Programming Long-Lasting Immunity in Tomato

About the project

About the Project Plants can acquire an enhanced capacity to respond to future stress following an initial stimulus, a phenomenon known as defence priming. This form of immune memory has considerable potential for improving crop resilience, but we still do not understand why long-lasting priming can only be established during particular stages of plant development, or how an early signal is stored for weeks after the original treatment has disappeared. Our recent work in tomato provides an exciting system in which to address this question. Treatment with the defence-priming compound β-aminobutyric acid (BABA) during an early developmental window produces resistance that persists into later development and fruit. The same treatment at later developmental stages induces only short-lived resistance. We have also identified mobile small RNAs associated with graft-transmissible priming, including 24-nucleotide sRNAs linked to genes that subsequently show stronger transcriptional responses to pathogen challenge. Intriguingly, this long-term transcriptional priming is not explained by stable changes in DNA methylation at the primed genes. This raises a fundamental question: how is a transient early-life signal converted into durable immune memory? This PhD will investigate how developmental stage, sRNA signalling and chromatin regulation interact to establish long-lasting immune priming in tomato. The project will combine plant pathology, grafting, genetics, molecular biology and functional genomics, using the rapid-cycling MicroTom tomato system and unique epigenetic mutant resources. The project will initially define the developmental window in which durable BABA-induced resistance can be established and test candidate regulators emerging from our existing developmental transcriptomic datasets. The student will then use tomato epigenetic mutants, including Kryptonite and CMT3-related material, to determine if specific chromatin pathways are required for the establishment and transmission of priming, and if altered epigenetic regulation changes the developmental competence to acquire long-lasting resistance. Reciprocal grafting experiments will further distinguish effects on the production of a mobile priming signal from effects on its reception in distant tissues. A further objective will examine how mobile small RNAs are translated into a persistent transcriptional state. The student will use genomic and chromatin approaches, potentially including small-RNA sequencing, transcriptomics and assays of chromatin accessibility or histone states, to identify molecular features that distinguish transient from long-lasting priming. Comparative grafts between genetically distinct tomato backgrounds may also enable the origin and movement of candidate signals to be tracked. The student will be based at the University of Birmingham and will work within a collaborative team spanning plant immunity, epigenetics and genomics. The project is expected to include research visits/secondments to Rothamsted Research to work with specialist tomato epigenetic resources and genomic expertise. This project is ideally suited to a student interested in plant molecular biology, plant-pathogen interactions, epigenetics, RNA biology or functional genomics. It offers training across experimental plant biology and cutting-edge molecular approaches while addressing a fundamental question in plant biology: how does developmental history determine a plant’s capacity to remember stress? To apply, send your CV and Cover letter to the supervisor e.lunadiez@bham.ac.uk before the 8 th November 2026.

Research areas