Leibniz Institute of Freshwater Ecology and Inland Fisheries, Department of Aquaculture and Ecophysiology, Müggelseedamm 301, 12587 Berlin, Germany.
Toxicon. 2010 Sep 1;56(3):411-7. doi: 10.1016/j.toxicon.2010.04.004. Epub 2010 Apr 14.
Spray irrigation of crop plants can represent a risk if the water is contaminated with cyanotoxins. These secondary metabolites produced by many cyanobacteria can have adverse effects on organisms, among others the induction of excess oxygen radicals, so-called oxidative stress. Thereby tocopherol as a lipid antioxidant is essential to maintain membrane integrity. In this study the effects of the cyanotoxin microcystin-LR (MC-LR), and a Microcystis crude extract (Mic-CE) containing MC-LR on tocopherol content and gene expression of Homogentisate phytyltransferase (HPT), involved in tocopherol synthesis, were investigated in seedlings of the crop plant Medicago sativa. Exposures to environmental relevant concentrations showed that Mic-CE affects the tocopherols at a lower concentration than the pure toxin. Changes during a 3-day exposure using 0.5mug L(-1) MC-LR and Mic-CE revealed strong increases of alpha- and beta-tocopherol content, whereas the influence on beta-tocopherol was far stronger than on alpha-tocopherol. The HPT mRNA was elevated after 24 and 72h exposure to MC-LR. These results show that also low concentrations of cyanobacterial toxins in the water have strong influence on tocopherol in M. sativa seedlings and therefore represent a stress for the plants.
如果作物植物的水受到蓝藻毒素的污染，喷雾灌溉可能会带来风险。这些由许多蓝藻产生的次生代谢物会对生物体产生不良影响，其中包括诱导过多的氧自由基，即所谓的氧化应激。因此，生育酚作为一种脂溶性抗氧化剂对于维持膜的完整性是必不可少的。在这项研究中，研究了蓝藻毒素微囊藻毒素-LR（MC-LR）和含有 MC-LR 的微囊藻粗提取物（Mic-CE）对作物植物紫花苜蓿幼苗生育酚含量和参与生育酚合成的对羟基苯丙氨酸植基转移酶（HPT）基因表达的影响。暴露于环境相关浓度下表明，Mic-CE 以低于纯毒素的浓度影响生育酚。使用 0.5μg L（-1）MC-LR 和 Mic-CE 进行为期 3 天的暴露期间的变化表明，α-和β-生育酚含量大幅增加，而β-生育酚的影响远强于α-生育酚。暴露于 MC-LR 24 和 72 小时后，HPT mRNA 升高。这些结果表明，水中低浓度的蓝藻毒素也会对紫花苜蓿幼苗中的生育酚产生强烈影响，因此对植物构成压力。
