The Influence of Light on Bryophytes and Their Response to Pathogen Infection: A Story of Mnium cuspidatum and Physcomitrella patens

The influence of light on non-vascular plant-pathogen interactions were studied in two moss species, Mnium cuspidatum and Physcomitrella patens, using a fungal pathogen, Pythium irregulare, and a commonly used pathogenic elicitor (beta-glucan). The findings of this study suggest that light does playa role in moss defense but speci fic mechanisms remain unclear. In P. patens it was found that the defense gene AOe was up-regulated in the light compared to the dark when treated with beta-glucan elicitor. A phenotypic study of M. cuspidatum revealed that P. irregulare will infect and M cuspidatum will subsequently mount a defense response. Unexpectedly, samples of M. cuspidatum appeared healthier in the dark compared to the light when inoculated with P. irregulare. Systemic acquired resistance (SAR) was also observed in M. cuspidatum and three related genes, PAL, PR-4, and PR-S were identified in the genome