Figure 2.

Responses of host plants and pathogens to external and internal hypoxia. (A) In planta responses during infection under external normoxia. (B) Effect of external hypoxia on in planta responses during infection. External hypoxia induces host susceptibility by regulating defense responses and affecting tissue functions. (C) Effect of internal hypoxia on host plants and pathogens. The pathogen infection leads to internal hypoxia in host plant, and hypoxic environment affects both the host and the pathogen. PAL, phenylalanine ammonia-lyase; PER, peroxidase; 4-CL, 4-coumerate coenzyme A ligase; CAD, cinnamyl alcohol dehydrogenase; ROS, reactive oxygen species; HCD, hypersensitive cell death; PDC, pyruvate decarboxylase; ADH, alcohol dehydrogenase.