Elevated Temperature Differentially Influences Effector-Triggered Immunity Outputs in Arabidopsis

Abstract

Pseudomonas syringae is a Gram-negative bacterium that infects multiple plant species by manipulating cellular processes via injection of type three secreted effectors (T3SEs) into host cells. Nucleotide-binding leucine-rich repeat (NLR) resistance (R) proteins recognize specific T3SEs and trigger a robust immune response, called effector-triggered immunity (ETI), which limits pathogen proliferation and is often associated with localized programmed cell death, known as the hypersensitive response (HR). In this study, we examine the influence of elevated temperature on two ETI outputs: HR and pathogen virulence suppression. We found that in the Arabidopsis thaliana accession Col-0, elevated temperatures suppress the HR, but have minimal influence on ETI-associated P. syringae virulence suppression, thereby uncoupling these two ETI responses. We also identify accessions of Arabidopsis that exhibit impaired P. syringae virulence suppression at elevated temperature, highlighting the natural variation that exists in coping with biotic and abiotic stresses. These results not only reinforce the influence of abiotic factors on plant immunity but also emphasize the importance of carefully documented environmental conditions in studies of plant immunity.

Evidence for intragenic recombination and selective sweep in an effector gene of Phytophthora infestans

“…In addition, environmental factors such as temperature may interact with host resistance influencing the fitness of Avr3a in P. infestans . Temperature is one of the most important environmental parameters crucially impacting many aspects of host–pathogen interactions including host susceptibility (Menna, Nguyen, Guttman, & Desveaux, 2015), pathogen density (Mikkelsen, Jørgensen, & Lyngkjær, 2015), and effector gene expression (Banta et al., 1998). The hypothesis of temperature‐mediated Avr3a fitness is supported by significant associations of isoform frequency with the mean annual temperature in the sample sites (Figure 4).…”

The plant hypersensitive response: concepts, control and consequences

“…• Menna et al (2015) reported that elevated temperature altered resistance and HR in quantitatively different and genotype-dependent ways. • The TIR-NBS-LRR protein RPS6 confers resistance to P. syringae without visible cell death (Gassmann, 2005;Kim et al, 2009).…”

Plant immunity in signal integration between biotic and abiotic stress responses

“…ETI suppression at high temperatures seems to be a genetically underpinned and adaptive trait, given the natural variations in A. thaliana for the temperature sensitivity of ETI (Menna et al ., ). Temperature‐sensitive components include NLR proteins themselves: NLR accumulation or nuclear localization is often reduced at high temperatures (Alcázar & Parker, ).…”