Association of Tobacco Leafspot Bacteria with Roots of Crop Plants

Valleau, W. D.; Johnson, E. M.; Diachun, S.

doi:10.1126/science.96.2485.164

Cited by 10 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…23 Diachun and coworkers' work in the 1940s provided evidence of this site and put forth a model of deleterious consequences for the infested plants. 24 " 25 Since that time, other workers have noted seemingly unexplained poor growth and minimal seedling survival in areas where host plants of this organism have been grown. Careful studies showed that the bacterium does not invade the root, but rather lives on the root surface.…”

Section: Isotope and Nuclear Chemistry Division Annualmentioning

confidence: 99%

“…using an in-core irradiation facility, conducted a series of measurements of radiation damage to metals proposed for use in controlled fusion reactors. The longest, irradiation was 5 weeks; the total length of all irradiations was 545 h. • Using a new high-resolution (5.2-keV FWHM at 11 MeV) intrinsic germanium detector, we have studied the thermal neutron-capture gamma-ray spectra emitted from the following target isotopes: 24 Mg. 25 Mg. 26 Mg. "Ca (1.3 x 10 7 yr). 93 Zr (1.5 x 10 6 yr).…”

Section: Irradiation Facilitiesmentioning

confidence: 99%

See 1 more Smart Citation

Isotope and Nuclear Chemistry Division annual report FY 1989, October 1988--September 1989

Heiken¹,

Minahan²

1990

View full text Add to dashboard Cite

The Medical (Udioisotopes Research Program is investigating methods that will allow us to label molecules, which can then be used to image, diagnose, and treat various diseases. The two major components of this project are to develop labeling chemistry and to study targeting techniques. Articles relate*! to this research can be round in Sees. 4 and I Oof this report Right: We use cell-culture techniques to evaluate the ability oflymph nodes (red medium) and tumor cells (orange medium) to concentrate various radiopharmaceuticals.Below: The gamma-camera terminal displays the uptake of a radiophamaceutical in tissue. In this example, color gradation corresponds to the concentration of radiopharmaceutical (white > red > yellow > blue) in the heart.Above: We usa computer modeling to design specific chelating agents (metal-binding molecules); these structures are easily examined on the terminal. In this model, nitrogen atoms (blue) are the binding sites and are held in rigid conformation by carbon atoms (green); hydrogen atoms are shown in white. --/ , --J-)tope to specific tumor sites. .""." chromotograplw is used to separate the orange metalated porphyrin that contains Lu from the green unmetalated form.Front Cover: This photo is a gamma-camera image; the subject, an anesthetized rat, had been injected with a compound to which a radioisotope had been attached, or "labeled." In the initial steps of this experiment, the front paws of the rat had been injected with a chemical that caused an inflammation. The 67 Cu-labeled porphyrin ""•; theqjnjected. The majority of the labeled porphyrin is localized le jjfontJjws^pm^^tSjty is also evident in the liver. (Blue cafes tirearejSjjJf TOftflit concentration of radiopharmaceutical, ana yefaft wdicBwrrwcftsrate concentration, and green areas have the least concentration.

show abstract

Section: Isotope and Nuclear Chemistry Division Annualmentioning

confidence: 99%

Section: Irradiation Facilitiesmentioning

confidence: 99%

Isotope and Nuclear Chemistry Division annual report FY 1989, October 1988--September 1989

Heiken¹,

Minahan²

1990

View full text Add to dashboard Cite

show abstract

“…using an in-core irradiation facility, conducted a series of measurements of radiation damage to metals proposed for use in controlled fusion reactors. The longest, irradiation was 5 weeks; the total length of all irradiations was 545 h. • Using a new high-resolution intrinsic germanium detector, we have studied the thermal neutron-capture gamma-ray spectra emitted from the following target isotopes: 24 Mg. 25 Mg. 26 Mg. "Ca (1.3 x 10 7 yr). 93 Zr (1.5 x 10 6 yr).…”

Section: Ifj2mentioning

confidence: 99%

Isotope and Nuclear Chemistry Division annual report FY 1986, October 1985-September 1986

Heiken¹

1987

View full text Add to dashboard Cite

The Medical (Udioisotopes Research Program is investigating methods that will allow us to label molecules, which can then be used to image, diagnose, and treat various diseases. The two major components of this project are to develop labeling chemistry and to study targeting techniques. Articles relate*! to this research can be round in Sees. 4 and I Oof this report Right: We use cell-culture techniques to evaluate the ability oflymph nodes (red medium) and tumor cells (orange medium) to concentrate various radiopharmaceuticals. Below: The gamma-camera terminal displays the uptake of a radiophamaceutical in tissue. In this example, color gradation corresponds to the concentration of radiopharmaceutical (white > red > yellow > blue) in the heart. Above: We usa computer modeling to design specific chelating agents (metal-binding molecules); these structures are easily examined on the terminal. In this model, nitrogen atoms (blue) are the binding sites and are held in rigid conformation by carbon atoms (green); hydrogen atoms are shown in white. 1-/ ,-J-)tope to specific tumor sites. .""." chromotograplw is used to separate the orange metalated porphyrin that contains Lu from the green unmetalated form. Front Cover: This photo is a gamma-camera image; the subject, an anesthetized rat, had been injected with a compound to which a radioisotope had been attached, or "labeled." In the initial steps of this experiment, the front paws of the rat had been injected with a chemical that caused an inflammation. The 67 Cu-labeled porphyrin ""•; theqjnjected. The majority of the labeled porphyrin is localized le jjfontJjws^pm^^tSjty is also evident in the liver. (Blue cafes tirearejSjjJf TOftflit concentration of radiopharmaceutical, ana yefaft wdicBwrrwcftsrate concentration, and green areas have the least concentration.

show abstract

“…P. syringae pv tabaci is regarded as a leaf pathogen and is recognized as the causal agent of wildfire disease in tobacco. However, pv tabaci has been found associated with the roots of various crop, pasture, and weed plants in addition to those of its natural host, tobacco (19,20). Although a role for this pathogen in the causation of a leaf spot disease (8) and the presence of this pathovar in the rhizosphere (19,20) have been known for some time, it is not understood how plant growth and development may be affected by the presence of this pathogen in the rhizosphere or by the production of T-(l-L in the rhizosphere of infested plants.…”

Section: -[3-hydroxy-2-oxo-azacyclobutan-3-yl]-butanoic Acid) (T-b-l)2mentioning

confidence: 99%

Effects of Tabtoxinine-β-Lactam on Nitrogen Metabolism in Avena sativa L. Roots

Knight

Durbin²,

Langston-Unkefer³

1986

Plant Physiol.

View full text Add to dashboard Cite

The effects of tabtoxinine-,8-lactam (T-,i-L) on nitrate uptake and glutamine synthetase (GS) and nitrate reductase (NR) activities in roots of Avena sativa seedlings were determined. Seven-day-old oat seedlings placed in a 10 mm KNO3 and 0.5 mm T-,B-L solution for 24 hours took up T-f,-L and lost approximately 90% of their root GS activity. 1H1T-,B-L taken up by roots of seven-day-old oat seedlings was associated with GS immunoprecipitated from the extract of these roots. Total nitrate uptake and in vivo NR activity were decreased approximately 50% in the T-,B-L treated roots. However, T-,6-L uptake did not affect the induction phases of nitrate uptake or reduction, nor did it inhibit in vitro NR activity. Thus, the decrease in nitrate uptake and reduction is a secondary effect of T-Ot-L action. Roots of seven-day-old oat seedlings were inoculated with Pseudomonas syringae pv tabaci (Tox+) and the pathogen population in the rhizosphere was estimated by dilution plate count; 6 x 10" bacteria were recovered after 3 days, as compared to the original inoculation with 7 x 10' bacteria, indicating a significant growth of the pathogen in the rhizosphere. The bacteria recovered from the rhizosphere caused chlorosis in tobacco leaves and produced T-,j-L in culture; I x 10i4 bacteria were recovered from roots of seedlings inoculated with P. syringae pv tabaci (Tox-) using the same inoculation and assay procedure as for the pv tabaci(Tox+). Extracts of surface-sterilized roots previously inoculated with P. syringae pv tabaci (Tox+) did not produce viable bacterial cultures when plated out on a complete medium. Oat seedlings growing in sand culture and inoculated with P. syringae pv tabaci (Tox+) had developed chlorosis, and root GS activity had declined to less than 10% of controls after 3 days. Conversely, seedlings inoculated with P. syringae pv tabaci (Tox-) never developed chlorosis and maintained normal levels of GS activity. All oat plants inoculated with P. syringae pv tabaci (Tox+) died within 7 days after inoculation as compared to the plants inoculated with P. syringae pv tabaci (Tox-) which grew to maturity.The phytopathogenic bacterium Pseudomonas syringae pv tabaci and several closely related pathovars produce tabtoxin which when hydrolyzed to tabtoxinine-#-lactam (18) (2-amino-4-[3-hydroxy-2-oxo-azacyclobutan-3-yl]-butanoic acid) (T-,B-L)2 is an irreversible inhibitor of GS (EC 6.3.2.1.) in vivo (7, 16). T-,B-L is not a host-selective toxin and inactivates GS purified from a variety of sources (4, 7).

show abstract

Association of Tobacco Leafspot Bacteria with Roots of Crop Plants

Cited by 10 publications

References 0 publications

Isotope and Nuclear Chemistry Division annual report FY 1989, October 1988--September 1989

Isotope and Nuclear Chemistry Division annual report FY 1989, October 1988--September 1989

Isotope and Nuclear Chemistry Division annual report FY 1986, October 1985-September 1986

Effects of Tabtoxinine-β-Lactam on Nitrogen Metabolism in Avena sativa L. Roots

Contact Info

Product

Resources

About