University of California

Wisconsin Alumni Research Foundation

Steven E Lindow

Cindy S Orser

Deane C Arny

Nickolas J Panopoulos

Brian J Staskawicz

Milton N Schroth

Karyn Newman

Gary L Anderson

Nickolas J Panapoulos

Joyce Loper

DSF-based microbial pathogens may be controlled by certain methods and compositions. A method of controlling diseases caused in a host organism by pathogenic microbial expression of &#x3b1;,&#x3b2; unsaturated fatty acid signal (DSF) molecules involves inoculating the host organism with a non-pathogenic microbe that disrupts &#x3b1;,&#x3b2; unsaturated fatty acid signal molecule-mediated cell-cell communication by the pathogenic microbe in the host organism. Microbes having protein expression that interferes with &#x3b1;,&#x3b2; unsaturated fatty acid signal molecule-mediated cell-cell communication by the pathogenic microbe in the host organism can be identified and isolated or engineered by transformation with DSF-interference (inhibition or activation) gene or genes. Genes conferring DSF-interference activity can also be expressed in organisms (e.g., plants) susceptible to diseases caused by microbes that use DSF, resulting in genetically resistant organisms.

Biological control of pathogenicity in microbes that use alpha, beta unsaturated fatty acid signal molecules

A method is provided of reducing fruit russetting by treating the surface of a fruit to reduce the amount of auxins present on the surface. In a preferred embodiment, the population of auxin-producing bacteria is reduced by providing a competing auxin-deficient bacterial population.

Microbial and chemical control of fruit russetting

Plant host acceptable microorganisms, which are ice nucleation deficient and use at least one nutrient from the plant also used by ice nucleating native microorganisms, are applied to a plant part at an early stage in the growth cycle. The multiplication of the native ice nucleating microorganisms is inhibited, so that under normal frost conditions encountered in the field, frost damage is substantially diminished. The non-nucleating microorganisms may be obtained by special selection procedures, selecting from naturally occuring microorganisms or mutagenized microorganisms, where additionally the organisms may be transformed to provide for other desirable properties.

Microorganism inhibition of frost damage to plants

Ice nucleation bacteria are modified in vitro to confer an ice nucleation deficient phenotype. Modification is accomplished by deletion, substitution, insertion, inversion, or transversion of a DNA segment within the gene locus responsible for the INA phenotype. By limiting such mutations to the particular gene locus, the modified microorganisms are genetically stable and free from random mutations which might adversely affect their competitive fitness. The modified microorganisms are useful for prevention of frost damage to susceptible plant hosts.

Ice nucleation deficient microorganisms by genetic manipulation

A novel pathovar has been isolated and purified, which pathovar most resembles Alternaria zinniae Pape, but has a host specificity for Italian thistle. By administering spores of this pathovar, called Alternaria sp., particularly shortly after emergence, Italian thistle growth is substantially inhibited. The spores of Alternaria sp. described in the subject invention have been deposited at the A.T.C.C. on Aug. 17, 1984 and given Accession No. 20723.

Mycological method for controlling italian thistle growth

DNA sequences encoding for plant growth promotant activity have been isolated and introduced into microorganisms. The modified organisms are able to confer plant growth promotant activity analogous to that of the DNA source host. Such modified hosts find use in promoting the growth of root crops by innoculating the rhizosphere with such microorganisms. E. coli HB101 (pS FL-1) was deposited at the A.T.C.C. on Oct. 8, 1982, and granted accession no. 39206.

Fluorescent siderophore genes

DNA sequences encoding for ice nucleation activity are isolated and introduced into unicellular hosts. The modified hosts demonstrate ice nucleation activity analogous to the DNA source host. The cellular products find use in inhibiting supercooling.

Ice nucleating microorganisms

Plant host acceptable microorganisms, which are ice nucleation deficient and use at least one nutrient from the plant also used by ice nucleating native microorganisms, are applied to a plant part at an early stage in the growth cycle. The multiplication of the native ice nucleating microorganisms is inhibited, so that under normal frost conditions encountered in the field, frost damage is substantially diminished. The non-nucleating microorganisms may be obtained by special selection procedures, selecting from naturally occurring microorganisms or mutagenized microorganisms, where additionally the organisms may be transformed to provide for other desirable properties. The following organisms have been deposited at the A.T.C.C. on Aug. 13, 1981; A5-01, A5-05-1, A5-06, A5-10-1, A5-26, and A4-2B-10.

Microrganism inhibition of frost damage to plants

The method for reducing the temperature at which freezing takes place in plants to reduce frost damage by the addition of non-ice nucleating bacteria to the plants prior to the onset of freezing temperature and preferably while the plants are in their seedling stage.

Method for reducing temperature at which plants freeze

The protection of plants against frost damage comprising treating the plants before the onset of freezing cold with bacterium M232A.

Growing community of inventors

Berkeley, CA, United States of America

Steven E Lindow