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Tesfaye Mengiste

Botany and Plant Pathology 

  • Professor
765.494.0599
765.494.0363
Lilly Hall Room G-452

     
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.

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.

Selected Publications

Lai, Z., & Mengiste, T. (2013). Genetic and cellular mechanisms regulating plant responses to necrotrophic pathogens. Current Opinion in Plant Pathology, 16(4), 505-512.

Lin, W., Lu, D., Gao, X., Jiang, S., Ma, X., Wang, Z., . . . Shan, L. (2013). Inverse modulation of plant immune and brassinosteroid signaling pathways by the receptor-like cytoplasmic kinase BIK1. PNAS, 110(29), 12114-12119.

Prusky, D., Alkan, N., Mengiste, T., & Fluhr, R. (2013). Quiescent and necrotrophic lifestyle choice during postharvest disease development. Annual Reviews of Phytopathology, 51, 155-176. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/23682917

Mengiste, T. (2012). Plant immunity to Necrotrophs. Annual Reviews of Phytopathology, 50, 267-294.

Nambeesan, S., AbuQamar, S., Laluk, K., Mickelbart, M. V., Mengiste, T., & Handa, A. (2012). Polyamines attenuate ethylene-mediated defense responses to abrogate resistance to Botrytis cinerea in tomato. Plant Physiology, 158(2), 1034-1045.

Laluk, K., Luo, H., Chai, M., Dhawan, R., Lai, Z., & Mengiste, T. (2011). Biochemical and Genetic Requirements for Function of the Immune Response Regulator Botrytis Induced Kinase1 in Plant Growth, Ethylene Signaling, and PAMP Triggered Immunity in Arabidopsis. Plant Cell, 23(8), 2831-2849. Retrieved from http://www.plantcell.org/content/23/8/2831.full?sid=0e6e9973-7202-45ba-ae4f-bd54f08eb3ed

Laluk, K., & Mengiste, T. (2011). The Arabidopsis extracellular UNUSUAL SERINE PROTEASE INHIBITOR functions in resistance to necrotophic fungi and insect herbivory. Plant Journal, 68(3), 480-494. Retrieved from http://onlinelibrary.wiley.com/doi/10.1111/j.1365-313X.2011.04702.x/full

Laluk, K., Abuqamar, S., & Mengiste, T. (2011). The Arabidopsis Mitochondria-Localized Pentatricopeptide Repeat Protein PGN Functions in Defense against Necrotrophic Fungi and Abiotic Stress Tolerance. Plant Physiology, 156, 2053-2068.

Luo, H., Laluk, K., Veronese, P., Song, F., & Mengiste, T. (2010). The Arabidopsis Botrytis Susceptible1 Interactor defines a subclass of RING E3 ligases that regulate pathogen and stress response. Plant Physiology, 154, 1766-1782.

Zhang, J., Li, W., Xiang, T., Liu, Z., Laluk, K., Ding, X., . . . Zhou, J. M. (2010). Receptor-like cytoplasmic kinases integrate signaling from multiple plant immune receptors and are targeted by a Pseudomonas syringae effector. Cell Host and Microbe, 7, 259-261.