Publication: Six new genes required for production of T-toxin, a polyketide determinant of high virulence of Cochliobolus heterostrophus to maize
Issued Date
2010-04-01
Resource Type
ISSN
08940282
Other identifier(s)
2-s2.0-77949277551
Rights
Mahidol University
Rights Holder(s)
SCOPUS
Bibliographic Citation
Molecular Plant-Microbe Interactions. Vol.23, No.4 (2010), 458-472
Suggested Citation
Patrik Inderbitzin, Thipa Asvarak, B. Gillian Turgeon Six new genes required for production of T-toxin, a polyketide determinant of high virulence of Cochliobolus heterostrophus to maize. Molecular Plant-Microbe Interactions. Vol.23, No.4 (2010), 458-472. doi:10.1094/MPMI-23-4-0458 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/28518
Research Projects
Organizational Units
Authors
Journal Issue
Thesis
Title
Six new genes required for production of T-toxin, a polyketide determinant of high virulence of Cochliobolus heterostrophus to maize
Other Contributor(s)
Abstract
Southern Corn Leaf Blight, one of the worst plant disease epidemics in modern history, was caused by Cochliobolus heterostrophus race T, which produces T-toxin, a determinant of high virulence to maize carrying Texas male sterile cytoplasm. The genetics of T-toxin production is complex and the evolutionary origin of associated genes is uncertain. It is known that ability to produce T-toxin requires three genes encoded at two unlinked loci, Tox1A and Tox1B, which map to the breakpoints of a reciprocal translocation. DNA associated with Tox1A and Tox1B sums to about 1.2 Mb of A+T rich, repeated DNA that is not found in less virulent race O or other Cochliobolus species. Here, we describe identification and targeted deletion of six additional genes, three mapping to Tox1A and three to Tox1B. Mutant screens indicate that all six genes are involved in Ttoxin production and high virulence to maize. The nine known Toxi genes encode two polyketide synthases (PKS), one decarboxylase, five dehydrogenases, and one unknown protein. Only two have a similar phylogenetic profile. To trace evolutionary history of one of the core PKS, DNA from more than 100 Dothideomycete species were screened for homologs. An ortholog (60% identity) was confirmed in Didymella zeae-maydis, which produces PM-toxin, a polyketide of similar structure and biological specificity as Ttoxin. Only one additional Dothideomycete species, the dung ascomycete Delitschia wintert harbored a paralog. The unresolved evolutionary history and distinctive gene signature of the PKS (fast-evolving, discontinuous taxonomic distribution) leaves open the question of lateral or vertical transmission. © 2010 The American Phytopathological Society.