title: Growth inhibition of a Fusarium verticillioides GUS strain in corn kernels of aflatoxin-resistant genotypes.
abstract: Two corn genotypes, GT-MAS:gk and MI82, resistant to Aspergillus flavus infection/aflatoxin contamination, were tested for their ability to limit growth of Fusarium verticillioides. An F. verticillioides strain was transformed with a beta-glucuronidase (GUS) reporter gene (uidA) construct to facilitate fungal growth quantification and then inoculated onto endosperm-wounded and non-wounded kernels of the above-corn lines. To serve as a control, an A. flavus strain containing the same reporter gene construct was inoculated onto non-wounded kernels of GT-MAS:gk. Results showed that, as in a previous study, non-wounded GT-MAS:gk kernels supported less growth (six- to ten-fold) of A. flavus than did kernels of a susceptible control. Also, non-wounded kernels of GT-MAS:gk and M182 supported less growth (two- to four-fold) of F. verticillioides than did susceptible kernels. Wounding, however, increased F. verticillioides infection of MI82, but not that of GT-MAS:gk. This is in contrast to a previous study of A. flavus, where wounding increased infection of GT-MAS:gk rather than M182 kernels. Further study is needed to explain genotypic variation in the kernel response to A. flavus and F. verticillioides kernel infections. Also, the potential for aflatoxin-resistant corn lines to likewise inhibit growth of F. verticillioides needs to be confirmed in the field.
authors.affiliation: Southern Regional Research Center, US Department of Agriculture, Agricultural Research Service, New Orleans, LA 70179, USA. rbrown@srrc.ars.usda.gov
authors.forename: R L
authors.initials: RL
authors.lastname: Brown
authors.forename: T E
authors.initials: TE
authors.lastname: Cleveland
authors.forename: C P
authors.initials: CP
authors.lastname: Woloshuk
authors.forename: G A
authors.initials: GA
authors.lastname: Payne
authors.forename: D
authors.initials: D
authors.lastname: Bhatnagar
mesh_terms: D000348:Aflatoxins / Q000633:toxicity; D000935:Antifungal Agents / Q000378:metabolism; D004351:Drug Resistance / Q000235:genetics; D005670:Fusarium / Q000254:growth & development* / Q000472:pathogenicity*; D017930:Genes, Reporter; D005838:Genotype; D005966:Glucuronidase / Q000235:genetics; D014361:Trypsin Inhibitors / Q000378:metabolism; D003313:Zea mays / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology*
chemical_list: D000348:Aflatoxins; D000935:Antifungal Agents; D014361:Trypsin Inhibitors; D005966:Glucuronidase