Plant diseases have devastating consequences on crops, causing losses of up to 30% in crop production. Fortunately, plants have developed a robust immune system that allows them to defend themselves. An important component of this immune system that has attracted the attention of numerous researchers in recent years is the plant cell wall.
Plant cell wall is a complex cell structure that surrounds all plant cells. This structure plays a very important role as a physical barrier that pathogens must overcome to colonize the plant tissue and cause diseases. In addition, cell wall is also a dynamic structure that is modified during the infection process or in response to environmental stresses, altering its structural integrity. These changes in the integrity of the cell wall cause the release of molecules (called DAMPs, fromDamage Associated Molecular Patterns) that are perceived by receptors of the plant immune system triggering disease resistance responses.
Researchers at the Centre for Plant Biotechnology and Genomics (CBGP) have recently described in the journal "Frontiers in Plant Science" a novel group of cell wall-derived DAMPs. In a previous work recently published, Dr. Antonio Molina's group showed that cell wall fractions extracted from the cell wall mutant impaired in Arabidopsis Response Regulator 6 (arr6), that showed altered disease resistance to several pathogens, triggered more intense immune responses than those activated by similar cell wall fractions from wild-type plants. In this work, researchers have described the characterization of the previous immune-active fractions of arr6 showing the highest triggering capacities upon further fractionation by chromatographic means. The analyses pointed for the first time to a role of pentose-based oligosaccharides triggering plant immune responses. The characterization of several pentose-based oligosaccharide structures revealed that β-1,4-xylooligosaccharides of specific degrees of polymerization and carrying arabinose decorations are sensed as DAMPs by plants. Interestingly, these molecules enhanced plant defense capacities when applied to crops and improve crops disease resistance to pathogenic fungi and bacteria. The data showed in this article pointed to an interesting interaction between wall composition, innate immunity signaling and disease resistance. In the future, the use of formulations based on similar molecules could represent a simple, sustainable and effective treatment to avoid crop losses caused by some diseases. This DAMP-based crop protection technology with natural products extracted from plant biomass (cell wall) will contribute to a more sustainable agriculture and to the circular bioeconomy.
Mélida, H., Bacete, L., Ruprecht, C., Rebaque, D., del Hierro, I., López, G., Brunner, F., Pfrengle, F., Molina, A. 2020. Arabinoxylan-Oligosaccharides Act as Damage Associated Molecular Patterns in Plants Regulating Disease Resistance. Frontiers in Plant Science 11, 1210. DOI: 10.3389/fpls.2020.01210