusA, root colonization.

scholarly journals Bacterial Formulations in Induction of Resistance and Growth Promotion of Tomato Plants

2018 ◽  
Vol 10 (10) ◽  
pp. 493
Author(s):  
José R. M. Campos Neto ◽  
Rafael Ribeiro Chaves ◽  
Diogo Herison Silva Sardinha ◽  
Luiz Gustavo de Lima Melo ◽  
Antônia Alice Costa Rodrigues
Keyword(s):  
Plant Growth ◽  
Fusarium Wilt ◽  
Seed Treatment ◽  
Dry Matter ◽  
Growth Promotion ◽  
Systemic Resistance ◽  
Tomato Plants ◽  
Vigor Index ◽  
Promote Plant Growth ◽  
Induction Of Resistance

The objective of this work was to evaluate the effectiveness of seed treatment with fresh suspensions and powder formulations with Bacillus methylotrophicus to promote plant growth and induction of resistance against fusarium wilt (Fusarium oxysporum f. sp. lycopersici) in tomato plants under greenhouse conditions, verifying the occurrence of morphological and biochemical changes in the evaluated plants. Powder formulations based on Cassava (Manihot esculenta), Arrowroot (Maranta arundinacea) and sodium alginate containing Bacillus, in addition to the commercial product Quartz®, were used to microbiolize the tomato seeds of the cultivar Santa Cruz. The formulations promoted plant growth, with a seedling vigor index greater than 50% for all treatments containing B. mthylotrophicus, in addition to a significant increase in total dry matter. The treatments induced systemic resistance, controlling the fusarium wilt with a 75% reduction of the disease and activation of enzymes such as peroxidase and polyphenoloxidase, only β-1,3-glucanase presented less activity than controls (treatments without B. mthylotrophicus). Thus, the use of formulations containing Bacillus are efficient in promoting plant growth of tomato plants and in inducing resistance to the control of fusarium wilt.

scholarly journals Application of Seaweed Organic Components Increases Tolerance to Fe Deficiency in Tomato Plants

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 507
Author(s):  
Sandra Carrasco-Gil ◽  
Raúl Allende-Montalbán ◽  
Lourdes Hernández-Apaolaza ◽  
Juan J. Lucena
Keyword(s):  
Plant Growth ◽  
Organic Compounds ◽  
Growth Promotion ◽  
Abiotic Stress Tolerance ◽  
Nutrient Deficiency ◽  
Fe Deficiency ◽  
Tomato Plants ◽  
Beneficial Effects ◽  
Relevant Role ◽  
The Individual

The beneficial effects of seaweed extracts have been related to plant growth regulators present in seaweeds. However, algae extracts comprise other organic compounds such as phenols, mannitol, alginates, laminarins, and fucoidans that may have a relevant role regarding abiotic stress tolerance due to nutrient deficiency. Therefore, we evaluated the individual effect of these organic compounds in a range of concentrations on the mitigation of Fe deficiency in tomato plants. Germination and plant growth promotion, root morphology, chlorophyll content, and antioxidant activity were determined. Results showed that the lowest concentration of phenolics, laminarin, and fucose compounds contributed to increasing the tolerance to Fe deficiency in tomato plants.

scholarly journals Differential Response of Tomato Plants to the Application of Three Trichoderma Species When Evaluating the Control of Pseudomonas syringae Populations

Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 626 ◽  
Author(s):  
María E. Morán-Diez ◽  
Eduardo Tranque ◽  
Wagner Bettiol ◽  
Enrique Monte ◽  
Rosa Hermosa
Keyword(s):  
Pseudomonas Syringae ◽  
Molecular Mechanisms ◽  
Defense Responses ◽  
Marker Genes ◽  
Post Inoculation ◽  
Trichoderma Spp ◽  
Bacterial Populations ◽  
Oxidase Gene ◽  
Trichoderma Species ◽  
Tomato Plants

Trichoderma species are well known biocontrol agents that are able to induce responses in the host plants against an array of abiotic and biotic stresses. Here, we investigate, when applied to tomato seeds, the potential of Trichoderma strains belonging to three different species, T. parareesei T6, T. asperellum T25, and T. harzianum T34, to control the fully pathogenic strain Pseudomonas syringae pv. tomato (Pst) DC3000, able to produce the coronatine (COR) toxin, and the COR-deficient strain Pst DC3118 in tomato plants, and the molecular mechanisms by which the plant can modulate its systemic defense. Four-week old tomato plants, seed-inoculated, or not, with a Trichoderma strain, were infected, or not, with a Pst strain, and the changes in the expression of nine marker genes representative of salicylic acid (SA) (ICS1 and PAL5) and jasmonic acid (JA) (TomLoxC) biosynthesis, SA- (PR1b1), JA- (PINII and MYC2) and JA/Ethylene (ET)-dependent (ERF-A2) defense pathways, as well as the abscisic acid (ABA)-responsive gene AREB2 and the respiratory burst oxidase gene LERBOH1, were analyzed at 72 hours post-inoculation (hpi) with the bacteria. The significant increase obtained for bacterial population sizes in the leaves, disease index, and the upregulation of tomato genes related to SA, JA, ET and ABA in plants inoculated with Pst DC3000 compared with those obtained with Pst DC3118, confirmed the COR role as a virulence factor, and showed that both Pst and COR synergistically activate the JA- and SA-signaling defense responses, at least at 72 hpi. The three Trichoderma strains tested reduced the DC3118 levels to different extents and were able to control disease symptoms at the same rate. However, a minor protection (9.4%) against DC3000 was only achieved with T. asperellum T25. The gene deregulation detected in Trichoderma-treated plus Pst-inoculated tomato plants illustrates the complex system of a phytohormone-mediated signaling network that is affected by the pathogen and Trichoderma applications but also by their interaction. The expression changes for all nine genes analyzed, excepting LERBOH1, as well as the bacterial populations in the leaves were significantly affected by the interaction. Our results show that Trichoderma spp. are not adequate to control the disease caused by fully pathogenic Pst strains in tomato plants.

scholarly journals Diazotrophic bacteria from maize exhibit multifaceted plant growth promotion traits in multiple hosts

2020 ◽  
Author(s):  
Shawn M. Higdon ◽  
Tania Pozzo ◽  
Emily J. Tibbett ◽  
Colleen Chiu ◽  
Richard Jeannotte ◽  
...  
Keyword(s):  
Plant Growth ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Genomic Analysis ◽  
Comparative Genomic ◽  
Marker Genes ◽  
Diazotrophic Bacteria ◽  
In Planta ◽  
Pgp Traits

AbstractSierra Mixe maize is a geographically remote landrace variety grown on nitrogen-deficient fields in Oaxaca, Mexico that meets its nutritional requirements without synthetic fertilizer by associating with free-living diazotrophs comprising the microbiota of its aerial root mucilage. We selected nearly 500 diazotrophic bacteria isolated from Sierra Mixe maize mucilage and sequenced their genomes. Comparative genomic analysis demonstrated that isolates represented diverse genera and possessed multiple marker genes for mechanisms of direct plant growth promotion (PGP). In addition to nitrogen fixation, we examined deamination of 1-amino-1-cyclopropanecarboxylic acid, biosynthesis of indole-3-acetic acid, and phosphate solubilization. Implementing in vitro colorimetric assays revealed each isolate’s potential to confer the alternative PGP activities that corroborated genotype and pathway content. We examined the ability of mucilage diazotrophs to confer PGP by direct inoculation of clonally propagated potato plants in planta, which led to the identification of bio-stimulant candidates that were tested for PGP by inoculating a conventional maize variety. The results indicate that, while many diazotrophic isolates from Sierra Mixe maize possessed genotypes and in vitro phenotypes for targeted PGP traits, a subset of these organisms promoted the growth of potato and conventional maize using multiple promotion mechanisms.

scholarly journals Application of seaweed organic components increases tolerance to Fe deficiency in tomato plants

2019 ◽  
Author(s):  
Sandra Carrasco-Gil ◽  
Raúl Allende-Montalbán ◽  
Lourdes Hernández-Apaolaza ◽  
Juan José Lucena
Keyword(s):  
Plant Growth ◽  
Organic Compounds ◽  
Growth Promotion ◽  
Abiotic Stress Tolerance ◽  
Fe Deficiency ◽  
Tomato Plants ◽  
Hydroponic System ◽  
Beneficial Effects ◽  
Relevant Role ◽  
The Individual

AbstractThe beneficial effects of seaweed extracts have been related to plant growth regulators present in seaweeds. However, algae extracts comprise other organic compounds such as phenols, mannitol, alginates, laminarins and fucoidans that may have a relevant role regarding abiotic stress tolerance due to Fe deficiency. Therefore, we evaluated the individual effect of these organic compounds on the mitigation of Fe deficiency applying a range of concentrations (x1/10, x1, x10) in agar Petri dishes (in tomato seeds) and in the nutrient solution of a hydroponic system (tomato plants). Germination and plant growth promotion, root morphology, chlorophyll content and antioxidant activity were determined. Results showed that the lowest concentration x1/10 and phenolics, laminarin and fucose compounds contributed to increase the tolerance to Fe deficiency in tomato plants.

scholarly journals Genomic Analysis of the 1-Aminocyclopropane-1-Carboxylate Deaminase-Producing Pseudomonas thivervalensis SC5 Reveals Its Multifaceted Roles in Soil and in Beneficial Interactions With Plants

2021 ◽  
Vol 12 ◽  
Author(s):  
Francisco X. Nascimento ◽  
Paola Urón ◽  
Bernard R. Glick ◽  
Admir Giachini ◽  
Márcio J. Rossi
Keyword(s):  
Biological Control ◽  
Plant Growth ◽  
Pseudomonas Syringae ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Genomic Analysis ◽  
Acc Deaminase ◽  
Quorum Quenching ◽  
Cucumber Plant

Beneficial 1-aminocyclopropane-1-carboxylate (ACC) deaminase-producing bacteria promote plant growth and stress resistance, constituting a sustainable alternative to the excessive use of chemicals in agriculture. In this work, the increased plant growth promotion activity of the ACC deaminase-producing Pseudomonas thivervalensis SC5, its ability to limit the growth of phytopathogens, and the genomics behind these important properties are described in detail. P. thivervalensis SC5 displayed several active plant growth promotion traits and significantly increased cucumber plant growth and resistance against salt stress (100mmol/L NaCl) under greenhouse conditions. Strain SC5 also limited the in vitro growth of the pathogens Botrytis cinerea and Pseudomonas syringae DC3000 indicating active biological control activities. Comprehensive analysis revealed that P. thivervalensis SC5 genome is rich in genetic elements involved in nutrient acquisition (N, P, S, and Fe); osmotic stress tolerance (e.g., glycine-betaine, trehalose, and ectoine biosynthesis); motility, chemotaxis and attachment to plant tissues; root exudate metabolism including the modulation of plant phenolics (e.g., hydroxycinnamic acids), lignin, and flavonoids (e.g., quercetin); resistance against plant defenses (e.g., reactive oxygens species-ROS); plant hormone modulation (e.g., ethylene, auxins, cytokinins, and salicylic acid), and bacterial and fungal phytopathogen antagonistic traits (e.g., 2,4-diacetylphloroglucinol, HCN, a fragin-like non ribosomal peptide, bacteriocins, a lantipeptide, and quorum-quenching activities), bringing detailed insights into the action of this versatile plant-growth-promoting bacterium. Ultimately, the combination of both increased plant growth promotion/protection and biological control abilities makes P. thivervalensis SC5 a prime candidate for its development as a biofertilizer/biostimulant/biocontrol product. The genomic analysis of this bacterium brings new insights into the functioning of Pseudomonas and their role in beneficial plant-microbe interactions.

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