How do plants cope with combined stressors?

In the field, heat often arrives with drought, flooding with disease, and pollution on top of both. Plants respond to such combinations in ways that cannot be predicted from each stress alone, so crops bred to tolerate one stress may fail when several strike together.

Question

How do plants cope with combined stressors, meaning two or more abiotic or biotic stresses (heat, drought, salinity, flooding, nutrient deficiency, pollutants, pathogens, pests) acting at the same time or in sequence? The question asks which responses are specific to combinations, what limits tolerance, and how to breed or engineer crops that tolerate the combinations expected as the climate changes.

Background

This is one of eleven exemplar questions in the 2023 list of 100 important questions facing plant science, chosen by the panels to represent plant stress responses, one of the areas with the most submissions [1]. The authors note that it overlaps a question already on the original 2011 list, a sign of how long important topics take to resolve [1]. Climate change is expected to make stress combinations more frequent, with direct consequences for yields.

What is known

Farmers and breeders have long known that simultaneous stresses are often the most damaging to crops, and plant responses to a combination of two abiotic stresses are unique: they cannot be extrapolated from the responses to each stress applied alone [2].
When Arabidopsis seedlings were exposed to six stresses together, each at a level with negligible effect on its own, the combined impact on growth and survival was severe, and specific pathways were needed for acclimation [3].
Five low-level stresses combined (salinity, heat, the herbicide paraquat, phosphorus deficiency and cadmium) significantly reduced the growth and biomass of a commercial rice cultivar and a maize hybrid, and 42 rice genotypes differed substantially in their response [4].
A review argues that strategies that improve tolerance to one stress may fail when that stress is combined with others, and proposes approaches for breeding crops resilient to stress combinations [5].

What would count as progress

No single result settles a question like this; contributions like these would move it forward:

Open phenotyping datasets of diverse crop genotypes under factorial combinations of stresses, in controlled environments and in the field, including yield.
Genetic loci or markers for tolerance to specific combinations, validated in independent populations and seasons.
Crop models that represent interactions between stresses and predict yield losses in observed compound events, such as hot and dry seasons, better than single-stress models.

References

Armstrong, E. M. et al. (2023). One hundred important questions facing plant science: an international perspective. New Phytologist 238(2), 470–481.
Mittler, R. (2006). Abiotic stress, the field environment and stress combination. Trends in Plant Science 11(1), 15–19.
Zandalinas, S. I. et al. (2021). The impact of multifactorial stress combination on plant growth and survival. New Phytologist 230(3), 1034–1048.
Sinha, R. et al. (2024). The effects of multifactorial stress combination on rice and maize. Plant Physiology 194(3), 1358–1369.
Rivero, R. M., Mittler, R., Blumwald, E. & Zandalinas, S. I. (2022). Developing climate-resilient crops: improving plant tolerance to stress combination. The Plant Journal 109(2), 373–389.

Source

Imported from One hundred important questions facing plant science, question 10, curated by Armstrong et al. Listed as open in the source (2023) and still an active research question as of 2026-10-20. The statement above is written in our own words; see the source for the original wording, history and discussion.