Omolehin Olanike, Raruang Yenjit, Hu Dongfang, Han Zhu-Qiang, Promyou Surassawadee, Brown Robert L, Wei Qijian, Rajasekaran Kanniah, Cary Jeffrey W, Wang Kan, Jeffers Dan, Chen Zhi-Yuan
Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture (USDA/ARS), New Orleans, LA 70124, USA.
Toxins (Basel). 2024 Dec 27;17(1):8. doi: 10.3390/toxins17010008.
Maize is one of the major crops that are susceptible to infection and subsequent aflatoxin contamination, which poses a serious health threat to humans and domestic animals. Here, an RNA interference (RNAi) approach called Host-Induced Gene Silencing (HIGS) was employed to suppress the -methyl transferase gene (, also called ), a key gene involved in aflatoxin biosynthesis. An RNAi vector carrying part of the gene was introduced into the B104 maize line. Among the six transformation events that were positive for containing the transgene, OmtA-6 and OmtA-10 were self-pollinated from T1 to T4, and OmtA-7 and OmtA-12 to the T6 generation. These four lines showed at least an 81.3% reduction in aflatoxin accumulation at the T3 generation under laboratory conditions. When screened under field conditions with artificial inoculation, OmtA-7 at T5 and T6 generations and OmtA-10 at T4 generation showed a reduction in aflatoxin contamination between 60% and 91% ( < 0.02 to < 0.002). In order to develop commercial maize lines with enhanced aflatoxin resistance, the transgene in OmtA-7 was introduced into three elite inbred lines through crossing, and the resulting crosses also exhibited significantly lower aflatoxin accumulation compared to crosses with non-transgenic controls ( < 0.04). In addition, high levels of -specific small RNAs were only detected in the transgenic kernel and leaf tissues. These results demonstrate that suppression of through HIGS can enhance maize resistance to aflatoxin contamination, and this resistance can be transferred to elite backgrounds, providing a viable and practical approach to reduce aflatoxin contamination in maize.
玉米是易受感染并随后遭受黄曲霉毒素污染的主要作物之一，这对人类和家畜构成严重的健康威胁。在此，采用了一种名为宿主诱导基因沉默（HIGS）的RNA干扰（RNAi）方法来抑制参与黄曲霉毒素生物合成的关键基因——O-甲基转移酶基因（omtA，也称为aflR）。将携带omtA基因部分片段的RNAi载体导入B104玉米品系。在六个含有omtA转基因呈阳性的转化事件中，OmtA-6和OmtA-10从T1代自交到T4代，OmtA-7和OmtA-12自交到T6代。在实验室条件下，这四个品系在T3代时黄曲霉毒素积累至少减少了81.3%。在人工接种的田间条件下筛选时，T5代和T6代的OmtA-7以及T4代的OmtA-10的黄曲霉毒素污染减少了60%至91%（P<0.02至P<0.002）。为了培育具有增强黄曲霉毒素抗性的商业玉米品系，通过杂交将OmtA-7中的omtA转基因导入三个优良自交系，与非转基因对照杂交的后代相比，所得杂交后代的黄曲霉毒素积累也显著降低（P<0.04）。此外，仅在转基因籽粒和叶片组织中检测到高水平的omtA特异性小RNA。这些结果表明，通过HIGS抑制omtA可增强玉米对黄曲霉毒素污染的抗性，并且这种抗性可以转移到优良背景中，为减少玉米中的黄曲霉毒素污染提供了一种可行且实用的方法。
