No abstract

The version presented here may differ from the published version. If citing, you are advised to consult the published version for pagination, volume/issue and date of publication Chaloner et al.

The ecological niche of a species can be conceptualized as a volume in multidimensional space, where each dimension describes an abiotic condition or biotic resource. The shape and size of this volume strongly determines interactions among species and influences their global distribution, but the geometry of the niche is poorly understood. Here, we analyse temperature response functions and host plant ranges for hundreds of fungi and oomycetes. We demonstrate that niche specialization is independent on abiotic and biotic axes, that host interactions restrict fundamental niche breadth to form the realized niche, and that both abiotic and biotic niches show limited phylogenetic constraint. Such niche adaptability makes plant pathogens a formidable threat to agriculture and forestry.

No abstract

7Global food security is strongly determined by crop production. Climate change will not only 8 affect crop yields directly, but also indirectly via the distributions and impacts of plant 9 pathogens that can cause devastating production losses. However, the likely changes in 10 pathogen pressure in relation to global crop production are poorly understood. Here we show 11 that disease risk for 79 fungal and oomycete crop pathogens will closely track projected yield 12 changes in 12 major crops over the 21 st Century. For most crops, yields are likely to increase 13 at high latitudes but disease risk will also grow. In addition, the USA, Europe and China will 14 experience major changes in pathogen assemblages. In contrast, while the tropics will see 15 little or no productivity gains, the disease burden is also likely to decline. The benefits of 16 yield gains will therefore be tempered by the increased burden of crop protection. 17 Main text 18Plant pests and pathogens exert a growing burden on crop production around the world 1,2 . 19The burden can be measured directly in yield losses or indirectly in the social, environmental 20 and economic costs of control 1 . Like all species, crop pests and pathogens have particular 21 tolerances to, or requirements for, particular environmental conditions 3 . These tolerances 22 define their ecological niche, which determines the geographical regions and periods of the 23year that allow pests and pathogens to proliferate and attack crops 3 . As climate changes, 24 suitable conditions for pest outbreaks shift in time and space, altering the threats that farmers 25 face and the management regimes required for their control 4 . Modelling the pattern and 26 process of future changes in pest and pathogen burdens is therefore a key component in Latitudinal range shifts of pests and pathogens are expected as the planet warms and 29 populations track their preferred temperature zones 4 . Spatial movements in geographical 30 distributions and temporal shifts in phenologies of wild populations are among the clearest 31 signs of anthropogenic global warming 6 . Though distribution data for crop pests and 32 pathogens are noisy and incomplete 5 , similar changes have been detected for hundreds a 33 species of pests and pathogens over recent decades 7 . Increasing burdens of insect pests at 34 high latitudes, and decreasing burdens at low latitudes, have been projected using ecological 35 niche models (ENM) 8 . ENMs attempt to reconstruct the environmental tolerances of species 36 from contemporary climates within the observed species range using statistical models 9 . 37Alternatively, species' responses to microclimate can be directly measured, and these 38 responses incorporated into physiologically-based models of species performance 10 . Such 39 mechanistic models are commonly used to project future crop yields 11 , and models have also 40 been developed for some plant diseases 12,13 . However, we know little about how plant 41 disease pressure is likely to change in future, nor h...

The ecological niche can be thought of as a volume in multidimensional space, where each dimension describes an abiotic condition or biotic resource required by a species. The shape, size, and evolution of this volume strongly determine interactions among species and influence their current and potential geographical distributions, but the geometry of niches is poorly understood. Here, we analyse temperature response functions and host plant ranges for hundreds of potentially destructive plant-associated fungi and oomycetes. We demonstrate that niche specialization is uncorrelated on abiotic (i.e. temperature response) and biotic (i.e. host range) axes, that host interactions restrict fundamental niche breadth to form the realized niche, and that both abiotic and biotic niches show limited phylogenetic constraint. The ecological terms ‘generalist’ and ‘specialist’ therefore do not apply to these microbes, as specialization evolves independently on different niche axes. This adaptability makes plant pathogens a formidable threat to agriculture and forestry.

We present a new mechanistic model for predicting Septoria tritici blotch (STB) disease, parameterized with experimentally derived data for temperature- and wetness-dependent germination, growth and death of the causal agent, Zymoseptoria tritici . The output of this model (A) was compared with observed disease data for UK wheat over the period 2002–2016. In addition, we compared the output of a second model (B), in which experimentally derived parameters were replaced by a modified version of a published Z. tritici thermal performance equation, with the same observed disease data. Neither model predicted observed annual disease, but model A was able to differentiate UK regions with differing average disease risks over the entire period. The greatest limitations of both models are: broad spatial resolution of the climate data, and lack of host parameters. Model B is further limited by its lack of explicitly defined pathogen death, leading to a cumulative overestimation of disease over the course of the growing season. Comparison of models A and B demonstrates the importance of accounting for the temperature-dependency of pathogen processes important in the initiation and progression of disease. However, effective modelling of STB will probably require similar experimentally derived parameters for host and environmental factors, completing the disease triangle. This article is part of the theme issue ‘Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes’. This issue is linked with the subsequent theme issue ‘Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control’.

The methodological development of a series of domino or cascade reactions affording a series of N‐heterocycles is described. The rapid formation of these ring systems is in each case associated with the incorporation of a Heck reaction at either an early or a late stage of the domino process. A range of catalytic conditions and substrate modifications for optimisation of domino Tsuji–Trost/Heck, Buchwald–Hartwig/Heck and Heck/carbopalladation reaction sequences are reported.