POLA1 and infection: To simulate different levels of infection, we titrated DNA from axenically-grown wheat leaves into DNA from wheat roots that had been cultivated in non-sterile soil and applied hamPCR, using as a host gene RNA polymerase A1 (PolA1), which is present as a single copy in each of the A, B, and D subgenomes (Rai et al., 2012).