How does the circadian clock regulate disease resistance?

Lead Research Organisation: University of York
Department Name: Biology

Abstract

This project investigates how a plant's circadian clock (molecular clock) alters
its susceptibility to infection at different times of the day. It is an exciting
opportunity to work in a new field, learn a range of modern experimental and
computational skills and join an active, enthusiastic research group. The
research will involve genetics, molecular biology, proteomics, high-throughput
yeast-2-hybrid, transcriptomics, pathogen infection assays, genomics, gene
editing and computational biology.
Almost all living organisms ranging from cyanobacteria to plants and animals
possess a circadian clock. The circadian clock generates an ~24 h rhythm that is
set by daily cycles of light and temperature. This enables organisms to
anticipate regular daily events such as dawn and dusk. For plants, which cannot
move, the circadian clock is particularly important to synchronise its
metabolism with the environment. Recently it was discovered that the clock
also impacts plant immunity; plants inoculated at different times of the day
show differing susceptibility to pathogens. We demonstrated that Arabidopsis
plants showed greater resistance to Botrytis cinerea, a fungal pathogen, after
inoculation at dawn compared to inoculation during the night (Ingle et al. 2015
Plant Journal). The difference in susceptibility when the plants are inoculated at
dawn or night is driven by the plant circadian clock.
The plant immune response involves significant changes in gene expression
regulated by transcription factors within a regulatory network. After
inoculation at dawn this defence network is activated faster leading to more
effective resistance against the pathogen. Incredibly a four-hour difference in
activation of the defence response leads to a dramatic difference in disease
progression. Timing is everything! We have found that a single protein in a
hormone (jasmonic acid) signaling pathway controls the change in disease

susceptibility during the day. This protein, JAZ6, works by targeting
transcription factors.
We now want to ask how does the clock via JAZ6 control disease resistance?
How broad is JAZ6-dependent disease resistance? What transcription factors in
the regulatory network does JAZ6 target? How do changes in the defence
network cause increased disease resistance? What is the timing of JAZ6
activity?
Critically we want to investigate whether we can alter JAZ6 in crop plants to
activate the defence network faster and enhance disease resistance. JAZ6
orthologues are present in Brassica, lettuce and tomato (all crops infected by B.
cinerea) and we will use gene editing to test whether JAZ6 is a clock-immunity
regulator in these crops.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
BB/M011151/1 01/10/2015 30/09/2023
2113020 Studentship BB/M011151/1 01/10/2018 30/09/2022 James Forsythe