The cell walls of plants are like a fortress, fiercely guarding against invading fungal pathogens. But, in order to fend off these invaders, the plant must fortify its walls to withstand the physical and chemical attacks of the fungus. The papillae, tiny protuberances on the cell walls, have been known to be particularly effective in warding off these pathogens, and have long been thought to contain callose as their main component. However, in a recent study, we delved deeper into the composition of barley papillae under attack from powdery mildew fungus, using advanced tools and techniques.

To our surprise, we discovered that these papillae also contained significant concentrations of cellulose and arabinoxylan, in addition to callose. And, the more effective papillae had even higher concentrations of these polysaccharides. The papillae were also found to have a layered structure, with the inner core made of callose and arabinoxylan, and the outer layer containing arabinoxylan and cellulose.

This discovery opens up new avenues for improving the composition of papillae to enhance disease resistance in plants. 

Author: Jamil Chowdhury

20 August 2014.