Pathotoxin effects in sorghum are also produced by mercuric chloride treatment.

Pathogenic isolates of Periconia circinata produce a host-specific toxin (PC-toxin) and cause a root and crown rot in susceptible genotypes of sorghum. Treatment with PC-toxin leads to selective development of disease symptoms and an increase in synthesis of a group of acidic, low molecular weight proteins only in susceptible genotypes. Treatment of sorghum seedlings or excised root tips with HgCl(2) resulted in responses indistinguishable from those produced by treatment with PC-toxin, but the effects were not genotype specific.