The use of Caenorhabditis elegans model to screen lactobacilli for the control of patulin

Patulin, a type of mycotoxin, presents a serious threat to human and animal health. Lactic acid bacteria (LAB) have been shown to effectively detoxify patulin and have strong application prospects in this regard. However, the efficient selection of LAB with patulin detoxification, especially in vivo, requires costly animal experiments. The nematode Caenorhabditis elegans is an ideal model for the prescreening of probiotics and for toxicity evaluation studies. In the present study, 15 LAB isolates were evaluated for their protection of C. elegans against patulin exposure, and only three strains-Lacticaseibacillus casei ZM4, Lactobacillus johnsonii PC4, and Lactiplantibacillus plantarum subsp. plantarum M2-conferred protection at rates of 5.71%, 2.86%, and 48.57% on the eighth day, respectively. The capacities of these three strains for patulin binding, reduction of C. elegans reproduction toxicity, C. elegans colonization, and C. elegans immune regulation were further evaluated. These three strains showed similar patulin binding abilities at about 30%, while Lactiplantibacillus plantarum subsp. plantarum M2 showed better C. elegans reproduction toxicity detoxification. In addition, only Lactiplantibacillus plantarum subsp. plantarum M2 revealed the ability of colonization in C. elegans and immune regulation. Lactiplantibacillus plantarum subsp. plantarum M2 significantly upregulated the DAF/IGF pathway gene daf-16 and the antitoxin genes sod-3, spp(-1) and lys-7, while mutants that were defective in daf-16 or sod-3 showed no response to protection from Lactiplantibacillus plantarum subsp. plantarum M2. These results suggest that C. elegans can be used to efficiently screen for patulin detoxification strains and the selected strain Lactiplantibacillus plantarum subsp. plantarum M2 shows both patulin binding and C. elegans immune regulation via the DAF/IGF pathway to control the production of superoxide dismutase to combat patulin exposure.