Faculty

Timothy McNellis

Associate Professor of Plant Pathology & Environmental Microbiology

318 Buckhout Lab
University Park, PA

Email twm4@psu.edu
Phone 814-863-7646

Overview

Genetics, molecular biology and physiology of plant interactions with phytopathogenic bacteria. Signal transduction events involved in plant disease resistance. Genetic control of plant hypersensitive cell death.

Areas of Expertise

Erwinia Amylovora Keyphrases
Erwinia Amylovora Immunology and Microbiology
Apple Keyphrases
Arabidopsis Biochemistry, Genetics and Molecular Biology
Arabidopsis Keyphrases
Virulence Keyphrases
Wild Type Immunology and Microbiology
Wild Type Biochemistry, Genetics and Molecular Biology

Erwinia amylovora amino acid auxotrophy and epiphytic growth on apple stigmas
Neil P. Schultes, Judith P. Sinn, Eric S. Swenson, Louis Orifice, Cameron Ryan, Timothy W. McNellis, Jul 2026, In: Physiological and Molecular Plant Pathology
Date: Jul 2026

The Harpin-Induced Hypersensitive Reaction in Nicotiana tabacum Requires Wall-Associated Kinase 2
Jeremy B. Held, Judith P. Sinn, Brian H. Kvitko, Timothy W. McNellis, May 2025, In: Molecular plant pathology
Date: May 2025

Putative Transcriptional Regulator LysR1 Is Required for Full Virulence of Erwinia amylovora
Sara M. Klee, Judith P. Sinn, Jeremy B. Held, Francesco Pacini, Aleah C. Holmes, Melissa Finley, Brian L. Lehman, Kari A. Peter, Timothy W. McNellis, 2025, In: Plant Pathology
Date: 2025

Synthesis of aspartic acid and tyrosine by the fire blight pathogen Erwinia amylovora is not required for proliferation on apple flower stigmas or virulence in fruitlets
Neil P. Schultes, Judith Pawloski Sinn, Eric S. Swenson, Timothy W. McNellis, Aug 2024, In: Journal of Applied Microbiology
Date: Aug 2024

Arabidopsis Wall-Associated Kinase 3 is required for harpin-activated immune responses
Jeremy B. Held, Taran Rowles, William Schulz, Timothy W. McNellis, 2024, In: New Phytologist
Date: 2024

Glyceraldehyde-3-phosphate dehydrogenase is required for fire blight disease establishment in apple fruitlets
Neil P. Schultes, Judith P. Sinn, Timothy W. McNellis, Jul 2023, In: Physiological and Molecular Plant Pathology
Date: Jul 2023

Putative transcription antiterminator RfaH contributes to Erwinia amylovora virulence
Sara M. Klee, Judith P. Sinn, Jeremy Held, Chad Vosburg, Aleah C. Holmes, Brian L. Lehman, Kari A. Peter, Timothy W. McNellis, 2022, In: Molecular plant pathology
Date: 2022

Virulence genetics of an erwinia amylovora putative polysaccharide transporter family member
Sara M. Klee, Judith P. Sinn, Elena Christian, Aleah C. Holmes, Kaixi Zhao, Brian L. Lehman, Kari A. Peter, Cristina Rosa, Timothy W. McNellis, Nov 2020, In: Journal of bacteriology
Date: Nov 2020

Flowering Locus T chimeric protein induces floral precocity in edible citrus
Judith P. Sinn, Jeremy B. Held, Chad Vosburg, Sara M. Klee, Vladimir Orbovic, Earl L. Taylor, Tim R. Gottwald, Ed Stover, Gloria A. Moore, Timothy W. McNellis, 2020, In: Plant Biotechnology Journal
Date: 2020

Erwinia amylovora auxotrophic mutant exometabolomics and virulence on apples
Sara M. Klee, Judith P. Sinn, Melissa Finley, Erik L. Allman, Philip B. Smith, Osaretin Aimufua, Viji Sitther, Brian L. Lehman, Teresa Krawczyk, Kari A. Peter, Timothy W. McNellis, 2019, In: Applied and environmental microbiology
Date: 2019

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Genetic and molecular analysis of an allelic series of cop1 mutants suggests functional roles for the multiple protein domains
Timothy W. McNells, Albrecht G. Von Arnim, Takashi Araki, Yoshibumi Komeda, Simon Miséra, Xing Wang Deng, Apr 1994, In: Plant Cell
Citations: 397

Light control of seedling morphogenetic pattern
Timothy W. McNellis, Xing Wang Deng, Nov 1995, In: Plant Cell
Citations: 232

Arabidopsis COP8, COP10, and COP11 genes are involved in repression of photomorphogenic development in darkness
Ning Wei, Shing F. Kwok, Albrecht G. Von Arnim, Angela Lee, Timothy W. McNellis, Barry Piekos, Xing Wang Deng, May 1994, In: Plant Cell
Citations: 177

A humidity-sensitive Arabidopsis copine mutant exhibits precocious cell death and increased disease resistance
N. Jambunathan, J. M. Siani, T. W. McNellis, 2001, In: Plant Cell
Citations: 174

Overexpression of arabidopsis COP1 results in partial suppression of light-mediated development
Timothy W. McNellis, Albrecht G. Von Arnim, Xing Wang Deng, Oct 1994, In: Plant Cell
Citations: 147

Glucocorticoid-inducible expression of a bacterial avirulence gene in transgenic ARABIDOPSIS INDUCES Hypersensitive cell death
Timothy W. McNellis, Mary Beth Mudgett, Karen Li, Takashi Aoyama, Diana Horvath, Nam Hai Chua, Brian J. Staskawicz, 1998, In: Plant Journal
Citations: 137

Fibrillin protein function
Dharmendra K. Singh, Timothy W. McNellis, Aug 1 2011, In: Trends in Plant Science
Citations: 122

Functional dissection of Arabidopsis COP1 reveals specific roles of its three structural modules in light control of seedling development
Keiko U. Torii, Timothy W. McNellis, Xing Wang Deng, Oct 1 1998, In: EMBO Journal
Citations: 117

Rootstock effects on gene expression patterns in apple tree scions
Philip J. Jensen, Jo Rytter, Elizabeth A. Detwiler, James W. Travis, Timothy W. McNellis, Nov 2003, In: Plant molecular biology
Citations: 110

FIBRILLIN4 is required for plastoglobule development and stress resistance in apple and arabidopsis
Dharmendra K. Singh, Siela N. Maximova, Philip J. Jensen, Brian L. Lehman, Henry K. Ngugi, Timothy W. McNellis, Nov 2010, In: Plant physiology
Citations: 87

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Centers & Institutes

Plant Biology IGDP

Matt Langland, who recently graduated from Penn State with a bachelor’s degree in environmental resource management, examines salt-encrusted soils in New Mexico's migratory bird habitats. Credit: Contributed photo. All Rights Reserved.

July 16, 2025

College of Ag Sciences grant program supports student learning, experiences

June 03, 2020

Timothy McNellis

Overview

Areas of Expertise

College of Ag Sciences grant program supports student learning, experiences

Huck graduate students among NSF award recipients

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