The immune system helps plants resist pathogen infections and has been well studied. However, it becomes increasingly clear that enhancing defense comes at a cost, as plants slow down growth even if the infection is successfully combatted. In this project, you will investigate the poorly understood process of how plants control their growth during and after an immune response. You will capitalise on the available extensive lettuce gene expression and high-throughput phenotyping datasets.
Your job Current projections show that the incidence of diseases on crops will increase in the coming decades, and thus, conceptually new strategies, beyond strengthening the immune system, are needed to ensure the resilience of future crops. It turns out that plants slow down their growth during and after an immune response regardless of the disease intensity. However, how these growth processes are regulated in plants is unclear. In this curiosity-driven PhD project, you will uncover the genetic and molecular basis of plant growth during and after an immune response. With this knowledge, one could develop approaches that reduce this tradeoff in crop growth. You will primarily work with lettuce (
Lactuca sativa), but conservation of the deduced concepts can be investigated in other plant species, such as
Arabidopsis thaliana.
Your project will capitalise on two types of datasets generated during the
LettuceKnow programme. The first dataset includes large and dense time-course RNAseq experiments, where we activated the lettuce immune system and tracked the transcriptome changes over several hours. The second dataset includes high-throughput digital phenotyping data for the growth of ~180 lettuce varieties in the presence of defense hormones and after their removal (the recovery phase). This dataset was obtained with the
Netherlands Plant Ecophenotyping Center (NPEC).
In the first phase of the project, you will utilise bioinformatics, genome-wide association mapping (GWAS), and machine learning techniques to identify new players of plant growth during and after an immune response. You will validate the genetic leads, such as transcription factors (TFs), identified in our earlier research. In the second phase of the project, you will work on the functional validation and characterization of the identified regulators of immunity-conditioned growth (e.g., TFs) using CRISPR-Cas gene editing and alteration of gene expression in lettuce and Arabidopsis. For selected targets, you will use quantitative proteomics and chromatin-protein interaction assays to gain insights into the activity of protein complexes driving growth during and after an immune response. Similarly, high-throughput digital phenotyping of mutants and overexpression lines in NPEC can be used to investigate their impact on inferred regulatory pathways.
As a PhD candidate, you will be responsible for designing and conducting experiments behind the computer and in the laboratory. You will also be involved partially in supervising BSc and MSc students and, occasionally, sharing your expertise in BSc courses. This will help you learn about supervision and teaching and open additional perspectives for the next career steps.
Your professional development as a researcher will be supported by a supervision team of 2-3 people. All needed expertise is present in our research group or through the collaborators. At the start of the project, you will work together with an experienced PhD candidate and postdoc, that will give you a productive start. Although there are no industry partners involved in the project, you will have opportunities to discuss your professional development and future career steps with a mentor from an industry or other area of your choice.
We currently have another PhD position on growth-immunity tradeoffs available in Dmitry Lapin’s team. For more information about this position, check out our website.