Primary supervisor: Dr Estrella Luna-Diez, University of Birmingham

Non-academic partner: Dr Emmanouil Domazakis, Enza Zaden

Project description

Rationale

Fruit decay due to postharvest diseases can claim up to 50% of total crop production. Pesticides can control these diseases but their use postharvest is extremely limited due to toxicity. Therefore, new control strategies are required. Research that exploits the plant’s immune system to confer protection against diseases provides a sophisticated source for future Integrated Disease Management (IDM).

Preliminary data

We have discovered that the resistance of tomato fruit can be improved through priming of plant defence mechanisms. Priming treatments are performed with the broad-spectrum defence elicitor β-aminobutyric acid (BABA). Priming can be long-lasting, be transmitted to following generations and its durability can be associated with epigenetic changes, such as DNA methylation, that ultimately alter gene expression. Our experiments have demonstrated that (i) priming seedlings with BABA results in long-lasting protection of the fruit; (ii) priming by BABA can be achieved using commercial strategies such as grafting; and (iii) mobile signals and DNA methylation mediate long-lasting BABA priming.

Vision

This PhD project will focus on understanding the molecular mechanisms of the ways of action of these mobile signals and will identify targets for exploiting long-lasting fruit priming in other Solanaceae crops.

Objectives

Objective 1. To identify the triggers of priming. We will perform grafting in different commercial tomato cultivars and other Solanaceae species (including aubergine) and will test resistance phenotypes. Different omics analyses (i.e small RNA (sRNA) sequencing, transcriptomics and metabolomics) will be performed to identify mobile signals.

Objective 2. To test the role and function of mobile signals. The molecular mechanisms of action of mobile signals will be tested by different techniques based on genetic engineering (e.g. overexpression, knock-down and metabolite inhibitors).

Objective 3. To assess the durability of the priming response. Multiple transgenerational experiments will be performed with heterograft combinations obtained in Objective 1. Methylomes will be used to identify global differences in DNA methylation between combinations that transfer priming and the ones where priming is not durable.

Expected outcome

With this PhD project, we will expand in our understanding of long-lasting priming from a metabolite perspective to an epigenetic horizon to obtain a comprehensive analysis of durable resistance.

Candidates are encouraged to contact Dr Estrella Luna-Diez to discuss the project before applying if they wish to.