CA8 and infection: CalS, or callose synthase, corresponds to a class of enzymes involved in callose biosynthesis in plants (Chen and Kim, 2009), a minor component of healthy plant tissue which rapidly accumulates around the infection site in order to reinforce cell walls and prevent fungal invasion (Vidhyasekaran, 2007; Hückelhoven, 2014; Kuhn et al., 2016).