Enhancing Crop Resilience and Productivity: Investigating relationships between Plant Photosynthetic Efficiency, Pest Defence, and Microbial Interacti

To meet the increasing demands for agricultural produce by 2050 we must double agricultural output from 2005 levels; however, this will require significant improvements in food production. Increasing plant's photosynthetic efficiency offers a largely unexploited potential for boosting crop yields. As such, there is currently a significant effort to identify and breed new cultivars of key crops with increased photosynthetic efficiency to increase productivity using existing variability within crop germplasms and GM approaches. Yet, solely increasing yield potential will not be sufficient to ensure food security.

Biotic and abiotic stress can have a significant impact on crop yield and since plant responses to these challenges may alter with changes in the plant's photosynthetic efficiency, these factors need to be addressed simultaneously. Little is known about how increased capacity for CO2 assimilation (through increased photosynthetic efficiency) affects plant's direct and indirect defences.

Improved plant health is often associated with increased pest performance, increasing the need for robust plant defences. A promising new strategy is to inoculate plants with defence-inducing rhizobacteria before pest arrival, which triggers a quicker and stronger defence response against arriving pests. The interplay between these rhizobacteria, plant photosynthetic capacity and impact on pest control is a critical knowledge gap in current plant research.

This project aims to assess how increased photosynthetic capacity alters plant defence response to pest infestation in potato (Solanum tuberosum) and a brassica model species (Arabidopsis thaliana). Sap-feeding aphids (Myzus persicae) and leaf-chewer caterpillars (Spodoptera spp.) will be the focus of the project given their wide host range and importance to the UK economy.

We will induce plant defences using the common soil bacterium and bioprotectant Bacillus subtilis, known to improve plant yields and reduce aphid and caterpillar performances. Given the significance of the yield losses pest can be responsible for, and potential benefits of microbial inoculations, understanding the impact that changes in primary metabolism could have in the plant-soil bacterium-pest relations is of critical importance.

Objectives

1. Measuring plant photosynthetic rates and C/N ratios and resulting pest performance on plants with different photosynthetic capacities, across pest and microbial inoculation treatments.

2. Measuring levels of targeted plant hormone signalling (defensive) compounds and volatile to decipher the mechanism of interactions among the species and how changes in photosynthetic capacity might alter these.

3. To undertake a field survey to evaluate the biodiversity and abundance of natural predators for potato pests across low and high photosynthesis cultivars