Primary Supervisor: Dr Andrew Beacham, Department of Agriculture & Environment
Secondary supervisor: Dr Joe Roberts (HAU), Professor Jim Monaghan (HAU), Dr Graham Teakle (Warwick)
PhD project title: How Do Crops Respond to Combined Biotic and Abiotic Stress? – Implications for Integrated Pest Management
University of Registration: Harper Adams University
Plants respond to different stresses such as pests and temperature in different ways. We are now discovering that responses to combined stress differ from those to single stresses. The effect of combined biotic (biological) and abiotic (environmental) stresses is an important and emerging area of study. Biotic stress can influence a plant’s response to abiotic stress and vice versa (Atkinson and Urwin, 2012).
The key fresh produce crop lettuce (Lactuca sativa) suffers from a range of biotic pressures including the lettuce-currant aphid, Nasonovia ribisnigri and abiotic stresses such as drought. We have phenotyped lettuce germplasm belonging to the Vegetable Genetic Improvement Network (VeGIN) Diversity Fixed Foundation Set (DFFS), revealing significant resilience variation against N. ribisnigri (Walley et al., 2017) and abiotic stress (manuscript in preparation). We hypothesise that the response to combined abiotic-biotic stress will similarly also depend upon host genotype.
Furthermore, agronomic and environmental issues, such as the emergence of pest and pathogen resistance against and removal of approval for many chemical control products, are necessitating the investigation of novel and sustainable biocontrol approaches in agriculture (Ciancio et al., 2016), which may form part of integrated pest management (IPM) approaches.
Endophytic fungi are receiving increased research attention as biocontrol options (Jaber and Ownley, 2017). Endophytic Trichoderma species have recently been shown to induce resistance to pests (Rodriguez-Gonzalez et al., 2016; Coppola et al., 2017; Contreras-Cornejo et al., 2018a) and increase their parasitism by natural enemies (Contreras-Cornejo et al., 2018b). In lettuce, Trichoderma spp. can increase resistance to drought (Saia et al., 2019). However, the lettuce-Trichoderma system remains relatively under-studied e.g. no investigation of Trichodermaefficacy against aphids in lettuce has been made to date.
We hypothesise that the response of lettuce to Trichoderma application for the purpose of enhancing resistance to biotic and abiotic stress may also depend upon host genotype.
- Using available data, identify extreme lines (most and least resilient) within the lettuce DFFS for resistance to ribisnigri and abiotic stress at the transplant stage.
- In these lines, investigate the effect of host genotype on response to single and combined biotic and abiotic stress (aphids and drought) using modifications to the established DFFS phenotyping methodologies.
- For lettuce-stress combinations exhibiting the strongest responses (resistant or susceptible), the interaction will be investigated further using a timeline of host transcriptomic and hormonal responses, host volatile organic compound (VOC) profile, aphid feeding behaviour, fecundity and generation time and parasitism rate of aphids by parasitic wasps.
- Extreme lettuce lines will then be inoculated with commercially available Trichoderma products and treatment efficacy against single and combined biotic and abiotic stress (aphids and drought) examined.
- Atkinson and Urwin (2012) J Exp Bot 63(10): 3523-3544. Ciancio et al., (2016) Front Microbiol https://doi.org/10.3389/fmicb.2016.01620. Jaber and Ownley (2017) Biol Control 107: 50-59. Contreras-Cornejo et al., (2018a) Appl Soil Ecol 124: 45-53. Contreras-Cornejo et al., (2018b) Soil Biol Biochem 122: 196-202. Coppola et al., (2017) Insect Sci 24(6): 1025-1033. Rodriguez-Gonzalez et al., (2016) Environ Monit Assess 189: 12. Saia et al., (2019) Scientia Hort 256: 108595. Walley et al., (2017) Mol Breeding 37: 4. D’Amico et al., (2008) Mycol Res 112(1): 100-107.
BBSRC Strategic Research Priority: Sustainable Agriculture and Food: Plant and Crop Science
Techniques that will be undertaken during the project:
Polymerase chain reaction (PCR) and molecular cloning, microbiology, whole plant bioassays using pests, collection and analysis of plant VOCs using gas chromatography-mass spectrometry (GC-MS), electrophysiology for recording aphid feeding, RT-qPCR and plant hormone analysis.
In addition, masterclasses and mini-projects which will be available to the student will include: bioinformatics, programming statistical analysis using R, hydroponic culture, vertical and urban farming, integrated pest management and insect behavioural studies such as olfactometry.
Contract: Dr Andrew Beacham, Harper Adams University