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Title: Two Polyketide Synthase-encoding Genes are Required for Biosynthesis of the Polyketide Virulence Factor, T-toxin, by Cochliobolus heterostrophus

Abstract

Cochliobolus heterostrophus race T, causal agent of Southern Corn Leaf Blight, requires T-toxin (a family of C35 – C49 polyketides) for high virulence on T-cytoplasm maize. Production of T-toxin is controlled by two unlinked loci, Tox1A and Tox1B, carried on 1.2 Mb of DNA not found in race O, a mildly virulent form of the fungus that does not produce T-toxin, or in any other Cochliobolus spp. or closely related fungus. PKS1, a polyketide synthase (PKS)-encoding gene at Tox1A and DEC1, a decarboxylase-encoding gene at Tox1B, are necessary for T-toxin production. Although there is evidence that additional genes are required for T-toxin production, efforts to clone them have been frustrated because the genes are located in highly repeated, A+T-rich DNA. To overcome this difficulty, Ligation specificity-based Expression Analysis Display (LEAD), a comparative AFLP/gel fractionation/capillary sequencing procedure was applied to cDNAs from a near isogenic pair of race T (Tox1+) and race O (Tox1-) strains. This led to discovery of PKS2, a second PKS-encoding gene that maps at Tox1A and is required for both T-toxin biosynthesis and high virulence to maize. Thus, the carbon chain of each T-toxin family member is likely assembled by action of two PKSs, which produce twomore » polyketides, one of which may act as the starter unit for biosynthesis of the mature T-toxin molecule.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
883207
Report Number(s):
PNNL-SA-46869
BM0102070
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Molecular Plant-Microbe Interactions, MPMI, 19(2):139-49
Country of Publication:
United States
Language:
English

Citation Formats

Baker, Scott E., Kroken, Scott, Inderbitzin, Patrik, Asvarak, Thipa, Li, Bi-Yu, Shi, Liang, Yoder, Olen C., and Turgeon, Barbara G. Two Polyketide Synthase-encoding Genes are Required for Biosynthesis of the Polyketide Virulence Factor, T-toxin, by Cochliobolus heterostrophus. United States: N. p., 2006. Web. doi:10.1094/MPMI-19-0139.
Baker, Scott E., Kroken, Scott, Inderbitzin, Patrik, Asvarak, Thipa, Li, Bi-Yu, Shi, Liang, Yoder, Olen C., & Turgeon, Barbara G. Two Polyketide Synthase-encoding Genes are Required for Biosynthesis of the Polyketide Virulence Factor, T-toxin, by Cochliobolus heterostrophus. United States. doi:10.1094/MPMI-19-0139.
Baker, Scott E., Kroken, Scott, Inderbitzin, Patrik, Asvarak, Thipa, Li, Bi-Yu, Shi, Liang, Yoder, Olen C., and Turgeon, Barbara G. Wed . "Two Polyketide Synthase-encoding Genes are Required for Biosynthesis of the Polyketide Virulence Factor, T-toxin, by Cochliobolus heterostrophus". United States. doi:10.1094/MPMI-19-0139.
@article{osti_883207,
title = {Two Polyketide Synthase-encoding Genes are Required for Biosynthesis of the Polyketide Virulence Factor, T-toxin, by Cochliobolus heterostrophus},
author = {Baker, Scott E. and Kroken, Scott and Inderbitzin, Patrik and Asvarak, Thipa and Li, Bi-Yu and Shi, Liang and Yoder, Olen C. and Turgeon, Barbara G.},
abstractNote = {Cochliobolus heterostrophus race T, causal agent of Southern Corn Leaf Blight, requires T-toxin (a family of C35 – C49 polyketides) for high virulence on T-cytoplasm maize. Production of T-toxin is controlled by two unlinked loci, Tox1A and Tox1B, carried on 1.2 Mb of DNA not found in race O, a mildly virulent form of the fungus that does not produce T-toxin, or in any other Cochliobolus spp. or closely related fungus. PKS1, a polyketide synthase (PKS)-encoding gene at Tox1A and DEC1, a decarboxylase-encoding gene at Tox1B, are necessary for T-toxin production. Although there is evidence that additional genes are required for T-toxin production, efforts to clone them have been frustrated because the genes are located in highly repeated, A+T-rich DNA. To overcome this difficulty, Ligation specificity-based Expression Analysis Display (LEAD), a comparative AFLP/gel fractionation/capillary sequencing procedure was applied to cDNAs from a near isogenic pair of race T (Tox1+) and race O (Tox1-) strains. This led to discovery of PKS2, a second PKS-encoding gene that maps at Tox1A and is required for both T-toxin biosynthesis and high virulence to maize. Thus, the carbon chain of each T-toxin family member is likely assembled by action of two PKSs, which produce two polyketides, one of which may act as the starter unit for biosynthesis of the mature T-toxin molecule.},
doi = {10.1094/MPMI-19-0139},
journal = {Molecular Plant-Microbe Interactions, MPMI, 19(2):139-49},
number = ,
volume = ,
place = {United States},
year = {Wed Mar 01 00:00:00 EST 2006},
month = {Wed Mar 01 00:00:00 EST 2006}
}
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