Previous Article | Next Article 
Applied and Environmental Microbiology, March 2007, p. 1622-1629, Vol. 73, No. 5
0099-2240/07/$08.00+0 doi:10.1128/AEM.01077-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.
Reduced Contamination by the Fusarium Mycotoxin Zearalenone in Maize Kernels through Genetic Modification with a Detoxification Gene
Tomoko Igawa ,1,
,
Naoko Takahashi-Ando,1,2,
Noriyuki Ochiai,1
Shuichi Ohsato,1,
Tsutomu Shimizu,3
Toshiaki Kudo,2
Isamu Yamaguchi,1,¶ and
Makoto Kimura1,2*
Plant & Microbial Metabolic Engineering Research Unit and Laboratory for Remediation Research, Discovery Research Institute (DRI) and Plant Science Center (PSC1), RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan,1 Environmental Molecular Biology Laboratory, Discovery Research Institute (DRI), RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan,2 Life Science Research Institute, Kumiai Chemical Industry Co., Ltd., Tamari 276, Kakegawa, Shizuoka 436-0011, Japan3
Received 10 May 2006/ Accepted 20 December 2006
Maize is subject to ear rot caused by toxigenic Aspergillus and Fusarium species, resulting in contamination with aflatoxins, fumonisins, trichothecenes, and zearalenone (ZEN). The trichothecene group and ZEN mycotoxins are produced by the cereal pathogen Fusarium graminearum. A transgenic detoxification system for the elimination of ZEN was previously developed using an egfp::zhd101 gene (gfzhd101), encoding an enhanced green fluorescent protein fused to a ZEN-degrading enzyme. In this study, we produced a transgenic maize line expressing an intact copy of gfzhd101 and examined the feasibility of transgene-mediated detoxification in the kernels. ZEN-degrading activity has been detected in transgenic kernels during seed maturation (for a period of 6 weeks after pollination). The level of detoxification activity was unaltered after an additional storage period of 16 weeks at 6°C. When the seeds were artificially contaminated by immersion in a ZEN solution for 48 h at 28°C, the total amount of the mycotoxin in the transgenic seeds was uniformly reduced to less than 1/10 of that in the wild type. The ZEN in the transgenic maize kernels was also efficiently decontaminated under conditions of lower water activity (aw) and temperature; e.g., 16.9 µg of ZEN was removed per gram of seed within 48 h at an aw of 0.90 at 20°C. F. graminearum infection assays demonstrated an absence of ZEN in the transgenic maize seeds, while the mycotoxin accumulated in wild-type kernels under the same conditions. Transgene-mediated detoxification may offer simple solutions to the problems of mycotoxin contamination in maize.
* Corresponding author. Mailing address: Plant & Microbial Metabolic Engineering Research Unit, Discovery Research Institute (DRI), RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan. Phone: 81-48-467-9796. Fax: 81-48-462-4394. E-mail: mkimura{at}riken.jp.
Published ahead of print on 5 January 2007.
T. Igawa and N. Takahashi-Ando should be considered as joint first authors.
Present address: Plant Protein Biology, Department of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma-shi, Nara 630-0101, Japan.
Present address: Shibata Distinguished Senior Scientist Laboratory, Discovery Research Institute (DRI), RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
¶ Present address: Presidential Office, Agricultural Chemicals Inspection Station (ACIS), 2-772 Suzuki-cho, Kodaira, Tokyo 187-0011, Japan.
Applied and Environmental Microbiology, March 2007, p. 1622-1629, Vol. 73, No. 5
0099-2240/07/$08.00+0 doi:10.1128/AEM.01077-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»