Agar plates with a 180-colony grid were used for cell growth and kept in low light (50 lmol photons m2
/s).
Fungal contamination was controlled by supplementing plates with carbendazim (70 lg/ml). A total of 135 agar
plates were generated and replica-plated monthly. For DNA preparation, all 180 colonies from one plate were
combined and the DNA was extracted (Supplemental Materials). DNA preparations from five such plates were
further combined (referred to as ‘‘pooled DNA’’ in the text) to allow for the simultaneous screening of 900 individual
colonies in a PCR screen. Thus, DNA from 135 plates was used to produce 27 DNA pools for the PCR screen.