Truffles are highly valuable ectomycorrhizal fungi that grow naturally in alkaline, calcareous soils. Iron deficiency chlorosis is a common problem in truffle (Tuber spp.) cultivation due to the high quantity of lime added to increase the pH of acidic soils. In this work, the effects of ferric hydroxide nanoparticles embedded in an exopolysaccharide (Fe-EPS NPs), extracted from cultures of Klebsiella oxytoca DSM 29614, were investigated on Quercus robur seedlings under greenhouse conditions. The plants were inoculated with Tuber borchii (the bianchetto truffle) and were cultivated with and without iron nanoparticle additions and compared with non-inoculated control plants. The seedlings were grown in limed soil in order to induce iron deficiency. Low doses of Fe-EPS NPs had a beneficial effect on the growth of the plants inoculated with T. borchii, increasing their height and reducing their leaf chlorosis 5 months after the first Fe-EPS NP treatment. Moreover, Fe-EPS NP treatments significantly increased the level of T. borchii mycorrhizal colonization and the ectomycorrhizal mantle thickness. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) applied to cross sections of mycorrhizas showed that Fe accumulated in the fungal mantle and apparently was slowly released serving as a resilient reservoir of iron for the plant. The results suggest that the application of Fe-EPS NPs is a promising technique in the production of Tuber mycorrhized plants in the nursery and could have future applications in the field.

中文翻译：

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生物生成的氢氧化铁纳米颗粒对松露菌根植物的影响。

松露是极有价值的外生菌根真菌，可在碱性钙质土壤中自然生长。缺铁萎黄是在松露一个共同的问题（块茎种植属）由于加入以提高酸性土壤的pH石灰的高量。在这项工作中，嵌入式氢氧化铁纳米颗粒的影响在胞外多糖（FE-EPS NPS），从培养物中提取产酸克雷伯菌DSM 29614，考察了夏栎温室条件下苗。用马铃薯块茎接种植物（比安科托松露）（Bianchetto松露）进行培养，并添加和不添加铁纳米颗粒，并与未接种的对照植物进行比较。幼苗在石灰土壤中生长，以诱导铁缺乏。在首次Fe-EPS NP处理后5个月，低剂量的Fe-EPS NPs对接种博来螺旋藻的植物的生长具有有益的作用，增加了其高度并减少了叶绿化。此外，Fe-EPS NP治疗显着提高了博尔希氏锥虫的水平菌根定植和外生菌根套厚度。应用于菌根横截面的激光消融电感耦合等离子体质谱法（LA-ICP-MS）表明，Fe积累在真菌地幔中，并且显然释放缓慢，从而为植物提供了铁的弹性储库。结果表明，Fe-EPS NPs的应用是育苗块茎菌根植物生产中的一种有前途的技术，并且可能在该领域中有未来的应用。