Matthew K Gilbert1, Rajtilak Majumdar2, Kanniah Rajasekaran2, Zhi-Yuan Chen3, Qijian Wei2, Christine M Sickler2, Matthew D Lebar2, Jeffrey W Cary2, Bronwyn R Frame4, Kan Wang4. 1. Food and Feed Safety Unit, Agricultural Research Service, USDA, 100 Robert E Lee Blvd., New Orleans, LA, 70124, USA. matthew.gilbert@ars.usda.gov. 2. Food and Feed Safety Unit, Agricultural Research Service, USDA, 100 Robert E Lee Blvd., New Orleans, LA, 70124, USA. 3. Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, 302 Life Science Building, Baton Rouge, LA, 70803, USA. 4. Plant Transformation Facility, Iowa State University, G405 Agronomy Hall, Ames, IA, 50011, USA.
Abstract
MAIN CONCLUSION: Expressing an RNAi construct in maize kernels that targets the gene for alpha-amylase in Aspergillus flavus resulted in suppression of alpha-amylase (amy1) gene expression and decreased fungal growth during in situ infection resulting in decreased aflatoxin production. Aspergillus flavus is a saprophytic fungus and pathogen to several important food and feed crops, including maize. Once the fungus colonizes lipid-rich seed tissues, it has the potential to produce toxic secondary metabolites, the most dangerous of which is aflatoxin. The pre-harvest control of A. flavus contamination and aflatoxin production is an area of intense research, which includes breeding strategies, biological control, and the use of genetically-modified crops. Host-induced gene silencing, whereby the host crop produces siRNA molecules targeting crucial genes in the invading fungus and targeting the gene for degradation, has shown to be promising in its ability to inhibit fungal growth and decrease aflatoxin contamination. Here, we demonstrate that maize inbred B104 expressing an RNAi construct targeting the A. flavus alpha-amylase gene amy1 effectively reduces amy1 gene expression resulting in decreased fungal colonization and aflatoxin accumulation in kernels. This work contributes to the development of a promising technology for reducing the negative economic and health impacts of A. flavus growth and aflatoxin contamination in food and feed crops.
MAIN CONCLUSION: Expressing an RNAi construct in maize kernels that targets the gene for alpha-amylase in Aspergillus flavus resulted in suppression of alpha-amylase (amy1) gene expression and decreased fungal growth during in situ infection resulting in decreased aflatoxin production. Aspergillus flavus is a saprophytic fungus and pathogen to several important food and feed crops, including maize. Once the fungus colonizes lipid-rich seed tissues, it has the potential to produce toxic secondary metabolites, the most dangerous of which is aflatoxin. The pre-harvest control of A. flavus contamination and aflatoxin production is an area of intense research, which includes breeding strategies, biological control, and the use of genetically-modified crops. Host-induced gene silencing, whereby the host crop produces siRNA molecules targeting crucial genes in the invading fungus and targeting the gene for degradation, has shown to be promising in its ability to inhibit fungal growth and decrease aflatoxin contamination. Here, we demonstrate that maize inbred B104 expressing an RNAi construct targeting the A. flavus alpha-amylase gene amy1 effectively reduces amy1 gene expression resulting in decreased fungal colonization and aflatoxin accumulation in kernels. This work contributes to the development of a promising technology for reducing the negative economic and health impacts of A. flavus growth and aflatoxin contamination in food and feed crops.
Authors: Robert L Brown; Abebe Menkir; Zhi-Yuan Chen; Deepak Bhatnagar; Jiujiang Yu; Haibo Yao; Thomas E Cleveland Journal: Food Addit Contam Part A Chem Anal Control Expo Risk Assess Date: 2013-07-16
Authors: Petr Karlovsky; Michele Suman; Franz Berthiller; Johan De Meester; Gerhard Eisenbrand; Irène Perrin; Isabelle P Oswald; Gerrit Speijers; Alessandro Chiodini; Tobias Recker; Pierre Dussort Journal: Mycotoxin Res Date: 2016-08-23 Impact factor: 3.833