Synthetic plant defense elicitors

Abstract

o defend themselves against invading pathogens plants utilize a complex regulatorynetwork that coordinates extensive transcriptional and metabolic reprogramming. Althoughmany of the key players of this immunity-associated network are known, the detailsof its topology and dynamics are still poorly understood. As an alternative to forwardand reverse genetic studies, chemical genetics-related approaches based on bioactivesmall molecules have gained substantial popularity in the analysis of biological pathwaysand networks. Use of such molecular probes can allow researchers to access biologicalspace that was previously inaccessible to genetic analyses due to gene redundancy orlethality of mutations. Synthetic elicitors are small drug-like molecules that induce plantdefense responses, but are distinct from known natural elicitors of plant immunity. Whilethe discovery of some synthetic elicitors had already been reported in the 1970s,recent breakthroughs in combinatorial chemical synthesis now allow for inexpensivehigh-throughput screens for bioactive plant defense-inducing compounds. Along withpowerful reverse genetics tools and resources available for model plants and crop systems,comprehensive collections of new synthetic elicitors will likely allow plant scientists tostudy the intricacies of plant defense signaling pathways and networks in an unparalleledfashion. As synthetic elicitors can protect crops from diseases, without the need to bedirectly toxic for pathogenic organisms, they may also serve as promising alternatives toconventional biocidal pesticides, which often are harmful for the environment, farmers andconsumers. Here we are discussing various types of synthetic elicitors that have been usedfor studies on the plant immune system, their modes-of-action as well as their applicationin crop protection.