Home • Didymella zeae-maydis 3018
Photo of Didymella zeae-maydis 3018
Maize leaves inoculated with Didymella zeae-maydis. Arrows point to chlorotic regions caused by PM-toxin which accompany necrotic lesions.
Image Credit: B. Gillian Turgeon

The dothideomycete Didymella zeae-maydis, the causal agent of Yellow Leaf Blight of maize, was first observed in Ohio in 1965 [1] then soon after in most corn growing states of the US and Canada.  The fungus was initially described as Phyllosticta zeae [2, 3], then Phyllosticta maydis [4]. When the teleomorph was discovered in 1973, it was renamed Mycosphaerella zeae-maydis [5], then Didymella zeae-maydis [6].  The name Peyronellaea zeae-maydis is suggested by authors of a recent publication [7] reporting multilocus sequence typing.
From the beginning, it was clear that only Texas male sterile cytoplasm (Tcms) was highly susceptible to attack by D. zeae-maydis.  Moreover in 1973, a polyketide secondary metabolite, PM-toxin [8], with toxicity only to Tcms was identified.  Tcms carries the Urf13 protein target of the toxin in the inner mitochondrial membrane.  PM-toxin has exactly the same biological specificity as the polyketide secondary metabolite, T-toxin, produced by Cochliobolus heterostrophus race T causal agent of the 1970 Southern Corn Leaf Blight epidemic.  Race T was unknown until the time of the epidemic, although race O, which does not produce T-toxin was discovered decades earlier.   Both T-toxin and PM-toxin are families of linear polyketides, however PM-toxin, as a family, consists of shorter carbon chain backbones (C33 to C35) than the T-toxin family (C35 to C41). In contrast to C. heterostrophus with two known races, no toxin-minus isolate of D. zeae-maydis is known.  The history of evolution of genes conferring toxin-producing activity is under investigation.
D. zeae-maydis is genetically tractable and there are established protocols for transformation, gene disruption and targeted gene manipulation [9].  The fungus is homothallic [10].
D. zeae-maydis strain 3018 was sequenced using an Illumina HiSeq 2000-based whole-genome shotgun strategy (S-H Yun, Dept. of Medical Biotechnology, Soonchunhyang University, Asan, South Korea).

This research was supported by a grant from the Next-Generation Bio Green21 Program (no. PJ0111802015), the Rural Development Administration, Republic of Korea.



  1.   McFeeley, J.C., Comparison of isolates causing Yellow Leaf Blight of corn in Ohio. Plant Dis. Reptr., 1971. 55: p. 1064-1068.
  2. Scheifele, G.L. and R.R. Nelson, The occurrence of Phyllosticta leaf spot of corn in Pennsylvania. Plant Dis. Reptr., 1969. 53: p. 186-189.
  3. Scheifele, G.L., R.R. Nelson , and C. Koons, Male sterility cytoplasm conditioning susceptibility of resistant inbred lines of maize to Yellow Leaf Blight caused by Phyllosticta zeae. Plant Dis. Reptr., 1969. 53: p. 656-659.
  4. Arny, D.C. and R.R. Nelson, Phyllosticta maydis species nova, the incitant of Yellow Leaf Blight of maize. Phytopathology, 1971. 61: p. 1170-1172.
  5. Mukunya, D.M. and C.W. Boothroyd, Mycosphaerella zeae-maydis sp. n., the sexual stage of Phyllosticta maydis. Phytopathology, 1973. 63: p. 529-532.
  6. Arx, J., von, Plant pathogenic fungi. Beihefte zur Nova Hedwigia 1987. 87: p. 288.
  7. Aveskamp, M.M., J. de Gruyter, J.H.C. Woudenberg, G.J.M. Verkley, and P.W. Crous, Highlights of the Didymellaceae: A polyphasic approach to characterise Phoma and related pleosporalean genera. Studeis in Mycology, 2010. 65 p. 1–60.
  8. Yoder, O.C., A selective toxin produced by Phyllosticta maydis. Phytopathology, 1973. 63: p. 1361-1365.
  9. Yun, S.H., B.G. Turgeon, and O.C. Yoder, REMI-induced mutants of Mycosphaerella zeae-maydis lacking the polyketide PM-toxin are deficient in pathogenesis to corn. Physiol. Mol. Plant Pathol., 1998. 52(1): p. 53-66.
  10. Yun, S.H., O.C. Yoder, and B.G. Turgeon, Structure and function of the mating-type locus in the homothallic ascomycete, Didymella zeae-maydis. J Microbiol, 2013. 51(6): p. 814-20.


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