RETNLB and neoplasm: The effector Pit2 inhibits the activity of the key virulence target maize cysteine protease (CP1A, CP1B, CP2, and XCP2), which is required for the formation of tumours, while mutant pit2 strains induce a strong defence response in the host, suppressing mycelial spread and tumour formation (Doehlemann et al., 2011; Mueller et al., 2013).