Sweany Rebecca R, Damann Kenneth E
Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA, United States.
Front Microbiol. 2020 Jan 15;10:3038. doi: 10.3389/fmicb.2019.03038. eCollection 2019.
is an ascomycete fungus that infects and contaminates corn, peanuts, cottonseed, and treenuts with acutely toxic and carcinogenic aflatoxins. The ecological function of aflatoxin production is not well understood; though not phytotoxic, aflatoxin may be involved in resisting oxidative stress responses from infection or drought stress in plants. Observation of aflatoxin stimulation in 48-well plates in response to increasing inoculated wells sparked an investigation to determine if volatiles influence aflatoxin production in neighboring colonies. Experiments controlling several culture conditions demonstrated a stimulation of aflatoxin production with increased well occupancy independent of pH buffer, moisture, or isolate. However, even with all wells inoculated, aflatoxin production was less in interior wells. Only one isolate stimulated aflatoxin production in a large Petri-dish format containing eight small Petri dishes with shared headspace. Other isolates consistently inhibited aflatoxin production when all eight Petri dishes were inoculated with . No contact between cultures and only shared headspace implied the fungus produced inhibitory and stimulatory gases. Adding activated charcoal between wells and dishes prevented inhibition but not stimulation indicating stimulatory and inhibitory gases are different and/or gas is inhibitory at high concentration and stimulatory at lower concentrations. Characterizing stimulatory and inhibitory effects of gases in headspace as well as the apparently opposing results in the two systems deserves further investigation. Determining how gases contribute to quorum sensing and communication could facilitate managing or using the gases in modified atmospheres during grain storage to minimize aflatoxin contamination.
是一种子囊菌真菌，它会用剧毒且致癌的黄曲霉毒素感染和污染玉米、花生、棉籽和坚果。黄曲霉毒素产生的生态功能尚不清楚；尽管黄曲霉毒素对植物没有毒性，但它可能参与抵抗植物感染或干旱胁迫引起的氧化应激反应。在48孔板中观察到随着接种孔数量增加黄曲霉毒素受到刺激，这引发了一项调查，以确定挥发性物质是否会影响相邻菌落中黄曲霉毒素的产生。控制多种培养条件的实验表明，随着孔占有率的增加，黄曲霉毒素的产生受到刺激，这与pH缓冲液、湿度或分离株无关。然而，即使所有孔都接种了，内部孔中的黄曲霉毒素产量也较低。只有一种分离株在一个大培养皿中刺激了黄曲霉毒素的产生，该培养皿包含八个共享顶部空间的小培养皿。当所有八个培养皿都接种时，其他分离株始终抑制黄曲霉毒素的产生。培养物之间没有接触，只有共享的顶部空间，这意味着真菌产生了抑制性和刺激性气体。在孔和培养皿之间添加活性炭可以防止抑制，但不能防止刺激，这表明刺激性和抑制性气体不同，和/或气体在高浓度时具有抑制作用，在低浓度时具有刺激作用。表征顶部空间中气体的刺激和抑制作用以及两个系统中明显相反的结果值得进一步研究。确定气体如何影响群体感应和通讯，可能有助于在谷物储存期间在改良气氛中管理或利用这些气体，以尽量减少黄曲霉毒素污染。
