Seeing Polycentrically: Examining Governance Situations Using a Polycentricity Lens

Because many types of governance can be polycentric, an observer faces a challenge in trying to identify and understand polycentric governance in actual settings. This chapter adopts the perspective of thinking about polycentricity as a lens through which to view governance situations. We take an inquiry approach, considering how one might determine whether and in what ways a given governance situation demonstrates the characteristics of polycentric governance. We proceed through a series of questions an observer could pose as part of 'seeing polycentrically', i.e., looking at the aspects and dimensions of polycentric governance introduced in Stephan, Marshall, and McGinnis as a way of building an understanding of a governance situation. We attempt to describe why these queries are important and how posing and answering these questions helps in examining and understanding the situation. We close the chapter by considering the challenges of assessing the operation of polycentric governance arrangements

Host-induced bacterial cell wall decomposition mediates pattern-triggered immunity in Arabidopsis

Peptidoglycans (PGNs) are immunogenic bacterial surface patterns that trigger immune activation in metazoans and plants. It is generally unknown how complex bacterial structures such as PGNs are perceived by plant pattern recognition receptors (PRRs) and whether host hydrolytic activities facilitate decomposition of bacterial matrices and generation of soluble PRR ligands. Here we show that Arabidopsis thaliana, upon bacterial infection or exposure to microbial patterns, produces a metazoan lysozyme-like hydrolase (lysozyme 1, LYS1). LYS1 activity releases soluble PGN fragments from insoluble bacterial cell walls and cleavage products are able to trigger responses typically associated with plant immunity. Importantly, LYS1 mutant genotypes exhibit super-susceptibility to bacterial infections similar to that observed on PGN receptor mutants. We propose that plants employ hydrolytic activities for the decomposition of complex bacterial structures, and that soluble pattern generation might aid PRR-mediated immune activation in cell layers adjacent to infection sites. DOI: http://dx.doi.org/10.7554/eLife.01990.00