Pectin, Lignin and Disease Resistance in Brassica napus L.: An Update

The plant cell wall is dynamically modified during host-pathogen interactions and acts as a crucial factor controlling plant immunity. In the context of recently revised models of plant primary cell walls (PCWs), pectin is considered to be important in determining the mechanical properties of PCWs. A secondary cell wall is present in some cell types and lignin is normally present and acts to strengthen wall rigidity. In this review, we summarize the recent advances in understanding cell-wall-mediated defense responses against pathogens in Brassica napus L. (B. napus). A major part of this response involves pectin and lignin, and these two major cell wall components contribute greatly to immune responses in B. napus. Crosstalk between pectin and lignin metabolism has been detected in B. napus upon pathogen infection, suggesting a synergistic action of pectin and lignin metabolism in regulating cell wall integrity as well as wall-mediated immunity. The transcriptional regulation of cell-wall-mediated immunity in B. napus along with that in Arabidopsis is discussed, and directions for future work are proposed for a better understanding of wall-mediated plant immunity in B. napus.