Characterisation of the Arabidopsis thaliana leucine-rich repeat receptor kinase subfamily XII in immune signalling.

Rhodes, Jack (2019) Characterisation of the Arabidopsis thaliana leucine-rich repeat receptor kinase subfamily XII in immune signalling. Doctoral thesis, University of East Anglia.

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Plant cells employ cell surface-localised receptors in order to perceive perturbations in their environment. One such context, central to plant survival, is the recognition of potential pathogens through pattern recognition receptors (PRRs). Upon recognition of apoplastic molecular patterns indicative of danger, PRRs induce pattern-triggered immunity. These molecular patterns can be of non-self (pathogen-associated molecular patterns; PAMPs) or modified-self (danger-associated molecular patterns; DAMPs) origins. Recognition of many PAMPs is lineage specific due to the phylogenetically restricted distribution of the cognate receptors. In general, PRRs can be transferred between angiosperm genomes to confer PAMP-recognition and induce quantitative, broad-spectrum disease resistance. As such, non-crop genomes represent a potential reservoir of exploitable PRRs to engineer resistance. Currently, this approach is constrained by the limited number of characterised PRRs. With this in mind, I sought to characterise additional members of the leucine-rich repeat receptor kinase subfamily XII from Arabidopsis thaliana; a known PRR-containing clade. I generated a range of genetic resources to screen a range of pathogens for gain- or loss-of-resistance. Within this subfamily, I focused on MIK2, whose mutants show defects in pollen tube guidance, salt stress tolerance, cell wall integrity sensing, Fusarium oxysporum resistance and root skewing. Our data revealed that loss of MIK2 leads to defects in basal ROS production and transcriptomic homeostasis. Moreover, we showed that mik2 mutants are differentially affected in elicitor-induced reactive oxygen species production, revealing an undescribed elicitor-based dichotomy. Through this work, I identified the recently described DAMP SCOOP12 is a likely ligand for MIK2. Furthermore, analysis of transcriptional changes in mik2 revealed a novel phytocytokine-like peptide, which is transcriptionally upregulated in mik2. The insights gained through this work further our understanding of how plants recognise and potentiate danger signals and integrate these into physiological responses.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Chris White
Date Deposited: 24 Oct 2022 10:58
Last Modified: 24 Oct 2022 10:58


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