Resistance to Aflatoxin Accumulation in Maize Mediated by Host-Induced Silencing of the <i>Aspergillus flavus</i> Alkaline Protease (<i>alk</i>) Gene
<i>Aspergillus flavus</i> is a fungal pathogen that infects maize and produces aflatoxins. Host-Induced Gene Silencing (HIGS) has been shown to reduce host infection by various fungal pathogens. Here, the <i>A. flavus</i> alkaline protease (<i>alk</i>) gene was ta...
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MDPI AG
2021-10-01
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| Series: | Journal of Fungi |
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| author | Olanike Omolehin Yenjit Raruang Dongfang Hu Zhu-Qiang Han Qijian Wei Kan Wang Kanniah Rajasekaran Jeffrey W. Cary Zhi-Yuan Chen |
| author_facet | Olanike Omolehin Yenjit Raruang Dongfang Hu Zhu-Qiang Han Qijian Wei Kan Wang Kanniah Rajasekaran Jeffrey W. Cary Zhi-Yuan Chen |
| author_sort | Olanike Omolehin |
| collection | DOAJ |
| description | <i>Aspergillus flavus</i> is a fungal pathogen that infects maize and produces aflatoxins. Host-Induced Gene Silencing (HIGS) has been shown to reduce host infection by various fungal pathogens. Here, the <i>A. flavus</i> alkaline protease (<i>alk</i>) gene was targeted for silencing through HIGS. An RNAi vector carrying a portion of the <i>alk</i> gene was incorporated into the B104 maize genome. Four out of eight transformation events containing the <i>alk</i> gene, Alk-3, Alk-4, Alk-7 and Alk-9, were self-pollinated to T4/T6 generations. At T3, the Alk-transgenic lines showed up to 87% reduction in aflatoxin accumulation under laboratory conditions. T4 transgenic Alk-3 and Alk-7 lines, and T5 and T6 Alk-4 and Alk-9 showed an average of 84% reduction in aflatoxin accumulation compared to their null controls under field inoculations (<i>p</i> < 0.05). F<sub>1</sub> hybrids of three elite maize inbred lines and the transgenic lines also showed significant improvement in aflatoxin resistance (<i>p</i> < 0.006 to <i>p</i> < 0.045). Reduced <i>A. flavus</i> growth and levels of fungal <i>ß-tubulin</i> DNA were observed in transgenic kernels during in vitro inoculation. Alk-4 transgenic leaf and immature kernel tissues also contained about 1000-fold higher levels of <i>alk</i>-specific small RNAs compared to null controls, indicating that the enhanced aflatoxin resistance in the transgenic maize kernels is due to suppression of <i>A. flavus</i> infection through HIGS of <i>alk</i> gene. |
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| publishDate | 2021-10-01 |
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| spelling | doaj.art-f3c34a0d00c94124b0e7291fa3af2aed2023-11-22T23:55:12ZengMDPI AGJournal of Fungi2309-608X2021-10-0171190410.3390/jof7110904Resistance to Aflatoxin Accumulation in Maize Mediated by Host-Induced Silencing of the <i>Aspergillus flavus</i> Alkaline Protease (<i>alk</i>) GeneOlanike Omolehin0Yenjit Raruang1Dongfang Hu2Zhu-Qiang Han3Qijian Wei4Kan Wang5Kanniah Rajasekaran6Jeffrey W. Cary7Zhi-Yuan Chen8Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USADepartment of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USADepartment of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USACash Crops Research Institute, Guangxi Academy of Agricultural Sciences, Nanning 530007, ChinaFood and Feed Safety Research Unit, Southern Regional Research Center, United States Department of Agriculture—Agricultural Research Service, New Orleans, LA 70124, USADepartment of Agronomy, Iowa State University, Ames, IA 50011, USAFood and Feed Safety Research Unit, Southern Regional Research Center, United States Department of Agriculture—Agricultural Research Service, New Orleans, LA 70124, USAFood and Feed Safety Research Unit, Southern Regional Research Center, United States Department of Agriculture—Agricultural Research Service, New Orleans, LA 70124, USADepartment of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA<i>Aspergillus flavus</i> is a fungal pathogen that infects maize and produces aflatoxins. Host-Induced Gene Silencing (HIGS) has been shown to reduce host infection by various fungal pathogens. Here, the <i>A. flavus</i> alkaline protease (<i>alk</i>) gene was targeted for silencing through HIGS. An RNAi vector carrying a portion of the <i>alk</i> gene was incorporated into the B104 maize genome. Four out of eight transformation events containing the <i>alk</i> gene, Alk-3, Alk-4, Alk-7 and Alk-9, were self-pollinated to T4/T6 generations. At T3, the Alk-transgenic lines showed up to 87% reduction in aflatoxin accumulation under laboratory conditions. T4 transgenic Alk-3 and Alk-7 lines, and T5 and T6 Alk-4 and Alk-9 showed an average of 84% reduction in aflatoxin accumulation compared to their null controls under field inoculations (<i>p</i> < 0.05). F<sub>1</sub> hybrids of three elite maize inbred lines and the transgenic lines also showed significant improvement in aflatoxin resistance (<i>p</i> < 0.006 to <i>p</i> < 0.045). Reduced <i>A. flavus</i> growth and levels of fungal <i>ß-tubulin</i> DNA were observed in transgenic kernels during in vitro inoculation. Alk-4 transgenic leaf and immature kernel tissues also contained about 1000-fold higher levels of <i>alk</i>-specific small RNAs compared to null controls, indicating that the enhanced aflatoxin resistance in the transgenic maize kernels is due to suppression of <i>A. flavus</i> infection through HIGS of <i>alk</i> gene.https://www.mdpi.com/2309-608X/7/11/904<i>Aspergillus flavus</i>host induced gene silencingalkaline protease (<i>alk</i>)aflatoxin resistancetransgenic maizesmall RNA |
| spellingShingle | Olanike Omolehin Yenjit Raruang Dongfang Hu Zhu-Qiang Han Qijian Wei Kan Wang Kanniah Rajasekaran Jeffrey W. Cary Zhi-Yuan Chen Resistance to Aflatoxin Accumulation in Maize Mediated by Host-Induced Silencing of the <i>Aspergillus flavus</i> Alkaline Protease (<i>alk</i>) Gene Journal of Fungi <i>Aspergillus flavus</i> host induced gene silencing alkaline protease (<i>alk</i>) aflatoxin resistance transgenic maize small RNA |
| title | Resistance to Aflatoxin Accumulation in Maize Mediated by Host-Induced Silencing of the <i>Aspergillus flavus</i> Alkaline Protease (<i>alk</i>) Gene |
| title_full | Resistance to Aflatoxin Accumulation in Maize Mediated by Host-Induced Silencing of the <i>Aspergillus flavus</i> Alkaline Protease (<i>alk</i>) Gene |
| title_fullStr | Resistance to Aflatoxin Accumulation in Maize Mediated by Host-Induced Silencing of the <i>Aspergillus flavus</i> Alkaline Protease (<i>alk</i>) Gene |
| title_full_unstemmed | Resistance to Aflatoxin Accumulation in Maize Mediated by Host-Induced Silencing of the <i>Aspergillus flavus</i> Alkaline Protease (<i>alk</i>) Gene |
| title_short | Resistance to Aflatoxin Accumulation in Maize Mediated by Host-Induced Silencing of the <i>Aspergillus flavus</i> Alkaline Protease (<i>alk</i>) Gene |
| title_sort | resistance to aflatoxin accumulation in maize mediated by host induced silencing of the i aspergillus flavus i alkaline protease i alk i gene |
| topic | <i>Aspergillus flavus</i> host induced gene silencing alkaline protease (<i>alk</i>) aflatoxin resistance transgenic maize small RNA |
| url | https://www.mdpi.com/2309-608X/7/11/904 |
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