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Paramasamy Gunasekaran - One of the best experts on this subject based on the ideXlab platform.
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evaluation of inseq to identify genes essential for pseudomonas aeruginosa pgpr2 corn Root Colonization
G3: Genes Genomes Genetics, 2019Co-Authors: Ramamoorthy Sivakumar, Paramasamy Gunasekaran, Jothi Ranjani, Udayakumar S Vishnu, Sathyanarayanan Jayashree, Gabriel L Lozano, Jessica Miles, Nichole A Broderick, Changhui Guan, Jo HandelsmanAbstract:The reciprocal interaction between rhizosphere bacteria and their plant hosts results in a complex battery of genetic and physiological responses. In this study, we used insertion sequencing (INSeq) to reveal the genetic determinants responsible for the fitness of Pseudomonas aeruginosa PGPR2 during Root Colonization. We generated a random transposon mutant library of Pseudomonas aeruginosa PGPR2 comprising 39,500 unique insertions and identified genes required for growth in culture and on corn Roots. A total of 108 genes were identified as contributing to the fitness of strain PGPR2 on Roots. The importance in Root Colonization of four genes identified in the INSeq screen was verified by constructing deletion mutants in the genes and testing them for the ability to colonize corn Roots singly or in competition with the wild type. All four mutants were affected in corn Root Colonization, displaying 5- to 100-fold reductions in populations in single inoculations, and all were outcompeted by the wild type by almost 100-fold after seven days on corn Roots in mixed inoculations of the wild type and mutant. The genes identified in the screen had homology to genes involved in amino acid catabolism, stress adaptation, detoxification, signal transduction, and transport. INSeq technology proved a successful tool to identify fitness factors in P. aeruginosa PGPR2 for Root Colonization.
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inactivation of the transcriptional regulator encoding gene sdia enhances rice Root Colonization and biofilm formation in enterobacter cloacae gs1
Journal of Bacteriology, 2013Co-Authors: Manoharan Shankar, Paramasivan Ponraj, Devaraj Illakkiam, Jeyaprakash Rajendhran, Paramasamy GunasekaranAbstract:ABSTRACT Enterobacter cloacae GS1 is a plant growth-promoting bacterium which colonizes rice Roots. In the rhizosphere environment, N-acyl homoserine lactone (NAHL)-like quorum-sensing signals are known to be produced by host plants and other microbial inhabitants. E. cloacae GS1 was unable to synthesize NAHL quorum-sensing signals but had the NAHL-dependent transcriptional regulator-encoding gene sdiA. This study was aimed at understanding the effects of SdiA and NAHL-dependent cross talk in rice Root Colonization by E. cloacae GS1. Pleiotropic effects of sdiA inactivation included substantial increases in Root Colonization and biofilm formation, suggesting a negative role for SdiA in bacterial adhesion. We provide evidence that sdiA inactivation leads to elevated levels of biosynthesis of curli, which is involved in cellular adhesion. Extraneous addition of NAHLs had a negative effect on Root Colonization and biofilm formation. However, the sdiA mutant of E. cloacae GS1 was insensitive to NAHLs, suggesting that this NAHL-induced inhibition of Root Colonization and biofilm formation is SdiA dependent. Therefore, it is proposed that NAHLs produced by both plant and microbes in the rice rhizosphere act as cross-kingdom and interspecies signals to negatively impact cellular adhesion and, thereby, Root Colonization in E. cloacae GS1.
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Root Colonization of a rice growth promoting strain of enterobacter cloacae
Journal of Basic Microbiology, 2011Co-Authors: Manoharan Shankar, Paramasivan Ponraj, Devaraj Ilakkiam, Paramasamy GunasekaranAbstract:Enterobacter cloacae GS1 was isolated by in-planta enrichment of a rice rhizoplane bacterial community. It displayed strong seed adherence ability (2.5 × 105 cfu/seed) and colonized rice Roots reaching up to 1.65 × 109 cfu/g of fresh Root weight in a gnotobiotic Root Colonization system. E. cloacae GS1 was motile, able to solubilize tricalcium phosphate, and produced indole acetic acid like substances (15 μg/ml). As an introduced bioinoculant in non-sterile soil, E. cloacae GS1 colonized rice Roots and significantly improved the fresh weight, Root length, shoot length, and nitrogen content in inoculated rice seedlings as compared to uninoculated controls. This isolate was tagged with green fluorescent protein and various stages of Root Colonization in gnotobiotic hydroponic environment and non-sterile soil environment were followed by fluorescence microscopy. Owing to its effective Root colonizing ability and growth promoting potential, Enterobacter cloacae GS1 is a promising symbiotic bioinoculant for rice. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Ben Lugtenberg - One of the best experts on this subject based on the ideXlab platform.
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Characterization of NADH dehydrogenases of Pseudomonas fluorescens WCS365 and their role in competitive Root Colonization.
Molecular Plant-microbe Interactions, 2002Co-Authors: Margarita M. Camacho Carvajal, André H. M. Wijfjes, Ine H. M. Mulders, Ben Lugtenberg, Guido V. BloembergAbstract:The excellent-Root-colonizing Pseudomonas fluorescens WCS365 was selected previously as the parental strain for the isolation of mutants impaired in Root Colonization. Transposon mutagenesis of WCS365 and testing for Root Colonization resulted in the isolation of mutant strain PCL1201, which is approximately 100-fold impaired in competitive tomato Root Colonization. In this manuscript, we provide evidence that shows that the lack of NADH dehydrogenase I, an enzyme of the aerobic respiratory chain encoded by the nuo operon, is responsible for the impaired Root-Colonization ability of PCL1201. The complete sequence of the nuo operon (ranging from nuoA to nuoN) of P. fluorescens WCS365 was identified, including the promoter region and a transcriptional terminator consensus sequence downstream of nuoN. It was shown biochemically that PCL1201 is lacking NADH dehydrogenase I activity. In addition, the presence and activity of a second NADH dehydrogenase, encoded by the ndh gene, was identified to our knowledge ...
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increased uptake of putrescine in the rhizosphere inhibits competitive Root Colonization by pseudomonas fluorescens strain wcs365
Molecular Plant-microbe Interactions, 2001Co-Authors: Irene Kuiper, Guido V. Bloemberg, Sadaf Noreen, Jane Thomasoates, Ben LugtenbergAbstract:Sequence analysis of the chromosomal Tn5lacZ flanking regions of the Pseudomonas fluorescens WCS365 competitive Root Colonization mutant PCL1206 showed that the Tn5lacZ is inserted between genes homologous to bioA and potF. The latter gene is the first gene of the potF1F2GHI operon, which codes for a putrescine transport system in Escherichia coli. The position of the Tn5lacZ suggests an effect on the expression of the pot operon. A mutation in the potF1 gene as constructed in PCL1270, however, had no effect on competitive Root Colonization. The rate of uptake of [1,4-14C]putrescine by cells of mutant PCL1206 appeared to be increased, whereas cells of strain PCL1270 were strongly impaired in the uptake of putrescine. Dansylation of tomato Root exudate and subsequent thin-layer chromatography showed the presence of a component with the same Rf value as dansyl-putrescine, which was identified as dansyl-putrescine by mass spectrometric analyses. Other polyamines such as spermine and spermidine were not detec...
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Root Colonization by phenazine 1 carboxamide producing bacterium pseudomonas chlororaphis pcl1391 is essential for biocontrol of tomato foot and Root rot
Molecular Plant-microbe Interactions, 2000Co-Authors: Thomas F C Chinawoeng, Guido V. Bloemberg, Ine H. M. Mulders, Linda C Dekkers, Ben LugtenbergAbstract:The phenazine-1-carboxamide-producing bacterium Pseudomonas chlororaphis PCL1391 controls tomato foot and Root rot caused by Fusarium oxysporum f. sp. radicis-lycopersici. To test whether Root Colonization is required for biocontrol, mutants impaired in the known Colonization traits motility, prototrophy for amino acids, or production of the site-specific recombinase, Sss/XerC were tested for their Root tip Colonization and biocontrol abilities. Upon tomato seedling inoculation, Colonization mutants of strain PCL1391 were impaired in Root tip Colonization in a gnotobiotic sand system and in potting soil. In addition, all mutants were impaired in their ability to control tomato foot and Root rot, despite the fact that they produce wild-type levels of phenazine-1-carboxamide, the antifungal metabolite previously shown to be required for biocontrol. These results show, for what we believe to be the first time, that Root Colonization plays a crucial role in biocontrol, presumably by providing a delivery syste...
Ruifu Zhang - One of the best experts on this subject based on the ideXlab platform.
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Bacillus velezensis Wall Teichoic Acids Are Required for Biofilm Formation and Root Colonization
Applied and Environmental Microbiology, 2019Co-Authors: Zhihui Xu, Huihui Zhang, Qirong Shen, Ruifu ZhangAbstract:ABSTRACT Rhizosphere Colonization by plant growth-promoting rhizobacteria (PGPR) along plant Roots facilitates the ability of PGPR to promote plant growth and health. Thus, an understanding of the molecular mechanisms of the Root Colonization process by plant-beneficial Bacillus strains is essential for the use of these strains in agriculture. Here, we observed that an sfp gene mutant of the plant growth-promoting rhizobacterium Bacillus velezensis SQR9 was unable to form normal biofilm architecture, and differential protein expression was observed by proteomic analysis. A minor wall teichoic acid (WTA) biosynthetic protein, GgaA, was decreased over 4-fold in the Δsfp mutant, and impairment of the ggaA gene postponed biofilm formation and decreased cucumber Root Colonization capabilities. In addition, we provide evidence that the major WTA biosynthetic enzyme GtaB is involved in both biofilm formation and Root Colonization. The deficiency in biofilm formation of the ΔgtaB mutant may be due to an absence of UDP-glucose, which is necessary for the synthesis of biofilm matrix exopolysaccharides (EPS). These observations provide insights into the Root Colonization process by a plant-beneficial Bacillus strain, which will help improve its application as a biofertilizer. IMPORTANCEBacillus velezensis is a Gram-positive plant-beneficial bacterium which is widely used in agriculture. Additionally, Bacillus spp. are some of the model organisms used in the study of biofilms, and as such, the molecular networks and regulation systems of biofilm formation are well characterized. However, the molecular processes involved in Root Colonization by plant-beneficial Bacillus strains remain largely unknown. Here, we showed that WTAs play important roles in the plant Root Colonization process. The loss of the gtaB gene affects the ability of B. velezensis SQR9 to sense plant polysaccharides, which are important environmental cues that trigger biofilm formation and Colonization in the rhizosphere. This knowledge provides new insights into the Bacillus Root Colonization process and can help improve our understanding of plant-rhizobacterium interactions.
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Comparative Proteomics Analysis of Bacillus amyloliquefaciens SQR9 Revealed the Key Proteins Involved in in Situ Root Colonization
Journal of Proteome Research, 2014Co-Authors: Zhihui Xu, Qirong Shen, Xingxing Li, Qing Li, Nan Zhang, Ruifu ZhangAbstract:Bacillus Amyloliquefaciens SQR9 is a well-investigated plant growth-promoting rhizobacteria with strong Root Colonization capability. To identify the key proteins involved in in situ Root Colonization and biofilm formation, the proteomic profiles of planktonic and Root colonized SQR9 cells were compared. A total of 755 proteins were identified, of which 78 and 95 proteins were significantly increased and deceased, respectively, when SQR9 was colonized on the Root. The proteins that were closely affiliated with the Root Colonization belonged to the functional categories of biocontrol, detoxification, biofilm formation, cell motility and chemotaxis, transport, and degradation of plant polysaccharides. A two-component system protein ResE was increased 100-fold when compared to the planktonic status; impairment of the resE gene postponed the formation of cell biofilm and decreased the Root Colonization capability, which may be regulated through the spo0A-sinI-yqxM pathway. The SQR9 proteomic data provide valu...
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enhanced Root Colonization and biocontrol activity of bacillus amyloliquefaciens sqr9 by abrb gene disruption
Applied Microbiology and Biotechnology, 2013Co-Authors: Jun Weng, Qirong Shen, Yang Wang, Juan Li, Ruifu ZhangAbstract:Root Colonization by antagonistic bacteria is a prerequisite for successful biological control, and the instability of Colonization under varying environmental conditions has accentuated the need to improve the Colonization activity. Root Colonization by Bacillus spp. is mainly determined by chemotaxis and biofilm formation, and both functions are negatively controlled by the global transcription regulator AbrB. Here, we disrupted the gene abrB in Bacillus amyloliquefaciens SQR9, which has been proven to be a promising biocontrol agent of cucumber and watermelon wilt disease. Chemotaxis, biofilm formation, and Colonization activities as well as biocontrol efficiency were measured and compared between the wild-type strain of SQR9 and the abrB mutant. The data presented in this article demonstrate that the Colonization and biocontrol activity of B. amyloliquefaciens SQR9 could be significantly improved by abrB gene disruption. The results offer a new strategy to enhance the biocontrol efficacy of B. amyloliquefaciens SQR9.
Qirong Shen - One of the best experts on this subject based on the ideXlab platform.
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Bacillus velezensis Wall Teichoic Acids Are Required for Biofilm Formation and Root Colonization
Applied and Environmental Microbiology, 2019Co-Authors: Zhihui Xu, Huihui Zhang, Qirong Shen, Ruifu ZhangAbstract:ABSTRACT Rhizosphere Colonization by plant growth-promoting rhizobacteria (PGPR) along plant Roots facilitates the ability of PGPR to promote plant growth and health. Thus, an understanding of the molecular mechanisms of the Root Colonization process by plant-beneficial Bacillus strains is essential for the use of these strains in agriculture. Here, we observed that an sfp gene mutant of the plant growth-promoting rhizobacterium Bacillus velezensis SQR9 was unable to form normal biofilm architecture, and differential protein expression was observed by proteomic analysis. A minor wall teichoic acid (WTA) biosynthetic protein, GgaA, was decreased over 4-fold in the Δsfp mutant, and impairment of the ggaA gene postponed biofilm formation and decreased cucumber Root Colonization capabilities. In addition, we provide evidence that the major WTA biosynthetic enzyme GtaB is involved in both biofilm formation and Root Colonization. The deficiency in biofilm formation of the ΔgtaB mutant may be due to an absence of UDP-glucose, which is necessary for the synthesis of biofilm matrix exopolysaccharides (EPS). These observations provide insights into the Root Colonization process by a plant-beneficial Bacillus strain, which will help improve its application as a biofertilizer. IMPORTANCEBacillus velezensis is a Gram-positive plant-beneficial bacterium which is widely used in agriculture. Additionally, Bacillus spp. are some of the model organisms used in the study of biofilms, and as such, the molecular networks and regulation systems of biofilm formation are well characterized. However, the molecular processes involved in Root Colonization by plant-beneficial Bacillus strains remain largely unknown. Here, we showed that WTAs play important roles in the plant Root Colonization process. The loss of the gtaB gene affects the ability of B. velezensis SQR9 to sense plant polysaccharides, which are important environmental cues that trigger biofilm formation and Colonization in the rhizosphere. This knowledge provides new insights into the Bacillus Root Colonization process and can help improve our understanding of plant-rhizobacterium interactions.
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organic acids from Root exudates of banana help Root Colonization of pgpr strain bacillus amyloliquefaciens njn 6
Scientific Reports, 2015Co-Authors: Jun Yuan, Nan Zhang, Qiwei Huang, Waseem Raza, Rong Li, Jorge M Vivanco, Qirong ShenAbstract:Organic acids from Root exudates of banana help Root Colonization of PGPR strain Bacillus amyloliquefaciens NJN-6
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Comparative Proteomics Analysis of Bacillus amyloliquefaciens SQR9 Revealed the Key Proteins Involved in in Situ Root Colonization
Journal of Proteome Research, 2014Co-Authors: Zhihui Xu, Qirong Shen, Xingxing Li, Qing Li, Nan Zhang, Ruifu ZhangAbstract:Bacillus Amyloliquefaciens SQR9 is a well-investigated plant growth-promoting rhizobacteria with strong Root Colonization capability. To identify the key proteins involved in in situ Root Colonization and biofilm formation, the proteomic profiles of planktonic and Root colonized SQR9 cells were compared. A total of 755 proteins were identified, of which 78 and 95 proteins were significantly increased and deceased, respectively, when SQR9 was colonized on the Root. The proteins that were closely affiliated with the Root Colonization belonged to the functional categories of biocontrol, detoxification, biofilm formation, cell motility and chemotaxis, transport, and degradation of plant polysaccharides. A two-component system protein ResE was increased 100-fold when compared to the planktonic status; impairment of the resE gene postponed the formation of cell biofilm and decreased the Root Colonization capability, which may be regulated through the spo0A-sinI-yqxM pathway. The SQR9 proteomic data provide valu...
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enhanced Root Colonization and biocontrol activity of bacillus amyloliquefaciens sqr9 by abrb gene disruption
Applied Microbiology and Biotechnology, 2013Co-Authors: Jun Weng, Qirong Shen, Yang Wang, Juan Li, Ruifu ZhangAbstract:Root Colonization by antagonistic bacteria is a prerequisite for successful biological control, and the instability of Colonization under varying environmental conditions has accentuated the need to improve the Colonization activity. Root Colonization by Bacillus spp. is mainly determined by chemotaxis and biofilm formation, and both functions are negatively controlled by the global transcription regulator AbrB. Here, we disrupted the gene abrB in Bacillus amyloliquefaciens SQR9, which has been proven to be a promising biocontrol agent of cucumber and watermelon wilt disease. Chemotaxis, biofilm formation, and Colonization activities as well as biocontrol efficiency were measured and compared between the wild-type strain of SQR9 and the abrB mutant. The data presented in this article demonstrate that the Colonization and biocontrol activity of B. amyloliquefaciens SQR9 could be significantly improved by abrB gene disruption. The results offer a new strategy to enhance the biocontrol efficacy of B. amyloliquefaciens SQR9.
Junichi Kato - One of the best experts on this subject based on the ideXlab platform.
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identification of pseudomonas fluorescens chemotaxis sensory proteins for malate succinate and fumarate and their involvement in Root Colonization
Microbes and Environments, 2014Co-Authors: Ayaka Komatsu, Takahisa Tajima, Yutaka Nakashimada, Junichi KatoAbstract:Pseudomonas fluorescens Pf0-1 exhibited chemotactic responses to l-malate, succinate, and fumarate. We constructed a plasmid library of 37 methyl-accepting chemotaxis protein (MCP) genes of P. fluorescens Pf0-1. To identify a MCP for l-malate, the plasmid library was screened using the PA2652 mutant of Pseudomonas aeruginosa PAO1, a mutant defective in chemotaxis to l-malate. The introduction of Pfl01_0728 and Pfl01_3768 genes restored the ability of the PA2652 mutant to respond to l-malate. The Pfl01_0728 and Pfl01_3768 double mutant of P. fluorescens Pf0-1 showed no response to l-malate or succinate, while the Pfl01_0728 single mutant did not respond to fumarate. These results indicated that Pfl01_0728 and Pfl01_3768 were the major MCPs for l-malate and succinate, and Pfl01_0728 was also a major MCP for fumarate. The Pfl01_0728 and Pfl01_3768 double mutant unexpectedly exhibited stronger responses toward the tomato Root exudate and amino acids such as proline, asparagine, methionine, and phenylalanine than those of the wild-type strain. The ctaA, ctaB, ctaC (genes of the major MCPs for amino acids), Pfl01_0728, and Pfl01_3768 quintuple mutant of P. fluorescens Pf0-1 was less competitive than the ctaA ctaB ctaC triple mutant in competitive Root Colonization, suggesting that chemotaxis to l-malate, succinate, and/or fumarate was involved in tomato Root Colonization by P. fluorescens Pf0-1.
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identification of chemotaxis sensory proteins for amino acids in pseudomonas fluorescens pf0 1 and their involvement in chemotaxis to tomato Root exudate and Root Colonization
Microbes and Environments, 2012Co-Authors: Ayaka Komatsu, Takahisa Tajima, Yutaka Nakashimada, Junichi KatoAbstract:Pseudomonas fluorescens Pf0-1 showed positive chemotactic responses toward 20 commonly-occurring l-amino acids. Genomic analysis revealed that P. fluorescens Pf0-1 possesses three genes (Pfl01_0124, Pfl01_0354, and Pfl01_4431) homologous to the Pseudomonas aeruginosa PAO1 pctA gene, which has been identified as a chemotaxis sensory protein for amino acids. When Pf01_4431, Pfl01_0124, and Pfl01_0354 were introduced into the pctA pctB pctC triple mutant of P. aeruginosa PAO1, a mutant defective in chemotaxis to amino acids, its transformants showed chemotactic responses to 18, 16, and one amino acid, respectively. This result suggests that Pf01_4431, Pfl01_0124, and Pfl01_0354 are chemotaxis sensory proteins for amino acids and their genes were designated ctaA, ctaB, and ctaC, respectively. The ctaA ctaB ctaC triple mutant of P. fluorescens Pf0-1 showed only weak responses to Cys and Pro but no responses to the other 18 amino acids, indicating that CtaA, CtaB, and CtaC are major chemotaxis sensory proteins in P. fluorescens Pf0-1. Tomato Root Colonization by P. fluorescens strains was analyzed by gnotobiotic competitive Root Colonization assay. It was found that ctaA ctaB ctaC mutant was less competitive than the wild-type strain, suggesting that chemotaxis to amino acids, major components of Root exudate, has an important role in Root Colonization by P. fluorescens Pf0-1. The ctaA ctaB ctaC triple mutant was more competitive than the cheA mutant of P. fluorescens Pf0-1, which is non-chemotactic, but motile. This result suggests that chemoattractants other than amino acids are also involved in Root Colonization by P. fluorescens Pf0-1.
