U.S. Department of Agriculture, Agricultural Research Service, Western Regional Research Center, 800 Buchanan Street, Albany, CA 94710, USA.
U.S. Department of Agriculture, Agricultural Research Service, Southern Regional Research Center, 1100 Robert E. Boulevard, New Orleans, LA 70124, USA.
Toxins (Basel). 2019 Feb 1;11(2):81. doi: 10.3390/toxins11020081.
is a ubiquitous saprophytic fungus found in soils across the world. The fungus is the major producer of aflatoxin (AF) B₁, which is toxic and a potent carcinogen to humans. Aflatoxin B₁ (AFB₁) is often detected in agricultural crops such as corn, peanut, almond, and pistachio. It is a serious and recurrent problem and causes substantial economic losses. WRL-076 was identified as an effective biocontrol yeast against . In this study, the associated molecular mechanisms of biocontrol were investigated. We found that the expression levels of eight genes, , , , , , , , and in the aflatoxin biosynthetic pathway cluster were suppressed. The decreases ranged from several to 10,000 fold in fungal samples co-cultured with . Expression levels of conidiation regulatory genes , , and as well as sclerotial regulatory gene () were all down regulated. Consistent with the decreased gene expression levels, aflatoxin concentrations in cultural medium were reduced to barely detectable. Furthermore, fungal biomass and conidial number were significantly reduced by 60% and more than 95%, respectively. The results validate the biocontrol efficacy of WRL-076 observed in the field experiments.
是一种普遍存在的腐生真菌，存在于世界各地的土壤中。该真菌是黄曲霉毒素（AF）B₁的主要生产者，黄曲霉毒素 B₁（AFB₁）对人类具有毒性和强烈的致癌性。黄曲霉毒素 B₁（AFB₁）经常在玉米、花生、杏仁和开心果等农作物中被检测到。这是一个严重且反复出现的问题，会造成巨大的经济损失。WRL-076 被鉴定为一种有效的生防酵母，可对抗。在这项研究中，我们研究了生防的相关分子机制。我们发现，黄曲霉生物合成途径簇中八个基因的表达水平被抑制。在与共培养的真菌样本中，基因的表达水平下降了几个到 10000 倍。分生孢子调控基因、和以及菌核调控基因（）的表达水平均下调。与基因表达水平的降低一致，培养基中的黄曲霉毒素浓度降低到几乎无法检测到的水平。此外，真菌生物量和分生孢子数分别减少了 60%和 95%以上。这些结果验证了 WRL-076 在田间试验中观察到的生防效果。
