Research Article | Open Access

Volume 2024 |Article ID 0214 | https://doi.org/10.34133/plantphenomics.0214

High-Resolution Disease Phenotyping Reveals Distinct Resistance Mechanisms of Tomato Crop Wild Relatives against Sclerotinia sclerotiorum

Severin Einspanier,¹ Christopher Tominello-Ramirez,¹ Mario Hasler,² Adelin Barbacci,³ Sylvain Raffaele,³ and Remco Stam ¹

¹Department of Phytopathology and Crop Protection, Institute of Phytopathology, Faculty of Agriculturaland Nutritional Sciences, Christian-Albrechts-University, 24118 Kiel, Germany
²Lehrfach Variationsstatistik,Faculty of Agricultural and Nutritional Sciences, Christian-Albrechts-University, Kiel, 24118 Kiel, Germany
³Laboratoire des Interactions Plantes Microorganismes Environnement (LIPME), INRAE, CNRS, CastanetTolosan Cedex, France

Abstract

Besides the well-understood qualitative disease resistance, plants possess a more complex quantitative form of resistance: quantitative disease resistance (QDR). QDR is commonly defined as a partial but more durable form of resistance and, therefore, might display a valuable target for resistance breeding. The characterization of QDR phenotypes, especially of wild crop relatives, displays a bottleneck in deciphering QDR’s genomic and regulatory background. Moreover, the relationship between QDR parameters, such as infection frequency, lag-phase duration, and lesion growth rate, remains elusive. High hurdles for applying modern phenotyping technology, such as the low availability of phenotyping facilities or complex data analysis, further dampen progress in understanding QDR. Here, we applied a low-cost (<1.000 €) phenotyping system to measure lesion growth dynamics of wild tomato species (e.g., Solanum pennellii or Solanum pimpinellifolium). We provide insight into QDR diversity of wild populations and derive specific QDR mechanisms and their cross-talk. We show how temporally continuous observations are required to dissect end-point severity into functional resistance mechanisms. The results of our study show how QDR can be maintained by facilitating different defense mechanisms during host–parasite interaction and that the capacity of the QDR toolbox highly depends on the host’s genetic context. We anticipate that the present findings display a valuable resource for more targeted functional characterization of the processes involved in QDR. Moreover, we show how modest phenotyping technology can be leveraged to help answer highly relevant biological questions.