Hitting the Wall: Plant Cell Walls During Botrytis cinerea Infections

Abstract

The cell wall is among the first structures that Botrytis cinerea encounters when colonizing plant tissues. From the perspective of B. cinerea as an infecting pathogen, host cell walls are potential sources of nutrients, but intact walls are also barriers that limit advancement of growing fungal hyphae beyond the initial sites of penetration. Plant cell walls are polysaccharide-rich extracellular matrices that surround individual cells. The architecture and composition of cell walls vary among plant species and organs. The shapes and attributes of organs are determined by the arrangements of the macromolecules that compose cell walls. Walls are synthesized, remodeled and disassembled as cells divide, differentiate, expand, and expire. Metabolic, developmental and external events, including infections by pathogens, alter the properties and components of plant cell walls. This chapter focuses on the cell walls of host plant tissues during infections by B. cinerea. The expression and the polysaccharide targets of B. cinerea and plant genes predicted to encode proteins that could modify plant cell walls as a consequence of infection are described. The impacts of these proteins on the properties of walls are discussed, noting potential alterations to extracellular anti-pathogen and pathogen-related defence proteins associated with the wall matrix.