To further investigate the hypothesis that pathogens require the initial light cycle to enter through the stomata following the first phase of the infection process, we utilized the developed methodology to visualize the effects of extended initial periods of darkness after Pgt inoculation using the two Pgt races, QCCJB and HKHJC, inoculated on resistant and susceptible barley genotypes and a susceptible wheat line. The gene discussed is SLCO2A1; the disease is infection.