黄曲霉毒素阻控与花生超级结瘤耦合效应研究初报

花生、大豆是我国重要的油料和经济作物，因易受黄曲霉毒素污染，严重威胁食品安全，制约产业发展，因此，黄曲霉毒素防控一直是国内外研究的热点难题。本团队首次提出将黄曲霉毒素绿色阻控与促进根瘤固氮耦合的研究思路，研发了生物菌剂ARC-BBBE，本文报道生物菌剂ARC-BBBE对黄曲霉毒素及其产毒菌阻控的大田应用效果，调查其对花生生物学性状及经济性状的影响，探索ARC-BBBE对花生、大豆根系结瘤及根瘤固氮的影响，为从田间源头阻控黄曲霉毒素及促进根瘤固氮、实现减肥减药提供理论依据和科学指导。连续2年在我国花生主产省开展田间防控试验，将绿色阻控生物菌剂ARC-BBBE于花生播种期以30 kg/hm²用量与基肥一起撒施于土壤中。同时开展室内花生、大豆盆栽试验。使用涂布法调查土壤中黄曲霉毒素产毒菌丰度，使用高效液相色谱法检测花生样品中黄曲霉毒素，使用乙炔还原法测定根瘤固氮活性，采用5点取样法调查统计根瘤数、根瘤重。结果表明，应用ARC-BBBE显著降低了土壤中黄曲霉毒素产毒菌的丰度（平均降低66.5%）和花生中黄曲霉毒素的含量（平均降低83.5%）。应用ARC-BBBE后，花生根系普遍出现超级结瘤现象，实验验证表明其根瘤具有固氮活性，平均结瘤数增加10倍以上（土壤贫瘠地区50倍以上），瘤重增加8.8倍，每克根瘤固氮酶活性提高5倍以上。饱果率、产量均明显提高，叶色浓绿。花生室内盆栽结果表明，ARC-BBBE处理组根系结瘤数是对照组的2.2倍，固氮酶活性是对照组的4倍，叶绿素含量较对照组增加21.3%。大豆室内盆栽苗期实验结果表明，ARC-BBBE同样可诱发大豆结瘤及固氮效应：播种后第26天，处理组瘤数增加13.5倍、瘤重增加19.8倍；而且处理组有固氮活性，而对照组无固氮活性；苗期处理组的根长、根重、鲜重、叶绿素等生物学指标显著提升。ARC-BBBE对花生黄曲霉毒素及其产毒菌污染阻控效果极为明显，既可从生产源头有效阻控花生黄曲霉毒素产毒菌，降低黄曲霉毒素污染风险，同时大幅增加了花生根瘤数量和固氮酶活性，具有显著的促生长、增产量、控病害、保安全作用，具有显著的经济、社会、生态效益。对未来减施农药、化肥，保护农田生态，推动花生、大豆产业高质量绿色发展具有重要意义，在花生、大豆等豆科作物生产中应用前景广阔。

A preliminary study on the coupling effect of aflatoxin green control and super-nodulation

Peanut and soybean are important oilseeds and cash crops in China, however they are also vulnerable to aflatoxin contamination, which seriously threatens food safety and restricts industrial development. The prevention and control of aflatoxin occurrence in food is currently an intense research challenge globally. We first put forward the research idea of coupling the aflatoxin green control with the promotion of root nodule nitrogen fixation, based on the research idea, the microbial agent ARC-BBBE was invented. In this study, the effect of on-the-field application of microbial agent ARC-BBBE in the control of Aspergillus flavus and its toxin on peanut was reported. The research was carried out by investigating the effects of ARC-BBBE on biological and economic traits of peanut, and identifying the effects of ARC-BBBE on nodulation and nitrogen fixation of peanut and soybean, to provide theoretical basis and scientific guidance for controlling aflatoxin contamination and reducing the fertilizer and pesticide use from the source in the field. In field control trials, ARC-BBBE was applied to the soil at a dosage of 30 kg/hm² with base fertilizer during planting in the peanut-producing provinces of China for 2 consecutive years. At the same time, peanut and soybean pot experiments were also conducted. The level of aflatoxin in the soil was investigated by the spread plate method. And the aflatoxin content in peanut samples was determined using high performance liquid chromatography （HPLC）. Measurement of the nitrogen fixation activity of root nodules was performed using acetylene reduction assay. Finally, the number and weight of root nodules were calculated using a 5-point sampling survey. Results showed that ARC-BBBE significantly reduced the abundance of aflatoxin-producing fungi in soil and the level of aflatoxin in peanut, with an average reduction of 66.5% in the abundance of toxin-producing fungi and decrease of 83.5% in aflatoxin content. The application of ARC-BBBE resulted in a general super nodulation phenomenon in peanut roots, and its nitrogenase activity was also verified in this work. The average number of nodules increased more than 10 folds （50 folds in poor soil areas）, the nodule weight increased more than 8.8 folds, and the nodule nitrogenase activity per gram increased more than 5 folds. The fruit filling rate and yield were significantly increased and the leaf color was dense green. In addition, the results of peanut pot experiment in greenhouse showed that the number of nodules was 2.2 folds higher, nitrogen fixing enzyme activity was 4 folds higher and chlorophyll content was 21.3% higher in the ARC-BBBE treated group compared to the control group. The results of soybean potted planting experiment in greenhouse revealed that ARC-BBBE also promoted nodulation and nitrogen fixation in soybean, with a 13.5-fold increase in the number of nodules and a 19.8-fold increase in nodule weight in the ARC-BBBE-treated group compared to the control group. At 26 days after sowing, the root nodules in the treatment group had nitrogen fixation activity while those in the control group had no activity, and biological indices such as root length, root weight, fresh weight and chlorophyll level were significantly enhanced in the treatment group. The effect of ARC-BBBE on the control of Aspergillus flavus and its toxin in peanut is extremely obvious. ARC-BBBE does not only effectively inhibit peanut aflatoxin-producing fungi and reduce the risk of aflatoxin contamination from the source of production, but also significantly improves the amount of peanut root nodules and nitrogen-fixing enzyme activity, which is of remarkable growth-promoting, yield-increasing, disease-control, safety-preserving properties, and economic, social and ecological benefits. Thus, it is of great significance in minimizing the application of pesticides and fertilizers, protecting farmland ecology, and promoting the high-quality environment-friendly development of the peanut industry, which is prospective for application in the production of peanut, soybean and other leguminous crops in the future.