ToxA is produced by particular Pyrenophora tritici-repentis races and is a proteinaceous host-selective toxin. It is necessary and sufficient to cause cell death in sensitive wheat cultivars [1].ToxA adopts a single-domain, beta-sandwich fold which has novel topology. The protein is directly involved in recognition events required for ToxA action. It is thought to be distantly related to FnIII proteins, gaining entry to the host via an integrin-like receptor [1].

1: Structure of Ptr ToxA: an RGD-containing host-selective toxin from Pyrenophora tritici-repentis. Sarma GN, Manning VA, Ciuffetti LM, Karplus PA; Plant Cell. 2005;17:3190-3202. PMID:16214901