Universität zu Köln

Lawson, Aaron W. ORCID: 0000-0001-8164-2555 (2024). Cryo-EM resolution of immunoreceptor-pathogen effector interfaces for engineering enhanced disease resistance in crops. PhD thesis, Universität zu Köln.

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Abstract

Co-evolution between plants and pathogenic microbes leads to adaptive genetic changes that shape the development of the host immune system. A major component of plant innate immunity is the deployment of nucleotide-binding leucine rich repeat receptors (NLRs) with N-terminal coiled-coil domains (CNLs). Grass species including wheat and barley encode CNLs that detect pathogenic effector proteins, an interaction that results in a potent hypersensitive response (HR) that is associated with effector-triggered immunity (ETI). ETI can be evaded due to sequence alterations in virulent effectors to escape detection by their cognate CNLs. The molecular basis of receptor-effector interaction specificity is incompletely understood. In this thesis, I present the cryogenic electron microscopy (cryo-EM) structure of the wheat Sr35 CNL in complex with its matching effector AvrSr35 from Puccinia graminis f sp tritici (Pgt) as the first structure of an activated NLR heterocomplex from a crop species. In addition, I report the cryo-EM structure of the barley CNL MLA13 in complex with its cognate effector AVRA13-1 from Blumeria graminis. I demonstrate that structural elucidation of CNLs in complex with their cognate effectors, and investigation of the interface between the two, can guide the rational design of CNLs to broaden effector recognition specificity. To this end, I have developed and present here a versatile and robust protocol for the purification of proteins from leaves of Nicotiana benthamiana, which has been successfully applied to a range of proteins and structural studies. Taken together, I show that experimentally resolved receptor effector structures remain indispensable for understanding crop-pathogen interactions and aiding the design of NLRs with expanded effector recognition capability to enhance resistance to crop diseases.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Lawson, Aaron W. lawson.w.aaron@gmail.com orcid.org/0000-0001-8164-2555 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-742852
Date:	2024
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Außeruniversitäre Forschungseinrichtungen > MPI for Plant Breeding Research
Subjects:	Life sciences
Uncontrolled Keywords:	Keywords Language Cryo-EM English Effectors English Plant NLR receptors English
Date of oral exam:	7 November 2024
Referee:	Name Academic Title Schulze-Lefert, Paul Prof. Dr. Parker, Jane Prof. Dr.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/74285