Life histories of hosts and pathogens predict patterns in tropical fungal plant diseases

Summary Plant pathogens affect the fitness of their hosts and maintain biodiversity. However, we lack theories to predict the type and intensity of infections in wild plants. Here we demonstrate using fungal pathogens of tropical plants that an examination of the life histories of hosts and pathogens can reveal general patterns in their interactions. Fungal infections were more commonly reported for light‐demanding than for shade‐tolerant species and for evergreen rather than for deciduous hosts. Both patterns are consistent with classical defence theory, which predicts lower resistance in fast‐growing species and suggests that the deciduous habit can reduce enemy populations. In our literature survey, necrotrophs were found mainly to infect shade‐tolerant woody species whereas biotrophs dominated in light‐demanding herbaceous hosts. Far‐red signalling and its inhibitory effects on jasmonic acid signalling are likely to explain this phenomenon. Multiple changes between the necrotrophic and the symptomless endophytic lifestyle at the ecological and evolutionary scale indicate that endophytes should be considered when trying to understand large‐scale patterns in the fungal infections of plants. Combining knowledge about the molecular mechanisms of pathogen resistance with classical defence theory enables the formulation of testable predictions concerning general patterns in the infections of wild plants by fungal pathogens. Contents Summary 1106 I. Plant pathogens in tropical ecosystems 1107 II. Questions and patterns 1109 III. Pathogens as destructors and constructors 1109 IV. Questions and patterns 1110 V. Endophytes as a reservoir of necrotrophic pathogens? 1111 VI. Plant resistance to necrotrophs and biotrophs 1111 VII. Plant defence theory 1113 VIII. General patterns in fungal infections of tropical plants 1114 IX. Explaining patterns 1114 X. Conclusions and outlook 1116 Acknowledgements 1117 References 1117