ABSTRACT
As sessile organisms, plants are constantly challenged by a dynamic
growing environment. This includes fluctuations in temperature, water
availability, light levels, and atmospheric conditions. In concert with
changes in abiotic conditions, plants experience changes in biotic
stress pressures, including plant pathogens, viruses, and herbivores.
Human-induced increases in atmospheric carbon dioxide
(CO2) levels have led to alterations in plant growth
environments that challenge their productivity and nutritional quality.
Additionally, it is predicted that climate change will alter the
prevalence and virulence of plant pathogens, further challenging plant
productivity. A knowledge gap exists in the complex interplay between
plant responses to biotic and abiotic stress conditions. Closing this
gap is crucial for developing climate resilient crops in the future.
Here, we review the physiological responses of plants to elevated
CO2, temperature, tropospheric ozone
(O3), and drought conditions, as well as the interaction
of these abiotic stress factors with plant pathogen pressure.
Additionally, we describe the crosstalk and trade-offs involved in plant
responses to both abiotic and biotic stress, and outline targets for
future work to develop a more sustainable future food supply in light of
future climate change.
INTRODUCTION
Anthropogenic increases in fossil fuel emissions have led to atmospheric
concentrations of carbon dioxide (CO2) that are
unprecedented for the last 800,000 years (IPCC, 2021). This has led to
unequivocal warming of the global atmosphere, changes in precipitation
patterns and extreme weather events, and increased sea level rise
leading to coastal flooding (IPCC, 2021). Additionally, other changes in
atmospheric constituents, such as the concentration of secondary air
pollutants like tropospheric ozone (O3), are also
predicted to increase this century (IPCC, 2021). Global climate change
will lead to more frequent and extreme heat waves, drought,
waterlogging, and associated changes in soil moisture (IPCC, 2021).
While the predicted negative impacts of global warming on agricultural
productivity and the associated socioeconomic impact on food systems
have been well reviewed (e.g., Cushman et al., 2022; Fisher et al.,
2005; Hatfield et al., 2011; Vermeulen et al., 2012; Slattery & Ort,
2019), less is known about the significant interactions and trade-offs
between and among different climate change-associated abiotic stresses
on plant productivity (Rivero et al., 2022). For example, while global
warming and associated changes in plant growing conditions have
potential negative impacts on yield and productivity especially for the
latter half of the 21st century (Challinor et al.,
2014; Lobell et al., 2011), elevated CO2 concentrations
[CO2] stimulates growth and harvestable grain
production in C3 crops (Ainsworth et al., 2008). This,
however, comes at a cost of decreased nutritional content in major crop
plants (Myers et al., 2014; Soares et al., 2019), but has also been
shown to be ameliorated under elevated temperature (Kohler et al.,
2019).
Even less is known about these interacting abiotic stress factors in
perennial and specialty cropping systems (Leisner, 2020), and about
crosstalk between abiotic and biotic stress signaling pathways (Fujita
et al., 2006). While there are many unknowns related to the effects of
climate change on pathogen spread, evidence indicates there will be
enhanced reproductive potential and increased geographic spread of
pathogens, which has the potential to lead to changes in disease
dynamics and pathogen host ranges, raising concerns of increased disease
outbreaks (Garret et al., 2006; Kissoudis et al., 2014). Combined biotic
and abiotic stresses can lead to alterations in defense signaling
pathways in plants, predisposing plants to increased susceptibility to
endemic pathogens, but also potentially new pathogens. Here we briefly
review the physiological responses of plants to climate-change related
abiotic stress, outline the complex interplay of stress signaling
pathways between abiotic and biotic stress pathways related to climate
change, and highlight trade-offs and targets for future research efforts
and work to enhance resilience in plant development and defense
responses considering future climate change.
PHYSIOLOGICAL RESPONSES OF PLANTS TO ABIOTIC STRESS