National Key Laboratory for Germplasm Innovation and Utilization for Fruit and Vegetable Horticultural Crops, Hubei Hongshan Laboratory, China-Australia Joint Research Centre for Horticultural and Urban Pests, Institute of Urban and Horticultural Entomology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
College of Plant Protection, Yangzhou University, Yangzhou, 225009, China.
Microbiome. 2024 Nov 4;12(1):227. doi: 10.1186/s40168-024-01931-9.
The gut microbiota can facilitate host growth under nutrient-constrained conditions. However, whether this effect is limited to certain bacterial species remains largely unclear, and the relevant underlying mechanisms remain to be thoroughly investigated.
We found that the microbiota was required for Bactrocera dorsalis larval growth under poor dietary conditions. Monoassociation experiments revealed that Enterobacteriaceae and some Lactobacilli promoted larval growth. Among the 27 bacterial strains tested, 14 significantly promoted larval development, and the Enterobacteriaceae cloacae isolate exhibited the most obvious promoting effect. A bacterial genome-wide association study (GWAS) revealed that the vitamin B6 synthesis pathway was critical for the promotion of E. cloacae growth. Deletion of pdxA, which is responsible for vitamin B6 biosynthesis, deprived the mutant strains of larval growth-promoting function, indicating that the 4-hydroxythreonine-4-phosphate dehydrogenase(pdxA) gene was crucial for promoting larval growth in E. cloacae. Importantly, supplementation of a poor diet with vitamin B6 successfully rescued the axenic larval growth phenotype of B. dorsalis.
Our results suggest that gut microbes promote insect larval growth by providing vitamin B6 under nutrient scarcity conditions in B. dorsalis. Video Abstract.
肠道微生物群可以在营养受限的条件下促进宿主生长。然而，这种效应是否仅限于某些细菌种类在很大程度上仍不清楚，相关的潜在机制仍有待彻底研究。
我们发现，在较差的饮食条件下，微生物群是丽蝇幼虫生长所必需的。单联实验表明，肠杆菌科和一些乳杆菌促进了幼虫的生长。在测试的 27 株细菌中，有 14 株显著促进了幼虫的发育，其中肠杆菌科的阴沟肠杆菌分离株表现出最明显的促进作用。一项细菌全基因组关联研究（GWAS）表明，维生素 B6 的合成途径对阴沟肠杆菌生长的促进作用至关重要。pdxA 缺失，负责维生素 B6 生物合成，使突变株丧失了促进幼虫生长的功能，表明 4-羟脯氨酸-4-磷酸脱氢酶（pdxA）基因对促进阴沟肠杆菌幼虫生长至关重要。重要的是，在缺乏营养的饮食中补充维生素 B6 成功地挽救了丽蝇幼虫的无菌生长表型。
我们的结果表明，肠道微生物通过在丽蝇幼虫中提供维生素 B6 来促进其在营养匮乏条件下的生长。
