Roshanfekrrad Marjan, Papadopoulos Christos, Calonne-Salmon Maryline, Schneider Carolin, Zhang Kunyang, Karpouzas Dimitrios, Declerck Stephan
Universite Catholique de Louvain, Earth and Life Institute, Croix du Sud 2, Box L7.05.06, Mycology, Louvain‑La‑Neuve, 1348, Belgium.
INOQ GmbH, Solkau 2, 29465, Schnega, Germany.
Mycorrhiza. 2025 May 16;35(3):38. doi: 10.1007/s00572-025-01211-w.
Pesticides are essential agricultural inputs that help securing crop yields. However, they can affect non-target soil microorganisms, including arbuscular mycorrhizal (AM) fungi, that are potential indicators of the toxicity of pesticides on the soil microbiota. Here, we developed a fast-track high-throughput spore germination test, for AM fungi produced in vitro. This test allows the determination of EC values and the nature of the effects of pesticides on AM fungal spores (fungicidal or fungistatic). First, 19 active ingredients were tested on Rhizophagus intraradices MUCL 49410. Secondly, five of these compounds, varying in their toxicity to R. intraradices, were tested on three additional AM fungi (Rhizophagus irregularis MUCL 41833, Rhizophagus clarus MUCL 46238 and Rhizophagus aggregatus MUCL 49408). Our results showed that the toxicity of pesticides varied according to their chemical nature, concentration and AM fungal species tested. With the exception of 3,5,6-trichloro-2-pyridinol (TCP, a transformation product of chlorpyrifos), insecticides and herbicides had no detrimental effect on spore germination at the concentration expected in soil upon application of the recommended dose, unlike most fungicides, which had an impact on one or more AM fungi. Fludioxonil and pyraclostrobin were by far the most problematic fungicide and R. aggregatus the most sensitive strain to pesticides. This AM fungus could thus be a good indicator to be used in standard ecotoxicity testing. In conclusion, we present a fast-track, high-throughput testing system for assessing the toxicity of pesticides on AM fungi, using spore germination as a relevant endpoint, that could be used as a first-tier screening tool in pesticide risk assessment.
农药是保障作物产量的重要农业投入品。然而，它们会影响非靶标土壤微生物，包括丛枝菌根（AM）真菌，而AM真菌是农药对土壤微生物群毒性的潜在指示生物。在此，我们开发了一种针对体外培养的AM真菌的快速高通量孢子萌发试验。该试验能够确定农药对AM真菌孢子的半数有效浓度（EC值）及其作用性质（杀菌或抑菌）。首先，对19种活性成分进行了针对根内根孢囊霉MUCL 49410的测试。其次，从这19种化合物中选取了5种对根内根孢囊霉毒性不同的化合物，对另外三种AM真菌（不规则根孢囊霉MUCL 41833、明根孢囊霉MUCL 46238和聚集根孢囊霉MUCL 49408）进行了测试。我们的结果表明，农药的毒性因其化学性质、浓度以及所测试的AM真菌种类而异。除了3,5,6 - 三氯 - 2 - 吡啶醇（TCP，毒死蜱的一种转化产物）外，与大多数对一种或多种AM真菌有影响的杀菌剂不同，杀虫剂和除草剂在按照推荐剂量施用于土壤后预期的浓度下对孢子萌发没有不利影响。咯菌腈和吡唑醚菌酯是目前最具问题的杀菌剂，而聚集根孢囊霉是对农药最敏感的菌株。因此，这种AM真菌可作为标准生态毒性测试中的良好指示生物。总之，我们提出了一种快速、高通量的测试系统，以孢子萌发作为相关终点来评估农药对AM真菌的毒性，该系统可作为农药风险评估中的一级筛选工具。
