PDC and infection: SA-mediated PDLP5 activation is required to close PDs by regulating PDC during pathogen infection, and the cals1-1 mutant failed to increase PDC accumulation or change PD permeability when this plant was treated with SA and P. syringae. This result indicates that CalS1 and PDLP5 are strongly associated with PD regulation to control PDC accumulation during SA-mediated immune responses (Figure 1B) [62].