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Roberts DP, Selmer K, Lupitskyy R, Rice C, Buyer JS, Maul JE, Lakshman DK, DeSouza J. Seed treatment with prodigiosin controls damping-off of cucumber caused by Pythium ultimum. AMB Express 2021; 11:10. [PMID: 33409670 PMCID: PMC7788126 DOI: 10.1186/s13568-020-01169-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 12/15/2020] [Indexed: 11/22/2022] Open
Abstract
Ethanol extract of cell mass of Serratia marcescens strain N4-5, when applied as a treatment to cucumber seed, has been shown to provide control of the oomycete soil-borne plant pathogen Pythium ultimum equivalent to that provided by a seed-treatment chemical pesticide in some soils. Two dominant compounds in this extract, prodigiosin and the serratamolide serrawetin W1, were identified based on mass and collision induced dissociation mass fragmentation spectra. An additional four compounds with M+H+ masses (487, 541, 543, and 571) consistent with serratamolides reported in the literature were also detected. Several other compounds with M+H+ masses of 488, 536, 684, 834, 906, and 908 m/z were detected in this ethanol extract inconsistently over multiple liquid chromatography coupled with tandem mass spectrometry (LC/MS-MS) runs. A purified preparation of prodigiosin provided control of damping-off of cucumber caused by P. ultimum when applied as a seed treatment while ethanol extract of cell mass of strain Tn246, a transposon-mutant-derivative of strain N4-5, did not. Strain Tn246 contained a mini-Tn5 Km insertion in a prodigiosin biosynthetic gene and was deficient in production of prodigiosin. All other compounds detected in N4-5 extract were detected in the Tn246 extract. This is the first report demonstrating that prodigiosin can control a plant disease. Other compounds in ethanol extract of strain N4-5 may contribute to disease control.
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Affiliation(s)
- Daniel P Roberts
- Sustainable Agricultural Systems Laboratory, USDA-Agricultural Research Service, Beltsville Agricultural Research Center, BLDG 001, Rm. 245B, Beltsville, MD, 20705, USA.
| | - Kaitlyn Selmer
- Sustainable Agricultural Systems Laboratory, USDA-Agricultural Research Service, Beltsville Agricultural Research Center, BLDG 001, Rm. 245B, Beltsville, MD, 20705, USA
- Agios Pharmaceuticals, 88 Sidney St, Cambridge, MA, USA
| | - Robert Lupitskyy
- Sustainable Agricultural Systems Laboratory, USDA-Agricultural Research Service, Beltsville Agricultural Research Center, BLDG 001, Rm. 245B, Beltsville, MD, 20705, USA
- TIC Gums, 10552 Philadelphia Rd., White Marsh, MD, 21162, USA
| | - Clifford Rice
- Sustainable Agricultural Systems Laboratory, USDA-Agricultural Research Service, Beltsville Agricultural Research Center, BLDG 001, Rm. 245B, Beltsville, MD, 20705, USA
| | - Jeffrey S Buyer
- Sustainable Agricultural Systems Laboratory, USDA-Agricultural Research Service, Beltsville Agricultural Research Center, BLDG 001, Rm. 245B, Beltsville, MD, 20705, USA
| | - Jude E Maul
- Sustainable Agricultural Systems Laboratory, USDA-Agricultural Research Service, Beltsville Agricultural Research Center, BLDG 001, Rm. 245B, Beltsville, MD, 20705, USA
| | - Dilip K Lakshman
- Sustainable Agricultural Systems Laboratory, USDA-Agricultural Research Service, Beltsville Agricultural Research Center, BLDG 001, Rm. 245B, Beltsville, MD, 20705, USA
| | - Jorge DeSouza
- Departamento de Fitopatologia, Universidade Federal de Lavras, Lavras, 37200, Brazil
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Roberts DP, McKenna LF, Hu X, Lohrke SM, Kong HS, de Souza JT, Baker CJ, Lydon J. Mutation in cyaA in Enterobacter cloacae decreases cucumber root colonization. Arch Microbiol 2006; 187:101-15. [PMID: 17024489 DOI: 10.1007/s00203-006-0177-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Revised: 08/29/2006] [Accepted: 09/01/2006] [Indexed: 10/24/2022]
Abstract
Strains of Enterobacter cloacae show promise as biological control agents for Pythium ultimum-induced damping-off on cucumber and other crops. Enterobacter cloacae M59 is a mini-Tn5 Km transposon mutant of strain 501R3. Populations of M59 were significantly lower on cucumber roots and decreased much more rapidly than those of strain 501R3 with increasing distance from the soil line. Strain M59 was decreased or deficient in growth and chemotaxis on most individual compounds detected in cucumber root exudate and on a synthetic cucumber root exudate medium. Strain M59 was also slightly less acid resistant than strain 501R3. Molecular characterization of strain M59 demonstrated that mini-Tn5 Km was inserted in cyaA, which encodes adenylate cyclase. Adenylate cyclase catalyzes the formation of cAMP and cAMP levels in cell lysates from strain M59 were approximately 2% those of strain 501R3. Addition of exogenous, nonphysiological concentrations of cAMP to strain M59 restored growth (1 mM) and chemotaxis (5 mM) on synthetic cucumber root exudate and increased cucumber seedling colonization (5 mM) by this strain without serving as a source of reduced carbon, nitrogen, or phosphorous. These results demonstrate a role for cyaA in colonization of cucumber roots by Enterobacter cloacae.
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Affiliation(s)
- Daniel P Roberts
- Sustainable Agricultural Systems Laboratory, USDA-Agricultural Research Service, Bldg. 001, Rm. 140, 10300 Baltimore Avenue, Beltsville, MD 20705-2350, USA.
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Lohrke SM, Dery PD, Li W, Reedy R, Kobayashi DY, Roberts DR. Mutation of rpiA in Enterobacter cloacae decreases seed and root colonization and biocontrol of damping-off caused by Pythium ultimum on cucumber. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2002; 15:817-825. [PMID: 12182339 DOI: 10.1094/mpmi.2002.15.8.817] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Strains of Enterobacter cloacae show promise as biocontrol agents for Pythium ultimum-induced damping-off on cucumber and other crops. E. cloacae A145 is a mini-Tn5 Km transposon mutant of strain 501R3 that was significantly reduced in suppression of damping-off on cucumber caused by P. ultimum. Strain A145 was deficient in colonization of cucumber, sunflower, and wheat seeds and significantly reduced in colonization of corn and cowpea seeds relative to strain 501R3. Populations of strain A145 were also significantly lower than those of strain 501R3 at all sampling times in cucumber, wheat, and sunflower rhizosphere. Populations of strain A145 were not detectable in any rhizosphere after 42 days, while populations of strain 501R3 remained at substantial levels throughout all experiments. Molecular characterization of strain A145 indicated mini-Tn5 Km was inserted in a region of the E. cloacae genome with a high degree of DNA and amino acid sequence similarity to rpiA, which encodes ribose-5-phosphate isomerase. In Escherichia coli, RpiA catalyzes the interconversion of ribose-5-phosphate and ribulose-5-phosphate and is a key enzyme in the pentose phosphate pathway. Ribose-5-phosphate isomerase activity in cell lysates from strain A145 was approximately 3.5% of that from strain 501R3. In addition, strain A145 was a ribose auxotroph, as expected for an rpiA mutant. Introduction of a 1.0-kb DNA fragment containing only the rpiA homologue into strain A145 restored ribose phosphate isomerase activity, prototrophy, seedling colonization, and disease suppression to levels similar to those associated with strain 501R3. Experiments reported here indicate a key role for rpiA and possibly the pentose phosphate pathway in suppression of damping-off and colonization of subterranean portions of plants by E. cloacae.
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Affiliation(s)
- Scott M Lohrke
- Sustainable Agricultural Systems Laboratory, USDA-ARS, Beltsville, MD 20705, USA
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Roberts DP, Dery PD, Yucel I, Buyer JS. Importance of pfkA for rapid growth of Enterobacter cloacae during colonization of crop seeds. Appl Environ Microbiol 2000; 66:87-91. [PMID: 10618207 PMCID: PMC91789 DOI: 10.1128/aem.66.1.87-91.2000] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/1999] [Accepted: 10/19/1999] [Indexed: 11/20/2022] Open
Abstract
Enterobacter cloacae A-11 is a prototrophic, glycolytic mutant of strain 501R3 with a single transposon insertion in pfkA. The populations of strain A-11 on cucumber and radish seeds were smaller than the populations of strain 501R3 in natural soil, but the populations of these two strains on pea, soybean, sunflower, and sweet corn seeds were similar (D. P. Roberts, P. D. Dery, I. Yucel, J. Buyer, M. A. Holtman, and D. Y. Kobayashi, Appl. Environ. Microbiol. 65:2513-2519, 1999). The net effect of the mutation in pfkA in vitro was a shift from rapid growth on certain carbohydrates detected in seed exudates to much slower growth on other carbohydrates, amino acids, and organic acids. The impact of the mutation in pfkA was greatest on the growth rate of E. cloacae on the seeds that released the smallest quantities of fructose, other carbohydrates, and amino acids. Corn, pea, soybean, and sunflower seeds released total amounts of carbohydrates and amino acids at rates that were approximately 10- to 100-fold greater than the rates observed with cucumber and radish seeds for the first 24 h after inhibition began. The growth rate of strain A-11 was significantly less (50% less) than the growth rate of strain 501R3 on radish seeds, and the growth rate of strain A-11 was too low to estimate on cucumber seeds in sterile sand for the first 24 h after inhibition began. The growth rate of strain A-11 was also significantly lower on soybean seeds, but it was only 17% lower than the growth rate of strain 501R3. The growth rates of strains 501R3 and A-11 were similar on pea, sunflower, and corn seeds in sterile sand for the first 30 h after imbibition began. Large reductions in the growth rates of strain A-11 on seeds were correlated with subsequent decreased levels of colonization of seeds compared to the levels of colonization of strain 501R3. The strain A-11 populations were significantly smaller than the strain 501R3 populations only on radish and cucumber seeds. The mutation in pfkA appears to decrease the level of colonization by E. cloacae for seeds that release small quantities of reduced carbon compounds by decreasing the size of the pool of compounds that support rapid growth by this bacterium.
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Affiliation(s)
- D P Roberts
- Biocontrol of Plant Diseases Laboratory, USDA Agricultural Research Service, Beltsville, Maryland 20705, USA.
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Roberts DP, Dery PD, Yucel I, Buyer J, Holtman MA, Kobayashi DY. Role of pfkA and general carbohydrate catabolism in seed colonization by Enterobacter cloacae. Appl Environ Microbiol 1999; 65:2513-9. [PMID: 10347036 PMCID: PMC91371 DOI: 10.1128/aem.65.6.2513-2519.1999] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/1998] [Accepted: 03/19/1999] [Indexed: 11/20/2022] Open
Abstract
Enterobacter cloacae A-11 is a transposon mutant of strain 501R3 that was deficient in cucumber spermosphere colonization and in the utilization of certain carbohydrates (D. P. Roberts, C. J. Sheets, and J. S. Hartung, Can. J. Microbiol. 38:1128-1134, 1992). In vitro growth of strain A-11 was reduced or deficient on most carbohydrates that supported growth of strain 501R3 but was unaffected on fructose, glycerol, and all amino acids and organic acids tested. Colonization by strain A-11 was significantly reduced (P = 0.05) for cucumber and radish seeds compared to that of strain 501R3, but colonization of pea, soybean, sunflower, and sweet corn seeds was not reduced. Pea seeds released several orders of magnitude more total carbohydrates and amino acids than cucumber and radish seeds and approximately 4,000-fold more fructose. Fructose was the only carbohydrate detected in the seed exudates which supported wild-type levels of in vitro growth of strain A-11. Soybean, sunflower, and sweet corn seeds also released significantly greater amounts of fructose and total carbohydrates and amino acids than cucumber or radish seeds. The exogenous addition of fructose to cucumber and radish seeds at quantities similar to the total quantity of carbohydrates released from pea seeds over 96 h increased the populations of strain A-11 to levels comparable to those of strain 501R3 in sterile sand. Molecular characterization of strain A-11 indicated that the mini-Tn5 kanamycin transposon was inserted in a region of the genome with significant homology to pfkA, which encodes phosphofructo kinase. A comparison of strain A-11 with Escherichia coli DF456, a known pfkA mutant, indicated that the nutritional loss phenotypes were identical. Furthermore, the pfkA homolog cloned from E. cloacae 501R3 complemented the nutritional loss phenotypes of both E. coli DF456 and E. cloacae A-11 and restored colonization by strain A-11 to near wild-type levels. These genetic and biochemical restoration experiments provide strong evidence that the quantities of reduced carbon sources found in seed exudates and the ability of microbes to use these compounds play important roles in the colonization of the spermosphere.
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Affiliation(s)
- D P Roberts
- Biocontrol of Plant Diseases Laboratory, USDA Agricultural Research Service, Beltsville, Maryland 20705, USA.
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Postgate JR, Kent HM. Expression of Klebsiella pneumoniae nif genes in Proteus mirabilis. Arch Microbiol 1985; 142:289-94. [PMID: 3899045 DOI: 10.1007/bf00693406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Self-transmissible plasmids carrying his and nif genes from Klebsiella pneumoniae have been introduced into three his mutants of Proteus mirabilis: strains 5006-1, WR19 and WR20. Expression of his by the transconjugants was unequivocal, if slightly temperature-sensitive, but none was Nif+ when tested for acetylene reduction in anaerobic glucose medium using inocula from rich or glucose-minimal aerobic agar cultures. Succinate or pyruvate in place of glucose, low glucose, lower temperature or elevated Na2MoO4 did not allow nif expression and no nitrogenase MoFe-protein peptide was detected immunologically after exposure to conditions in which diazotrophic enterobacteria, normal or genetically constructed, derepress nif. One strain, P. mirabilis WR19, carrying the his nif Kmr plasmid pMF250 was examined in detail. The nif activator gene nifA was introduced on the plasmid pCK1. Such derivatives remained Nif- when tested, after aerobic growth on rich agar media, with normal or low glucose, with succinate or with elevated Mo. However, pre-conditioning by aerobic growth on glucose-minimal agar led to subsequent anaerobic expression of nif in glucose medium from pMF250 in WR19 carrying pCK1. NH+4 or proline could serve as N-source in the glucose-minimal agar. Maximum activity was about 5% of that of K. pneumoniae in our assay conditions. Material cross-reacting with anti-serum to the nitrogenase MoFe protein was formed. Nitrogenase activity was not 'switched off' by NH+4. P. mirabilis WR19 (pCK1) showed NH+4-constitutive temperature-sensitive kanamycin resistance (a nif-related phenotype of this plasmid) in aerobic glucose minimal medium.(ABSTRACT TRUNCATED AT 250 WORDS)
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