Tesfaye Mengiste

Associate Professsor

Department: Botany and Plant Pathology
Phone: 765.494.0599
Fax: 765.494.0363
Office: Lilly Hall, Room G-316
E-mail: mengiste@purdue.edu

Area of Expertise: Molecular Genetics of Plant Immunity - with emphasis on host defense response to necrotrophic fungi.

Plants are exposed to stresses from a battery of biotic and abiotic agents resulting in crop losses. Fungi, bacteria, nematodes, insects, and viruses have all evolved strategies to exploit their hosts. The evolutionary tug of war between pathogens and their host has led to the development of polymorphic defense strategies required for resistance. Important among these is the plant ‘innate immune system’ with a complex set of genes involved in recognition, signal transduction, and activation of defense responses. Plants also possess pathogen non-specific broad-spectrum resistance. Both of those disease resistance responses have received considerable attention and consequently important components have been isolated or genetically defined.

However, plant genetic and cellular mechanisms involved in host response to necrotrophic pathogens such as Botrytis cinerea are poorly understood. Our research aims at the elucidation of the genetic and molecular control of plant defense responses to necrotrophic pathogens, their interaction with other defense and stress response pathways. Our current research involves the genetic identification of plant loci required for Botrytis resistance through analysis of mutations that enhance resistance or susceptibility. We clone genes defined by such mutations and determine their specific mechanism of function in disease resistance to pathogens in general and Botrytis in particular. Genetic and molecular studies will help place these genes in signal transduction pathways.

Why Botrytis?
My research interest with Botrytis is because of its significance as a crop pathogen. It causes the gray mold disease in a wide range of crop plants. Host responses to necrotrophs appear to be controlled by a different set of genes and signaling molecules than those mediating response to biotrophic pathogens. Genetic variation for resistance to Botrytis has been documented in plants. However, no genetic resistance has been identified in any plant species so far. So what defense responses are triggered by Botrytis? What are the specific patterns associated with Botrytis infection? What are the genetic regulators of Botrytis response? What are the signaling molecules that mediate such response? We use genetic, molecular and genomic approaches to find answers to those interesting biological questions. Such findings will help design effective and sustainable crop protection strategies through the breeding of resistant cultivars. Our research will also contribute to the body of knowledge on host defense response to fungal pathogens particularly to necrotrophs.

Botrytis also causes the noble rot. The fungus develops on grapes under certain environmental conditions and causes the grape to shrivel, concentrating and intensifying both sugar and flavor. Botrytised grapes make very elegant, intensely flavored dessert wines.

- Recent Publications

Mengiste, T., H. G. Mang, K. A. Laluk, D. K. Kosma, B. R. Cooper, H. C. Park, S. AbuQamar, C. Boccongelli, S. Miyazaki, G. Chilosi, H. L. Bohnert, R. A. Bressan, & M. A. Jenks (2009). The Arabidopsis RESURRECTION1 (RST1) gene regulates leaf cuticle lipids and suppresses jasmonate-dependent plant defense. Plant Physiology, 151, 290-305.

Dhawan, R., H. Luo, A. Forester, S. AbuQamar, H. Du, S. Briggs, O. MittlestenScheid, & T. Mengiste (2009). HISTONE MONOUBIQUITINATION 1 interacts with the MED21 subunit of. The Plant Cell, 21, 1000-1019.

Wang, X., B. M. Vindhya, S. Basnayake, H. Zhang, G. Li, W. Li, N. Virk, T. Mengiste, & F. Song (2009). The Arabidopsis ATAF1, a NAC transcription factor, 1 is a negative regulator of defense responses against biotrophic and necrotrophic pathogens. Molecular Plant Microbe Interactions, 22, 1227-1238.

AbuQamar, S., M. Chai, H. Luo, F. Song, & T. Mengiste (2008). AbuQamar S, Chai, M, Luo, H, Song, F, and Mengiste, T. (2008). Tomato Protein Kinase 1b mediates signaling of plant responses to necrotrophic fungi and insect herbivory. Plant Cell, 20, 1964-1983.

AbuQamar, S., H. Luo, K. Laluk, M. M. Mickelbart, & T. Mengiste (2008). Cross-talk between biotic and abiotic stress responses in tomato is mediated by the AIM1 transcription factor. The Plant Journal, 58, 347-360.

Kemmerling, B., B. Schwedt, P. Rodriguez, S. Mazzotta, M. Frank, S. F. A. Qamar, T. Mengiste, S. Betsuyaku, J. Parker, C. Mussig, B. P. Thomma, C. Albrecht, S. C. de Vries, H. Hirt, & T. Nurnberger (2007). The BRI1-Associated Kinase 1, BAK1, has a brassinolide-independent role in plant cell-death control. Currrent Biology, 17, 1116-1122.

Lee, J., J. Nam, H. C. Park, G. Na, K. Miura, J. B. Jin, C. Y. Yoo, D. Baek, D. H. Kim, J. C. Jeong, D. Kim, S. Y. Lee, D. Salt, T. Mengiste, Q. Gong, S. Ma, H. Bohnert, S. Kwak, R. Bressan, P. Hasegawa, & D. J. Yun (2007). Salicylic acid-mediated innate immunity in Arabidopsis is regulated by SIZ1 SUMO E3 ligase. Plant Journal, 49, 79-90.

Kang, C. H., W. Y. Jung, Y. H. Kang, J. Y. Kim, D. G. Kim, J. C. Jeong, D. W. Baek, J. B. Jin, W. S. Chung, T. Mengiste, H. Koiwa, S. S. Kwak, J. D. Bahk, S. Y. Lee, J. S. Nam, & M. J. Cho (2006). AtBAG6, a novel calmodulin binding protein, induces programmed cell death in yeast and plants. Cell Death and Differentiation, 13, 84-95.

Zheng, Z., S. F. A. Qamar, Z. Chen, & T. Mengiste (2006). Arabidopsis WRKY33 Transcription Factor Is Required for Resistance to Necrotrophic Fungal Pathogens. The Plant Journal, 48, 592-605.

Mengiste, T. (2006). Expression profiling and mutant analysis reveals complex regulatory networks involved in Arabidopsis response to Botrytis infection. Plant Journal, 48, 28-44.