Mazumdar Tilottama, Hänniger Sabine, Shukla Shantanu P, Murali Aishwarya, Bartram Stefan, Heckel David G, Boland Wilhelm
Department of Zoology, Institute of Zoology, Freie Universität Berlin, Berlin, Germany.
Department of Entomology, Max Planck Institute for Chemical Ecology, Jena, Germany.
Front Microbiol. 2023 Jan 18;14:1075557. doi: 10.3389/fmicb.2023.1075557. eCollection 2023.
Quinolinic carboxylic acids are known for their metal ion chelating properties in insects, plants and bacteria. The larval stages of the lepidopteran pest, , produce 8-hydroxyquinoline-2-carboxylic acid (8-HQA) in high concentrations from tryptophan in the diet. At the same time, the larval midgut is known to harbor a bacterial population. The motivation behind the work was to investigate whether 8-HQA is controlling the bacterial community in the gut by regulating the concentration of metal ions. Knocking out the gene for kynurenine 3-monooxygenase (KMO) in the insect using CRISPR/Cas9 eliminated production of 8-HQA and significantly increased bacterial numbers and diversity in the larval midgut. Adding 8-HQA to the diet of knockout larvae caused a dose-dependent reduction of bacterial numbers with minimal effects on diversity. dominates the community in all treatments, probably due to its highly efficient iron uptake system and production of the colicin, mundticin. Thus host factors and bacterial properties interact to determine patterns of diversity and abundance in the insect midgut.
喹啉羧酸因其在昆虫、植物和细菌中的金属离子螯合特性而闻名。鳞翅目害虫的幼虫阶段会从饮食中的色氨酸大量产生8-羟基喹啉-2-羧酸（8-HQA）。同时，已知幼虫中肠中存在细菌群体。这项工作的动机是研究8-HQA是否通过调节金属离子浓度来控制肠道中的细菌群落。使用CRISPR/Cas9敲除昆虫中的犬尿氨酸3-单加氧酶（KMO）基因消除了8-HQA的产生，并显著增加了幼虫中肠中的细菌数量和多样性。在基因敲除幼虫的饮食中添加8-HQA导致细菌数量呈剂量依赖性减少，对多样性的影响最小。在所有处理中， 均在群落中占主导地位，这可能是由于其高效的铁摄取系统和大肠杆菌素mundticin的产生。因此，宿主因素和细菌特性相互作用，以确定昆虫中肠中多样性和丰度的模式。
