Department of Biology, Ecology and Earth Science, University of Calabria, Via Bucci, 87036, Arcavacata di Rende, Cosenza, Italy; Animal Evolutionary Ecology Group, Institute for Evolution and Biodiversity, Universityof Münster, Hüferstr. 1, 48149, Münster, Germany.
Animal Evolutionary Ecology Group, Institute for Evolution and Biodiversity, Universityof Münster, Hüferstr. 1, 48149, Münster, Germany; Institute for Biology, Freie Universität Berlin, Königin-Luise Str. 1-3, 14 195, Berlin, Germany.
Environ Pollut. 2023 Dec 1;338:122662. doi: 10.1016/j.envpol.2023.122662. Epub 2023 Sep 29.
Concerns have grown worldwide about the potentially far-reaching effects of herbicides on functional biodiversity in agroecosystems. Repeated applications over time can lead to accumulation of residues in soil, water, and food and may have negative impacts on non-target organisms. However, the effects of herbicide residues on interspecific relationships, such as host-pathogen interactions, are poorly studied. In this study, we evaluated the effects of two different concentrations of a commercial pendimethalin-based formulation (PND), the residual contamination (S, 13 ppm) in treated soils and the maximum residue level allowed by the European Commission in cereals (EU, 0.05 ppm). We tested the effect of PND on the biological interaction between the mealworm beetle Tenebrio molitor Linnaeus, 1758 and the entomopathogenic fungus Beauveria bassiana Vuillemin, 1912 (Bb, strain KVL 03-144) at two concentrations (LC 5 × 10 conidia mL and LC 1 × 10 conidia mL). We checked the survival of beetles exposed to PND or/and inoculated with B. bassiana, the expression of four antimicrobial peptides (AMPs), and finally how PND affects in vitro germination of fungus. The exposure to PND had no significant effects on the survival of either control or Bb-exposed beetles. In the mealworm beetle, upregulation of gene expression of the inducible AMPs Tenecin 1, 2, and 4 was observed in PND-treated beetles after inoculation with Bb, while the levels of the non-inducible AMP Tenecin 3 were similar between treatments. In conclusion, our findings demonstrate that admitted residual doses of currently used herbicides modify an important component of the inducible immune response of an insect. This did not translate into an effect on the survival to B. bassiana in our system. However, residual doses of the herbicide at 13 ppm may temporarily affect fungal germination. These results raise questions about the compatibility of bioinsecticides with synthetic pesticides and the effects of herbicide residues on host-pathogen interactions.
人们对除草剂在农业生态系统中对功能生物多样性可能产生的深远影响表示担忧。随着时间的推移，重复使用可能会导致土壤、水和食物中残留的积累，并可能对非目标生物产生负面影响。然而，除草剂残留对种间关系（如宿主-病原体相互作用）的影响研究甚少。在这项研究中，我们评估了两种不同浓度的商业丙草胺制剂（PND）、处理土壤中的残留污染（S，13ppm）和欧洲委员会允许在谷物中残留的最高水平（EU，0.05ppm）对鞘翅目幼虫黄粉虫 Tenebrio molitor Linnaeus, 1758 和昆虫病原真菌球孢白僵菌 Beauveria bassiana Vuillemin, 1912（Bb，菌株 KVL 03-144）之间生物相互作用的影响。我们在两个浓度（LC 5 × 10 个孢子 mL 和 LC 1 × 10 个孢子 mL）下测试了 PND 对黄粉虫的生存、暴露于 PND 或/和接种 B. bassiana 的幼虫的抗菌肽（AMPs）表达的影响，最后研究了 PND 如何影响真菌的体外萌发。暴露于 PND 对对照或暴露于 Bb 的甲虫的生存没有显著影响。在黄粉虫中，在接种 Bb 后，PND 处理的甲虫中诱导型 AMPs Tenecin 1、2 和 4 的基因表达上调，而非诱导型 AMP Tenecin 3 的水平在处理之间相似。总之，我们的研究结果表明，目前使用的除草剂的允许残留剂量会改变昆虫诱导免疫反应的一个重要组成部分。这在我们的系统中并没有转化为对 B. bassiana 存活的影响。然而，13ppm 的除草剂残留剂量可能会暂时影响真菌的萌发。这些结果引发了关于生物杀虫剂与合成农药的相容性以及除草剂残留对宿主-病原体相互作用的影响的问题。
