Bui Van Cuong, Franken Philipp
Leibniz-Institute of Vegetable and Ornamental Crops, Großbeeren, Germany.
Institute of Environmental Technology, Vietnam Academy of Science and Technology, Hanoi, Vietnam.
Front Microbiol. 2018 Dec 18;9:3156. doi: 10.3389/fmicb.2018.03156. eCollection 2018.
Arbuscular mycorrhizal (AM) fungi confer heavy metal tolerance to plants, but this characteristic differs between different AM fungal strains. We tested the hypotheses if acclimatization of an AM fungus to Zn stress is possible and if this leads also to higher Zn tolerance of mycorrhizal plants. The AM fungus was acclimatized in root organ cultures ( L.) to Zn resulting in an acclimatized (Acc+) strain. The non-acclimatized (Acc-) strain remained untreated. Fungal development and RNA accumulation of a set of stress-related genes were analyzed in root organ cultures and the capacity of conferring Zn tolerance to maize plants was investigated in pot cultures. Development of Acc+ strain was significantly higher than Acc- strain, when strains were grown in Zn-enriched root organ cultures, whereas the growth of the Acc+ strain was reduced on normal medium probably due to a higher Zn demand compared to the Acc- strain. RNA accumulation analyses revealed different expression patterns of genes encoding glutathione S-transferase (), superoxide dismutase () and glutaredoxin () between the two strains. Plants inoculated with the Acc+ strain showed higher biomass and lower Zn content than those inoculated with the Acc- strain. The results showed that can be acclimatized to increased amounts of Zn. This acclimatization leads not only to improved fungal development in Zn-stress conditions, but also to an increase of mycorrhiza-induced Zn tolerance of colonized plants.
丛枝菌根（AM）真菌可赋予植物重金属耐受性，但这种特性在不同的AM真菌菌株之间存在差异。我们检验了以下假设：AM真菌是否有可能适应锌胁迫，以及这是否也会导致菌根植物对锌的耐受性提高。将AM真菌在根器官培养物（L.）中适应锌，从而获得适应（Acc+）菌株。未适应（Acc-）的菌株未作处理。在根器官培养物中分析了一组与胁迫相关基因的真菌发育和RNA积累情况，并在盆栽培养中研究了赋予玉米植株锌耐受性的能力。当菌株在富含锌的根器官培养物中生长时，Acc+菌株的发育明显高于Acc-菌株，而Acc+菌株在正常培养基上的生长可能由于与Acc-菌株相比对锌的需求更高而受到抑制。RNA积累分析揭示了两种菌株之间编码谷胱甘肽S-转移酶（）、超氧化物歧化酶（）和谷氧还蛋白（）的基因的不同表达模式。接种Acc+菌株的植物比接种Acc-菌株的植物表现出更高的生物量和更低的锌含量。结果表明，（此处英文原文有误，推测可能是AM真菌相关内容）可以适应增加的锌含量。这种适应不仅导致在锌胁迫条件下真菌发育得到改善，而且还导致定殖植物的菌根诱导锌耐受性增加。
