scholarly journals Effect of Clay Mineralogy on Iron Bioavailability and Rhizosphere Transcription of 2,4-Diacetylphloroglucinol Biosynthetic Genes in Biocontrol Pseudomonas protegens

2013 ◽  
Vol 26 (5) ◽  
pp. 566-574 ◽  
Author(s):  
Juliana Almario ◽  
Claire Prigent-Combaret ◽  
Daniel Muller ◽  
Yvan Moënne-Loccoz
Keyword(s):  
Root Rot ◽  
Molecular Mechanisms ◽  
Clay Mineralogy ◽  
Iron Bioavailability ◽  
Thielaviopsis Basicola ◽  
Synthetic Genes ◽  
Rot Disease ◽  
Number Of Cells ◽  
Made In

Pseudomonas strains producing 2,4-diacetylphloroglucinol (DAPG) can protect plants from soilborne phytopathogens and are considered the primary reason for suppressiveness of morainic Swiss soils to Thielaviopsis basicola-mediated black root-rot disease of tobacco, even though they also occur nearby in conducive sandstone soils. The underlying molecular mechanisms accounting for this discrepancy are not understood. In this study, we assessed the hypothesis that the presence of iron-rich vermiculite clay (dominant in suppressive soils) instead of illite (dominant in neighboring conducive soils) translates into higher levels of iron bioavailability and transcription of Pseudomonas DAPG synthetic genes in the tobacco rhizosphere. Rhizosphere monitoring of reporter gene systems pvd-inaZ and phlA-gfp in Pseudomonas protegens indicated that the level of iron bioavailability and the number of cells expressing phl genes (DAPG synthesis), respectively, were higher in vermiculitic than in illitic artificial soils. This was in accordance with the effect of iron on phlA-gfp expression in vitro and, indeed, iron addition to the illitic soil increased the number of cells expressing phlA-gfp. Similar findings were made in the presence of the pathogen T. basicola. Altogether, results substantiate the hypothesis that iron-releasing minerals may confer disease suppressiveness by modulating iron bioavailability in the rhizosphere and expression of biocontrol-relevant genes in antagonistic P. protegens.

scholarly journals Bacillus megaterium-Mediated Synthesis of Selenium Nanoparticles and Their Antifungal Activity against Rhizoctonia solani in Faba Bean Plants

2021 ◽  
Vol 7 (3) ◽  
pp. 195
Author(s):  
Amr H. Hashem ◽  
Amer M. Abdelaziz ◽  
Ahmed A. Askar ◽  
Hossam M. Fouda ◽  
Ahmed M. A. Khalil ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Vicia Faba ◽  
Root Rot ◽  
Antifungal Agents ◽  
Damping Off ◽  
Growth Promoters ◽  
Root Rot Disease ◽  
Rot Disease

Rhizoctonia root-rot disease causes severe economic losses in a wide range of crops, including Vicia faba worldwide. Currently, biosynthesized nanoparticles have become super-growth promoters as well as antifungal agents. In this study, biosynthesized selenium nanoparticles (Se-NPs) have been examined as growth promoters as well as antifungal agents against Rhizoctonia solani RCMB 031001 in vitro and in vivo. Se-NPs were synthesized biologically by Bacillus megaterium ATCC 55000 and characterized by using UV-Vis spectroscopy, XRD, dynamic light scattering (DLS), and transmission electron microscopy (TEM) imaging. TEM and DLS images showed that Se-NPs are mono-dispersed spheres with a mean diameter of 41.2 nm. Se-NPs improved healthy Vicia faba cv. Giza 716 seed germination, morphological, metabolic indicators, and yield. Furthermore, Se-NPs exhibited influential antifungal activity against R. solani in vitro as well as in vivo. Results revealed that minimum inhibition and minimum fungicidal concentrations of Se-NPs were 0.0625 and 1 mM, respectively. Moreover, Se-NPs were able to decrease the pre-and post-emergence of R. solani damping-off and minimize the severity of root rot disease. The most effective treatment method is found when soaking and spraying were used with each other followed by spraying and then soaking individually. Likewise, Se-NPs improve morphological and metabolic indicators and yield significantly compared with infected control. In conclusion, biosynthesized Se-NPs by B. megaterium ATCC 55000 are a promising and effective agent against R. solani damping-off and root rot diseases in Vicia faba as well as plant growth inducer.

Formation, translocation and resolution of Holliday junctions during homologous genetic recombination

1995 ◽  
Vol 347 (1319) ◽  
pp. 21-25 ◽  
Keyword(s):  
Molecular Mechanisms ◽  
Genetic Recombination ◽  
Holliday Junctions ◽  
The Novel ◽  
E Coli ◽  
The Past ◽  
Endonucleolytic Cleavage ◽  
Insight Into ◽  
Made In

Over the past three or four years, great strides have been made in our understanding of the proteins involved in recombination and the mechanisms by which recombinant molecules are formed. This review summarizes our current understanding of the process by focusing on recent studies of proteins involved in the later steps of recombination in bacteria. In particular, biochemical investigation of the in vitro properties of the E. coli RuvA, RuvB and RuvC proteins have provided our first insight into the novel molecular mechanisms by which Holliday junctions are moved along DNA and then resolved by endonucleolytic cleavage.

scholarly journals Response of the Biocontrol AgentPseudomonas pseudoalcaligenesAVO110 toRosellinia necatrixExudate

2018 ◽  
Vol 85 (3) ◽  
Author(s):  
Clara Pliego ◽  
José Ignacio Crespo-Gómez ◽  
Adrián Pintado ◽  
Isabel Pérez-Martínez ◽  
Antonio de Vicente ◽  
...  
Keyword(s):  
Root Rot ◽  
Molecular Mechanisms ◽  
Dna Helicase ◽  
Root Tip ◽  
Rosellinia Necatrix ◽  
Pseudomonas Pseudoalcaligenes ◽  
White Root Rot ◽  
Content Type ◽  
Root Rot Disease ◽  
Rot Disease

ABSTRACTThe rhizobacteriumPseudomonas pseudoalcaligenesAVO110, isolated by the enrichment of competitive avocado root tip colonizers, controls avocado white root rot disease caused byRosellinia necatrix. Here, we applied signature-tagged mutagenesis (STM) during the growth and survival of AVO110 in fungal exudate-containing medium with the goal of identifying the molecular mechanisms linked to the interaction of this bacterium withR. necatrix. A total of 26 STM mutants outcompeted by the parental strain in fungal exudate, but not in rich medium, were selected and namedgrowth-attenuatedmutants (GAMs). Twenty-one genes were identified as being required for this bacterial-fungal interaction, including membrane transporters, transcriptional regulators, and genes related to the metabolism of hydrocarbons, amino acids, fatty acids, and aromatic compounds. The bacterial traits identified here that are involved in the colonization of fungal hyphae include proteins involved in membrane maintenance (a dynamin-like protein and ColS) or cyclic-di-GMP signaling and chemotaxis. In addition, genes encoding a DNA helicase (recB) and a regulator of alginate production (algQ) were identified as being required for efficient colonization of the avocado rhizosphere.IMPORTANCEDiseases associated with fungal root invasion cause a significant loss of fruit tree production worldwide. The bacteriumPseudomonas pseudoalcaligenesAVO110 controls avocado white root rot disease caused byRosellinia necatrixby using mechanisms involving competition for nutrients and niches. Here, a functional genomics approach was conducted to identify the bacterial traits involved in the interaction with this fungal pathogen. Our results contribute to a better understanding of the multitrophic interactions established among bacterial biocontrol agents, the plant rhizosphere, and the mycelia of soilborne pathogens.

scholarly journals In vitro: stem cutting a simple technique for determination aggressive potential of fungal isolates causing root rot disease of grapevine

2020 ◽  
Vol 11 (1) ◽  
pp. 141-147
Author(s):  
El- Sayed Hussein Ziedan ◽  
Moataza Mahmoud Saad ◽  
Khames Ahmed Hemida ◽  
Mohamed Abd El- Aziz El -Naggar ◽  
Mostafa Helmy Mostafa ◽  
...  
Keyword(s):  
Root Rot ◽  
Simple Technique ◽  
Stem Cutting ◽  
Root Rot Disease ◽  
Fungal Isolates ◽  
Rot Disease

scholarly journals Transcriptome analysis of the fungal pathogen Rosellinia necatrix during infection of a susceptible avocado rootstock identifies potential mechanisms of pathogenesis

2019 ◽  
Author(s):  
Adela Zumaquero ◽  
Satoko Kanematsu ◽  
Hitoshi Nakayashiki ◽  
Antonio Matas ◽  
Elsa Martínez-Ferri ◽  
...  
Keyword(s):  
Transcriptome Analysis ◽  
Root Rot ◽  
Molecular Mechanisms ◽  
Plant Cell Wall ◽  
Infection Process ◽  
Rosellinia Necatrix ◽  
White Root Rot ◽  
Root Rot Disease ◽  
Host Interaction ◽  
Rot Disease

Abstract Background White root rot disease caused by Rosellinia necatrix is one of the most important threats affecting avocado productivity in tropical and subtropical climates. Control of this disease is complex and nowadays, lies in the use of physical and chemical methods, although none have proven to be fully effective. Detailed understanding of the molecular mechanisms underlying white root rot disease has the potential of aiding future developments in disease resistance and management. In this regard, this study used RNA-Seq technology to compare the transcriptomic profiles of R. necatrix during infection of susceptible avocado `Dusa´ roots with that obtained from the fungus cultured in rich medium. Results The transcriptomes from three biological replicates of R. necatrix colonizing avocado roots (RGA) and R. necatrix growing on potato dextrose agar media (RGPDA) were analyzed using Illumina sequencing. A total of 12,104 transcripts were obtained, among which 1,937 were differentially expressed genes (DEG), 137 exclusively expressed in RGA and 160 in RGPDA. During the root infection process, genes involved in the production of fungal toxins, detoxification and transport of toxic compounds, hormone biosynthesis, gene silencing and plant cell wall degradation were overexpressed. Interestingly, 24 out of the 137 contigs expressed only during R. necatrix growth on avocado roots, were predicted as candidate effector proteins (CEP) with a probability above 60%. The PHI (Pathogen Host Interaction) database revealed that three of the R. necatrix CEP showed homology with previously annotated effectors, already proven experimentally via pathogen-host interaction. Conclusions The analysis of the full-length transcriptome of R. necatrix during the infection process is suggesting that the success of this fungus to infect roots of diverse crops might be attributed to the production of different compounds which, singly or in combination, interfere with defense or signaling mechanisms shared among distinct plant families. The transcriptome analysis of R. necatrix during the infection process provides useful information and facilitates further research to a more in -depth understanding of the biology and virulence of this emergent pathogen. In turn, this will make possible to evolve novel strategies for white root rot management in avocado.

Antifungal activity of plant extracts against Embellisia astragali, the fungal causal agent of yellow dwarf and root-rot disease of standing milkvetch

2015 ◽  
Vol 66 (7) ◽  
pp. 735 ◽  
Author(s):  
Cuiyun Zeng ◽  
Xiaoyu Zhu ◽  
Zhen Cui ◽  
Yanzhong Li
Keyword(s):  
Antifungal Activity ◽  
Root Rot ◽  
Juglans Regia ◽  
Yellow Dwarf ◽  
Root Rot Disease ◽  
Ethanolic Extracts ◽  
Rot Disease ◽  
Causative Fungus ◽  
Saposhnikovia Divaricata

In an attempt to find biological fungicides, we screened 18 medicinal plants used in Chinese traditional medicine for their activity against Embellisia astragali, the causative fungus of yellow dwarf and root-rot disease in standing milkvetch (Astragalus adsurgens Pall.). The antifungal efficacy of ethanolic extracts of these plants was tested in vitro. Our results show that among the 18 plants tested, the ethanolic extracts of Saposhnikovia divaricata, Allium sativum and Juglans regia totally inhibited mycelial growth of E. astragali. These three extracts also significantly inhibited spore germination of E. astragali, with inhibition rates ranging from 86% to 88%. In addition, the same extract from the same plant part indicated the strongest antifungal activity against E. astragali, with a minimal inhibitory concentration value of 50 mg mL–1. These results demonstrate that plant-derived products have a high potential to control yellow dwarf and root-rot disease in standing milkvetch.

Impact of chitosan seed treatment of fenugreek for management of root rot disease caused by Fusarium solani under in vitro and in vivo conditions

3 Biotech ◽  
2021 ◽  
Vol 11 (6) ◽  
Author(s):  
Mahesh R. Ghule ◽  
Purushottam K. Ramteke ◽  
Sahadeo D. Ramteke ◽  
Prasad S. Kodre ◽  
Amruta Langote ◽  
...  
Keyword(s):  
Fusarium Solani ◽  
Root Rot ◽  
Seed Treatment ◽  
Root Rot Disease ◽  
Rot Disease
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