The Ecology of Salicylic Acid Signaling: Primary, Secondary and Tertiary Effects with Applications in Agriculture

Abstract

The salicylic acid pathway is one of the primary plant defense pathways, is ubiquitous in vascular plants, and plays a role in rapid adaptions to dynamic abiotic and biotic stress. Its prominence and ubiquity make it uniquely suited for understanding how biochemistry within plants can mediate ecological consequences. Induction of the salicylic acid pathway has primary effects on the plant in which it is induced resulting in genetic, metabolomic, and physiologic changes as the plant adapts to challenges. These primary effects can in turn have secondary consequences for herbivores and pathogens attacking the plant. These secondary effects can both directly influence plant attackers and mediate indirect interactions between herbivores and pathogens. Additionally, stimulation of salicylic acid related defenses can affect natural enemies, predators and parasitoids, which can recruit to plant signals with consequences for herbivore populations and plant herbivory aboveground and belowground. These primary, secondary, and tertiary ecological consequences of salicylic acid signaling hold great promise for application in agricultural systems in developing sustainable high-yielding management practices that adapt to changing abiotic and biotic environments.

Salicylic Acid Signalling in Plants

“…This is also indicated by the fact that a relatively new approach, the involvement of SA in endoplasmic reticulum stress, has also been reviewed [3]. Finally, the last review addresses a possible practical use of SA, and its ecological consequences are also discussed [4].…”

“…The compounds' effects must be known both for the plants where they are used, and for the wider environment. A recent review by Filgueiras and co-workers provides a detailed overview about the induction pathways induced by SA at the primary (genetic, metabolomic, and physiologic changes in plants), secondary (effects on herbivores and pathogens attacking the plants), and tertiary levels (with consequences for herbivore populations) [4]. For example, in addition to the investigation of the primary molecular effects of SA, another potential approach for the control of herbivores in agricultural systems through defences related to SA is attraction of natural enemies of the insects.…”

A multi-omics approach to solving problems in plant disease ecology

“…Nowhere is this as apparent as with the role of the salicylic acid (SA) signaling pathway. While there are many important plant defence pathways involving other critical plant hormones such as abscisic acid and jasmonic acid, for example, the SA pathway plays a critical role in regulating plant disease ecology with regulation of plant systemic acquired resistance and mediation of the interactions between members of plant microbial communities [120].…”

“…The SA signaling pathway and systemic acquired resistance not only affects the plant pathogen microbial community, but also a whole host of other organisms [120]. To do so, mobile volatile signals are used such as the methylated form of SA, methyl salicylate (MeSA) [146].…”

“…To do so, mobile volatile signals are used such as the methylated form of SA, methyl salicylate (MeSA) [ 146 ]. Volatilomics approaches to SA signaling have revealed that volatile profiles of plants change upon induction of the SA defense pathway [ 120 ]. These changes in volatile profiles can result in the induction of SA responses in neighboring plants and recruitment of natural enemies aboveground and belowground in the rhizosphere [ 147 – 150 ].…”