Daily fluctuations in leaf temperature modulate the development of a foliar pathogen - INRAE - Institut national de recherche pour l’agriculture, l’alimentation et l’environnement Access content directly
Journal Articles Agricultural and Forest Meteorology Year : 2022

Daily fluctuations in leaf temperature modulate the development of a foliar pathogen

Abstract

Thermal ecology studies on the ecophysiological responses of organisms to temperature involve two paradigms: physiological rates are driven by body temperature and not directly by the environmental temperature, and they are largely influenced not only by its mean but also its variance. These paradigms together have been largely applied to macro invertebrates and vertebrates but rarely to microorganisms. According to these paradigms, foliar fungal pathogens are expected to respond directly to the fluctuations in leaf temperature, rather than in air temperature. We determined experimentally the impact of two patterns of leaf temperature variation of equal mean temperature, but differing in their daily amplitude, on the development of Zymoseptoria tritici, a fungus infecting wheat leaves. The highest daily thermal amplitude resulted in two detrimental effects for the pathogen fitness: an increase in the length of the latent period, i.e. the ‘generation time’ of the fungus when infecting its host plant, and a decrease in the density of fruiting bodies on the leaves. We discussed these empirical results, mainly the impact of both the daily thermal amplitude and the fluctuation frequency on the pathogen development in planta, in the light of the mathematical effect of the integration of non-linear functions. We concluded that it is necessary to take into account daily leaf temperature amplitudes to improve our understanding and prediction of the development of foliar fungal pathogens and other micro-organisms living in the phyllosphere in the climate change context.

Dates and versions

hal-03685073 , version 1 (01-06-2022)

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Frédéric Bernard, Michaël Chelle, Alain Fortineau, Ons Riahi El Kamel, Sylvain Pincebourde, et al.. Daily fluctuations in leaf temperature modulate the development of a foliar pathogen. Agricultural and Forest Meteorology, 2022, 322, pp.109031. ⟨10.1016/j.agrformet.2022.109031⟩. ⟨hal-03685073⟩
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