Antagonistic potential of some bacterial strains against Xanthomonas campestris, the cause of bacterial blight in Hordeum vulgare

Bacterial blight disease due to Xanthomonas campestris pv. translucens results in yield losses in barley, Hordeum vulgare L., especially in warm climates. Bio-based bactericides represent a safe alternative to harmful chemicals for controlling a wide range of phytopathogens. The bacterial strains (Brevibacterium linens, Bacillus subtilis, B. thuringiensis) were tested as antagonistic potential against X. campestris disease in barley seedlings. Antagonists were applied as seed biopriming and soil drench in X. campestris infested soil. Soil-drenching treatment was more efficient than the biopriming application. A significant increase in shoot length with a clear decrease in seed germination was recorded. Fresh and dry weights of shoot and root lengths of the treated plants were markedly improved. The remarkable antagonistic activity of B. linens, B. subtilis, and B. thuringiensis against X. campestris could be attributed to the capability to produce bioactive molecules that can trigger systemic resistance in the infected seedlings.

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Differential Pathogenicity of Xanthomonas campestris pv. phaseoli and X. fuscans subsp. fuscans Strains on Bean Genotypes with Common Blight Resistance

Plant Disease ◽

10.1094/pdis-92-4-0546 ◽

2008 ◽

Vol 92 (4) ◽

pp. 546-554 ◽

Cited By ~ 23

Author(s):

N. Mutlu ◽

A. K. Vidaver ◽

D. P. Coyne ◽

J. R. Steadman ◽

P. A. Lambrecht ◽

...

Keyword(s):

Common Bean ◽

Bacterial Blight ◽

Xanthomonas Campestris ◽

South American ◽

Bacterial Strains ◽

Genetic Changes ◽

Germplasm Screening ◽

Lack Of Information ◽

Pathogenic Variation ◽

The Common

Both the common bacterial blight (CBB) pathogen (Xanthomonas campestris pv. phaseoli) and X. fuscans subsp. fuscans, agent of fuscous blight, cause indistinguishable symptoms in common bean, Phaseolus vulgaris. Yield losses can exceed 40%. Lack of information about the specificity between X. campestris pv. phaseoli strains and major quantitative trait loci (QTL) or alleles conferring resistance makes the task of identifying genetic changes in host–pathogen interactions and the grouping of bacterial strains difficult. This, in turn, affects the choice of pathogen isolates used for germplasm screening and complicates breeding for CBB resistance. Common bean host genotypes carrying various sources and levels of resistance to CBB were screened with 69 X. campestris pv. phaseoli and 15 X. fuscans subsp. fuscans strains from around the world. Differential pathogenicity of the CBB pathogen was identified on the 12 selected bean genotypes. The X. fuscans subsp. fuscans strains showed greater pathogenicity than X. campestris pv. phaseoli strains having the same origin. African strains were most pathogenic. The largest variation in pathogenicity came from X. campestris pv. phaseoli strains that originated in Caribbean and South American countries. Pathogenic variation was greater within X. campestris pv. phaseoli than within X. fuscans subsp. fuscans strains. Implications for breeding for CBB resistance are discussed.

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Screening of plant growth promoting bacteria associated with barley plants (Hordeum vulgare L.) cultivated in South Brazil

Biota Neotropica ◽

10.1590/1676-06032015010514 ◽

2015 ◽

Vol 15 (2) ◽

Cited By ~ 6

Author(s):

Andress P. Pontes ◽

Rocheli de Souza ◽

Camille E. Granada ◽

Luciane M.P. Passaglia

Keyword(s):

Hordeum Vulgare ◽

Plant Growth ◽

Tricalcium Phosphate ◽

Future Application ◽

Rrna Gene ◽

Plant Growth Promoting Bacteria ◽

Bacterial Strains ◽

Hordeum Vulgare L ◽

Plant Growth Promoting ◽

Growth Promoting

The occurrence of associations between bacteria and plant roots may be beneficial, neutral or detrimental. Plant growth promoting (PGP) bacteria form a heterogeneous group of beneficial microorganisms that can be found in the rhizosphere, the root surfaces or in association with host plant. The aim of this study was to isolate and characterize PGP bacteria associated to barley plants (Hordeum vulgare L.) aiming a future application as agricultural inoculant. One hundred and sixty bacterial strains were isolated from roots or rhizospheric soil of barley based on their growth in nitrogen-free selective media. They were evaluated for their ability to produce indolic compounds (ICs) and siderophores, and to solubilize tricalcium phosphate inin vitro assays. Most of them (74%) were able to synthesize ICs in the presence of the precursor L-tryptophan, while 57% of the isolates produced siderophores in Fe-limited liquid medium, and 17% were able to solubilize tricalcium phosphate. Thirty-two isolates possessing different PGP characteristics were identified by partial sequencing of their 16S rRNA gene. Strains belonging to Cedecea andMicrobacterium genera promoted the growth of barley plants in insoluble phosphate conditions, indicating that these bacteria could be used as bioinoculants contributing to decrease the amount of fertilizers applied in barley crops.

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Nigritanine as a New Potential Antimicrobial Alkaloid for the Treatment of Staphylococcus aureus-Induced Infections

Toxins ◽

10.3390/toxins11090511 ◽

2019 ◽

Vol 11 (9) ◽

pp. 511 ◽

Cited By ~ 17

Author(s):

Bruno Casciaro ◽

Andrea Calcaterra ◽

Floriana Cappiello ◽

Mattia Mori ◽

Maria Loffredo ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Activity ◽

Antibacterial Activity ◽

Biological Activities ◽

Human Keratinocytes ◽

Chemical Diversity ◽

Bioactive Molecules ◽

Bacterial Strains ◽

Wide Range

Staphylococcus aureus is a major human pathogen causing a wide range of nosocomial infections including pulmonary, urinary, and skin infections. Notably, the emergence of bacterial strains resistant to conventional antibiotics has prompted researchers to find new compounds capable of killing these pathogens. Nature is undoubtedly an invaluable source of bioactive molecules characterized by an ample chemical diversity. They can act as unique platform providing new scaffolds for further chemical modifications in order to obtain compounds with optimized biological activity. A class of natural compounds with a variety of biological activities is represented by alkaloids, important secondary metabolites produced by a large number of organisms including bacteria, fungi, plants, and animals. In this work, starting from the screening of 39 alkaloids retrieved from a unique in-house library, we identified a heterodimer β-carboline alkaloid, nigritanine, with a potent anti-Staphylococcus action. Nigritanine, isolated from Strychnos nigritana, was characterized for its antimicrobial activity against a reference and three clinical isolates of S. aureus. Its potential cytotoxicity was also evaluated at short and long term against mammalian red blood cells and human keratinocytes, respectively. Nigritanine showed a remarkable antimicrobial activity (minimum inhibitory concentration of 128 µM) without being toxic in vitro to both tested cells. The analysis of the antibacterial activity related to the nigritanine scaffold furnished new insights in the structure–activity relationships (SARs) of β-carboline, confirming that dimerization improves its antibacterial activity. Taking into account these interesting results, nigritanine can be considered as a promising candidate for the development of new antimicrobial molecules for the treatment of S. aureus-induced infections.

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Induction of Systemic Resistance by Biocontrol Agents against Bacterial Blight of Cotton Caused by Xanthomonas campestris pv. malvacearum

International Journal of Phytopathology ◽

10.33687/phytopath.002.01.0071 ◽

2013 ◽

Vol 2 (1) ◽

pp. 59-69

Author(s):

Vinay B. Raghavendra ◽

Lokesh Siddalingaiah ◽

Nagesh K. Sugunachar ◽

Chandra Nayak ◽

Niranjana S. Ramachandrappa

Keyword(s):

Defense Mechanisms ◽

Bacterial Blight ◽

Seed Treatment ◽

Xanthomonas Campestris ◽

Growth Parameters ◽

Direct Action ◽

Systemic Resistance ◽

Challenge Inoculation ◽

Stimulate Plant Growth ◽

Blight Disease

Bioagents such as Trichoderma harzianum, Pseudomonas fluorescens and Bacillus subtilis were isolated from cotton rhizosphere soil and tested individually for their effectiveness in controlling bacterial blight of cotton caused by Xanthomonas campestris pv. malvacearum (Xcm). Talc based formulations were prepared and used for seed treatment at different concentrations for assessing their ability to stimulate plant growth and to control bacterial blight disease. Among bioagents, P. fluorescens and T. harzianum proved to be effective in controlling disease under field conditions. Other than direct action, these bioagents triggered the defense related enzymes involved in synthesis of phenols. Higher activity of peroxidase, phenylalanine ammonia-lyase, polyphenol oxidase and b-1,3-glucanase was observed in P. fluorescens and T. harzianum treated cotton plants after challenge inoculation with Xcm. Seed treatment with these bioagents enhanced the seed germination and growth parameters against blight disease and they also induced systemic resistance in plant for defense mechanisms.

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Application of Rhizobacteria for Induction of Systemic Resistance to Bacterial Blight of Cotton Caused by Xanthomonas Campestris PV. Malvacearum Using Fluorescent Pseudomonads of Rhizosphere

Journal of Plant Protection Research ◽

10.2478/v10045-009-0066-5 ◽

2009 ◽

Vol 49 (4) ◽

Cited By ~ 2

Author(s):

Vahid Fallahzadeh ◽

Masoud Ahmadzadeh ◽

Alireza Marefat ◽

Keivan Ghazanfary

Keyword(s):

Bacterial Blight ◽

Xanthomonas Campestris ◽

Fluorescent Pseudomonads ◽

Systemic Resistance

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Yield Performance of Barley Hybrids (Hordeum vulgare L.) under Drought stress and non-stressed Conditions

passer ◽

10.24271/psr.20 ◽

2019 ◽

Vol 3 (1) ◽

pp. 107-113

Author(s):

Yadgar Mahmood ◽

Halgurd Nasraden Hassan ◽

Masood Saber Mohammed

Keyword(s):

Drought Stress ◽

Hordeum Vulgare ◽

Grain Yield ◽

Plant Height ◽

Harvest Index ◽

Dry Matter ◽

Growth And Yield ◽

Yield Reduction ◽

Hordeum Vulgare L ◽

Wide Range

This study was carried out at the experiment field, Kalar Technical Institute, Garmian Region in two growing seasons of 2016-2017 and 2017-2018 in order to evaluate the growth and yield potentials of barley under water stressed using hybrids as a source of wide range of genotypic variations. Therefore, five F2 barley hybrids (Hordeum vulgare L.) were screened for grain yield, biomass dry matter, plant height and harvest index under irrigated and drought conditions. Results showed that there was no effect of drought on grain yield (P>0.05) in 2017, while significantly reduced yield in 2018 and across-year mean (P-2 (3//14) under irrigated condition, and 267.8 (3//5) to 302.3 g m-2 (3//4) under unirrigated condition (P=0.001), biomass dry matter was ranged from 1099.1 (3//1) to 1370.5 g m-2 (3//14) under irrigated condition, and 892.6 (3//1) to 1153.9 g m-2 (3//14) under unirrigated condition (P=0.05), and harvest index were from 25.1 (3//14) to 28.0 (3//1) under irrigated conditions, and 25.9 (3//14) to 31.2 (3//1) under unirrigated conditions (P=0.04). Regression analysis, averaging over years, showed a positive relationship between grain yield and biomass under irrigated (R2=0.76; P=0.05), despite that, any positive relation was not found under unirrigated conditions (R2=0.43; P=0.23) due to post-anthesis drought stress. A strong relationship was also found between plant height and biomass dry matter under both irrigated (R2=0.89; P=0.02) and unirrigated (R2=0.97; P=0.003) conditions due to the high contribution of plant height in increasing plant biomass. It is concluded that genotypes had different response to drought due to their genetic diversity, and relatively low impact of water stress was appeared on growth and grain yield of barley in this semi-arid region compared to worldwide expected range of yield reduction.

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Above- and below-ground net primary production of four barley (Hordeum vulgare L.) cultivars in western Canada

Canadian Journal of Plant Science ◽

10.4141/cjps92-138 ◽

1992 ◽

Vol 72 (4) ◽

pp. 1131-1140 ◽

Cited By ~ 22

Author(s):

J. G. Xu ◽

N. G. Juma

Keyword(s):

Organic Matter ◽

Hordeum Vulgare ◽

Primary Production ◽

Net Primary Production ◽

Root Mass ◽

Hordeum Vulgare L ◽

Ripening Stages ◽

Wide Range ◽

Below Ground ◽

Shoot Mass

Information on above- and below-ground primary production for a wide range of agro-ecosystems is needed. The objective of this study was to quantify the shoot and root mass, shoot mass/root mass ratios, and root lengths of four barley (Hordeum vulgare L.) cultivars (Abee, Bonanza, Harrington and Samson) grown in a Black Chernozem in north-central Alberta. The cultivars were grown using a randomized complete block design with three replicates and were sampled at the tillering, stem-extension, heading, and ripening stages. Root mass and root lengths from soil cores were measured. The results showed that (1) shoot mass and root mass of Harrington and Bonanza were not different from those of Abee and Samson, but those of Abee were significantly greater than those of Samson, indicating that the below-ground input of organic matter could be a function of specific cultivar; (2) root mass increased rapidly until the heading stage, and shoot mass increased at a higher rate than roots between the heading and ripening stages, producing a widening of shoot/root ratios with time; and (3) decomposition of very small roots may have contributed to a more rapid decrease in root length than in root mass after the heading stage.Key words: Barley (Hordeum vulgare L.) cultivars, Typic Cryoboroll, root mass, root lengths, shoot/root ratio, soil organic matter

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Ultrastructure and Senescence in an Achloroplastic Mutant of Hordeum vulgare L. cv. Dyan

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100124628 ◽

1992 ◽

Vol 50 (1) ◽

pp. 844-845

Author(s):

R.H.M. Cross ◽

C.E.J. Botha ◽

A.K. Cowan ◽

B.J. Hartley

Keyword(s):

Cell Wall ◽

Hordeum Vulgare ◽

Leaf Tissue ◽

Ultrastructural Changes ◽

Hordeum Vulgare L ◽

Mesophyll Cells ◽

Lethal Mutant ◽

Cytoplasmic Matrix ◽

Close Proximity ◽

Pinocytotic Vesicles

Senescence is an ordered degenerative process leading to death of individual cells, organs and organisms. The detection of a conditional lethal mutant (achloroplastic) of Hordeum vulgare has enabled us to investigate ultrastructural changes occurring in leaf tissue during foliar senescence.Examination of the tonoplast structure in six and 14 day-old mutant tissue revealed a progressive degeneration and disappearance of the membrane, apparently starting by day six in the vicinity of the mitochondria associated with the degenerating proplastid (Fig. 1.) where neither of the plastid membrane leaflets is evident (arrows, Fig. 1.). At this stage there was evidence that the mitochondrial membranes were undergoing retrogressive changes, coupled with disorganization of cristae (Fig. 2.). Proplastids (P) lack definitive prolamellar bodies. The cytoplasmic matrix is largely agranular, with few endoplasmic reticulum (ER) cisternae or polyribosomal aggregates. Interestingly, large numbers of actively-budding dictysomes, associated with pinocytotic vesicles, were observed in close proximity to the plasmalemma of mesophyll cells (Fig. 3.). By day 14 however, mesophyll cells showed almost complete breakdown of subcellular organelle structure (Fig. 4.), and further evidence for the breakdown of the tonoplast. The final stage of senescence is characterized by the solubilization of the cell wall due to expression and activity of polygalacturonase and/or cellulose. The presence of dictyosomes with associated pinocytotic vesicles formed from the mature face, in close proximity to both the plasmalemma and the cell wall, would appear to support the model proposed by Christopherson for the secretion of cellulase. This pathway of synthesis is typical for secretory glycoproteins.

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