Professor and Plant Pathologist
Research Specialty and Interests
Hadwiger’s lab has cloned numerous defense genes. They are currently studying the regulation of these genes (gene promoters). The main objective is to devise ways to control disease by understanding and manipulating the plant’s own defense responses. The lab has successfully developed treatments to induce immunity in plants. They have also engineered plants to suppress invasion by plant pathogens. They have discovered transcription factors whose synthesis is inversely related to the disease resistance response. They have discovered two components that are released from a wide variety of fungal pathogens, chitosan, a derivative of the chitin found in the fungal wall and DNases coded by the fungal genome. Both are capable of inducing the total immunity in pea tissue to pea pathogens. Mechanisms for manipulating resistance in many plant species include transferring the gene for chitin deacetylase to the plant enabling the plant to immediately convert the walls of challenging fungal pathogens to chitosan and thus continually induce the defense response. Alternately the DNase genes can (and have been transferred to potato and tobacco plants) be added to the plant genome to again continually activate the defense response. At the molecular level they have discovered that defense response genes are activated three ways: By conformational changes or cleavages in the plant DNA, by removal of histone H2A from the gene’s promoter site, and by very low levels of phosphatase inhibitors
- Researched in Freiburg Germany with Klaus Halbrock
- Researched in Davis, California (University of California) with Eric Conn
- J Isaac, SL Hartney, K Druffel, LA Hadwiger. 2009. The non-host disease resistance in peas: alterations in phosphorylation and ubiquitination of HMG A and histone H2A/H2B Plant Science 177:439-449
- LA Hadwiger, 2009. Localization predictions for gene products involved in non-host resistance responses in a model plant/fungal pathogen interaction. Plant Science 177:257-265.
- Hadwiger, L.E. 2008. Pea–Fusarium solani Interactions Contributions of a System Toward Understanding Disease Resistance. Phytopathology 98(4):372-379. PDF File
- Hartney, S., Carson, J. and L.A. Hadwiger. 2007. The use of chemical genomics to detect functional systems affecting the non-host disease resistance of pea toFusarium solani f. sp. phaseoli. Plant Science 172:45-56.
- Choi, J.J., Klosterman, S.J. and Hadwiger, L.A. 2001. A comparison of the effects of DNA damaging agents and biotic elicitors on the induction of plant defense genes, nuclear distortion and cell death. Plant Physiol. 125:752-762.
- Hadwiger, L. A., and McBride, P. O. 2006. Low level copper plus chitosan applications provide protection against late blight of potato. Online. Plant Health Progress doi:10.1094/PHP-2006-0406-01-RS.
- Choi, J.J., Klosterman, S.J. and Hadwiger, L. A. 2004. A promoter from pea gene DRR206 is suitable to regulate an elicitor-coding gene and develop disease resistance. Phytopathology 94:651-660.
- Klosterman, S.J., Choi, J.J., Chang, M.-M. And Hadwiger, L.A. 2001. Is chitosan’s defense response-inducing action mediated through the nuclear protein HMG-I (Y) in plants? In 3rd Int. Symposium on Chitin Enzymology. Ed: R.A.A. Muzzarelli, Atec Edizionic, Grottammare, Italy. (In press).
- Klosterman, S.J., Chen J., Choi, J.J., E.E. and L.A. Hadwiger. 2001. Characterization of a 20kDa DNase elicitor from Fusarium solani F. Sp. phaseoli and its expression at the onset of induced resistance in Pisum sativum. Mol. Plant Pathol.
- Klosterman, S.J., Choi, J.J., Hadwiger, L.A. 2001. Programmed cell death is not mediated by a p53 homolog in Pisum sativum Physiol. Mol. Plant Pathol. 56:197-206.
- Parsons, M.A. and Hadwiger, L.A. 1998. Photoactivated psoralens elicit defense genes and phytoalexin production in the pea plant. Photochem. Photobiol. 67:438-445.
- Culley, D.E., Horovitz, D., and Hadwiger, L.A. 1995. Molecular characterization of disease-resistance response gene DRR206-d from Pisum sativum. Plant Physiol. 107:301-302.
- Hadwiger, L.A., Chang, M.-M. and Parsons, M.A. 1995. Fusarium solani Dnase is a signal for increasing expression of nonhost disease resistance response genes, hypersensitivity and pisatin production. Mol. Plant-Microbe Interact. 8:871-879.
- Gerhold, D.L., Pettinger, A.J., and Hadwiger, L.A. 1993. Characterization of a plant-stimulated nuclease from Fusarium solani. Physiol. Mol. Plant pathol. 43:33-46.
- Chang, M.-M., Horovitz, D., Culley, D., Hadwiger, L.A. 1995. Molecular cloning and characterization of a pea chitinase gene expressed in response to wounding, fungal infection and the elicitor chitosan. Plant Mol. Biol. 28:105-111.
- Chang, M.-M., Hadwiger, L.A., Horovitz, D. 1992. Molecular characterization of a pea beta-1,3-glucanase induced by Fusarium solani and chitosan challenge. Plant Mol. Biol. 20:609-619.
Johnson Hall 359 (office) &
Hadwiger’s research results have been consistently presented at national meetings and in specialized symposia.