Laminarin-triggered defence responses are geographically dependent for natural populations ofSolanum chilense

Abstract

Natural plant populations are highly polymorphic and often show intraspecific quantitative, variation in resistance properties against pathogens. The activation of the underlying defence responses can depend on the perception of conserved pathogen-associated molecular patterns (PAMPs). To dissect and understand such variation, we evaluated the diversity of responses induced by laminarin (representing a general glucan elicitor of plant immune responses) in the wild tomato species Solanum chilense. We confirm considerable overlap of the plant's global transcriptional responses to laminarin and to the oomycete pathogen Phytophthora infestans. We further measured key components of basal defence responses such as reactive oxygen species (ROS) production and levels of diverse phytohormones and their derivatives upon elicitation with laminarin in 83 plants originating from nine natural populations of S. chilense from distinct geographic origin. We found high diversity in these components at basal and elicitor-induced levels. We generated generalised linear mixed models (GLMMs) with these components to explain the observed resistance phenotype against P. infestans in the plants and found that additive effects of multiple components best explain resistance at the species level. For individual components, we observed the strongest positive correlation between the resistance phenotype and ethylene (ET) production upon laminarin elicitation. The strength of this correlation differed between individual populations. Chemical inhibition of ET production in individuals from a population, in which ET production was associated with resistance, provoked more severe disease symptoms. Our findings reveal high diversity in the strength of induced defence responses within a species and in the basal levels of other stress-related phytohormones. We show the involvement of multiple components with a quantitatively different contribution of individual components to resistance in geographically separated populations of S. chilense against P. infestans.

Chemiluminescence‐Based Assay to Monitor Early Oxidative Bursts in Soybean (Glycine max) Lateral Roots

“…These findings highlight the differential abilities of the elicitors to induce ROS production in soybean root tissues. A recent study showed intraspecific diversity in initial immune responses toward glucans in the wild tomato species using the ROS burst assay (Kahlon et al., 2021, 2023). To investigate and comprehend such variation in soybean cultivars’ chitin perception, we conducted the ROS burst assay in the root tissues of three soybean cultivars (JS‐2029, JS‐2034, and JS‐2098) using Chit 6 at a concentration of 25 µM (Fig.…”

Small‐spored Alternaria spp. (section Alternaria) are common pathogens on wild tomato species

“…Passalora fulva; Stam et al, 2017Stam et al, , 2019Kahlon et al, 2020). Additionally, significant genetic diversity exists among resistance genes (Kahlon et al, 2020;Stam et al, 2019) and populations show clear variation in quantitative defence responses within and between populations (Kahlon et al, 2021). Specific horizontal or vertical resistance properties against a range of pathogens have been identified in other tomato spp.…”

Small-sporedAlternariaspp. (sectionAlternaria) are common pathogens on wild tomato species

“…Passalora fulva) (Stam et al ., 2017, 2019; Kahlon et al ., 2020). Additionally, significant genetic diversity exists among resistance genes (Stam et al ., 2019; Kahlon et al ., 2020) and populations show clear variation in quantitative defense responses within an between populations (Kahlon et al ., 2021). Specific horizontal or vertical resistance properties against a range of pathogens have been identified in other tomato spp.…”