Thermography Applied to the Assessment of Podosphaera xanthii Infection in Susceptible Melon Plants

Abstract

Powdery mildew, a disease caused by the biotrophic fungus Podosphaera xanthii, is one of the most destructive diseases affecting melon crops worldwide. This pathogen causes alterations in the physiology of the host plant even before visible symptoms appear, which in turn can be detected using non-invasive imaging techniques. In this piece of work, infrared thermography was used to evaluate the temperature dynamics of melon leaves infected with P. xanthii during the first 72 h after infection. Infected leaves showed a significant decrease in temperature compared to mock-controls from 18.5 hpi onwards, before the appearance of visible mycelium. This temperature difference between mock-control and P. xanthii-infected melon leaves remained significant throughout the experiment, suggesting a sustained disruption of water-balance regulation caused by the fungus. This imbalance could be linked to haustorium-mediated interference with stomatal function or epidermal osmotic homeostasis. Overall, these results highlight thermography as a powerful and sensitive tool for detecting early physiological responses during P. xanthii infection of melon leaves. Therefore, thermography could be used as a valuable complement to ‘omics’ and other image-based phenotyping methods, helping to provide a comprehensive view of the responses that different diseases trigger in host plants.

Plant phenotyping relevance

メロン葉の感染に伴う温度変化を赤外線サーモグラフィーで非侵襲的に測定し、可視症状前の病態・生理状態を評価する方法の適用が中心である。

Code and data availability

The paper reports thermographic phenotyping of Podosphaera xanthii-infected melon leaves, but no public dataset, image repository, code, or trained model is deposited. The Data Availability Statement states the data are available only upon reasonable request to the corresponding author, so any qualifying asset requires

No evidence-backed public reproduction asset is currently recorded.