Derevnina Group: Defining the transcriptional regulation and spatiotemporal deployment of helper NLR immune receptors
Supervisor
Dr Lida Derevnina
Importance of Research
Plants use intracellular nucleotide-binding leucine-rich repeat proteins (NLRs) to detect pathogen-derived molecules, including virulence proteins known as effectors, and activate defence. Many NLRs function within immune networks in which sensor NLRs detect pathogen activity and signal through downstream helper NLRs. Because multiple resistance pathways can converge on a limited number of helpers, their abundance, timing and spatial distribution are likely to be major determinants of immune capacity. Despite their central role, little is known about how helper NLR genes are transcriptionally regulated or how variation in their expression influences disease resistance. Understanding these regulatory mechanisms could provide new opportunities to strengthen crop immunity while avoiding the growth penalties associated with constitutive or excessive immune activation.
Project Summary
This project will determine how helper NLR expression is regulated across plant tissues and infection conditions, and how this regulation shapes immune function. The NRC immune network of solanaceous plants will provide a genetically tractable model system. The project will integrate three complementary areas of investigation. First, the spatiotemporal expression of multiple helper NRC genes will be characterised across tissues, developmental stages and pathogen interactions. Promoter–reporter lines, transcriptomic datasets and targeted expression analyses will be used to determine whether helper NLRs are constitutively expressed, tissue specialised or induced during infection. Second, the regulatory architecture controlling helper NLR expression will be defined. The NRC4 promoter will be used as a mechanistic case study in Nicotiana benthamiana. Promoter truncations, targeted deletions, mutagenesis and comparative sequence analysis will identify conserved cis-regulatory elements and candidate transcription-factor binding sites. Candidate regulatory proteins will then be prioritised and experimentally validated. Finally, the functional consequences of altering helper NLR expression will be tested. Promoter editing, inducible expression or tissue-specific expression approaches will be used to determine how helper abundance and deployment affect sensor NLR signalling, pathogen resistance and plant fitness. Together, this work will establish how transcriptional regulation determines the capacity of plant immune networks.
What the successful applicant will do
The successful applicant will use molecular cloning, promoter–reporter assays, plant transformation, comparative genomics, transcriptomics, microscopy and plant–pathogen assays. They will gain experience in both computational and experimental approaches while investigating fundamental questions in immune-gene regulation and crop disease resistance.