Leaf surface properties impact pathogenic and commensal microbial populations of the barley phyllosphere
This is one of the funded projects for our 2025 Undergraduate vacation bursary, click here to return to the list of 15 projects.
| This project is going to be… | Experimental (lab/field based) |
| Institute | The James Hutton Institute |
| Project supervisor | Dr. Lorena Rangel |
| Title of Project | Leaf surface properties impact pathogenic and commensal microbial populations of the barley phyllosphere |
| Date of Project Commencement | 23 June 2025 |
| Duration (weeks) | 8 |
| Brief Description of Project | The barley leaf surface, or phyllosphere, harbours a diversity of microorganisms, including bacteria and fungi, which interact with the plant and each other. Changes in the epicuticular wax composition of leaf surfaces can influence microbial colonisation, as this wax layer serves as the first barrier for most microbes, including pathogens. While plant genotype has been shown to affect disease severity in other pathosystems, its role in influencing microbial diversity and pathogen establishment is less understood.This project aims to investigate the impact of the epicuticular wax layer on plant fitness, leaf-associated microbial populations, and the establishment of the barley scald pathogen, Rhynchosporium commune, in field-grown barley. We hypothesize that barley genotype influences disease severity both indirectly—by altering microbial colonisation—and directly—by modifying leaf surface composition. Relevance:The epicuticular wax layer may offer an innovative solution in integrated pest management. By selecting cultivars with different wax compositions, we may be able to influence microbial colonisation in the phyllosphere, potentially reducing disease susceptibility, improving plant fitness, and limiting pathogen establishment. Aims:1. To characterize the fungal and bacterial communities in the barley phyllosphere throughout the growing season on wild-type barley and epicuticular mutants. 2. To quantify R. commune biomass over the growing season on wild-type barley and epicuticular mutants.Methodology: The spring barley variety Bowman and three isogenic epicuticular wax mutants will be sown in April 2025 at a James Hutton Institute-designated field with high R. commune disease pressure. Total above-ground tissues will be sampled every three weeks starting in June. Leaf samples will undergo culture-independent fungal ITS and bacterial 16S community profiling via MinION sequencing in-house. Additionally, R. commune biomass will be quantified through qPCR of gDNA extracted from leaf samples.Supervision and Student Benefits: The project will be hosted by the James Hutton Institute in Dundee, Scotland, a leading research institute in plant science and agricultural advancements. The student will be supervised by the project lead with close guidance during fieldwork, data collection, and laboratory analysis. Regular meetings will ensure continuous support, while hands-on mentorship will be provided throughout all stages of the project—from field sampling to microbiome profiling and pathogen quantification. They will develop skills in environmental sampling, microbial community analysis, and molecular techniques, including DNA extraction, sequencing, and pathogen quantification. This experience will provide exposure to both field and lab-based environmental research, offering a comprehensive understanding of research institute operations and plant-pathogen interactions.Recommended reading for the project Mechan-Llontop, M. E., Mullet, J., & Shade, A. (2023). Phyllosphere exudates select for distinct microbiome members in sorghum epicuticular wax and aerial root mucilage. Phytobiomes Journal, 7(2), 184-197. https://doi.org/10.1094/PBIOMES-08-22-0046-FIReisberg, E. E., Hildebrandt, U., Riederer, M., & Hentschel, U. (2013). Distinct phyllosphere bacterial communities on Arabidopsis wax mutant leaves. PLoS One, 8(11), e78613. https://doi.org/10.1371/journal.pone.0078613 Li, C., Haslam, T.M., Krüger, A., Schneider, L.M., Mishina, K., Samuels, L., Yang, H., Kunst, L., Schaffrath, U., Nawrath, C. and Chen, G. (2018). The β-ketoacyl-CoA synthase Hv KCS1, encoded by Cer-zh, plays a key role in synthesis of barley leaf wax and germination of barley powdery mildew. Plant and Cell Physiology, 59(4), 811-827. https://doi.org/10.1093/pcp/pcy020 |
