Transcriptomics-Based Evaluation of the Effects of Polyethylene Microplastics on Pleurotus pulmonarius

Microplastics are widely distributed, but their potential impact on crops cannot be ig-nored. Most current studies focus on common crops such as rice and buckwheat and are mostly at the macro level. In this study, we explored for the first time the changes in agro-nomic traits of <i>Pleurotus pulmonarius</i> by PE-MPs with different concentrations and particle sizes and applied confocal scanning microscopy (CLSM) to observe the uptake of PE-MPs by <i>P. pulmonarius</i> hyphae and combined it with transcriptomics to reveal the stress mech-anism of PE-MPs at the molecular level. Results indicate that among the small-particle groups, only the A5 and A20 groups exhibited significantly lower fresh weight than the CK group. The A5 group was 33.83% lower than the control, while the A20 group was 63.21% lower than CK (<i>p</i> < 0.05). Both the A5 and A20 groups showed significantly lower dry weight than the CK group (<i>p</i> < 0.05). Cap thickness was only greater in the B5 and B10 groups, exceeding the control by 1.46 mm and 1.58 mm, respectively. Cap length was longer only in the A10 group, increasing by 7.85% compared to the control (<i>p</i> < 0.05). Cap width in the A5 and A20 groups was 25.44% and 6.65% lower than the control, respec-tively (<i>p</i> < 0.05). Transcriptomics showed that as the concentration of PE-MPs increased, <i>P. pulmonarius</i> responded to PE-MPs stress by up-regulating the expression of cell membrane composition and metal-ion binding-related genes, while as the particle size increased, <i>P. pulmonarius</i> resisted the toxic effects by up-regulating the coming carbon metabolism and amino acid metabolism. Compared with the CK group, 1706, 1378, and 792 DEGs were identified in the A5, B5, and B10 groups, respectively. A total of 1610 DEGs were identified between the A5 and B5 groups. Additionally, 295 DEGs were identified between the A5 and B10 groups, while 1424 DEGs were identified between the B5 and B10 groups. This study reveals the effects of PE-MPs on the agronomic traits of <i>P. pulmonarius</i> and their re-sponse mechanisms, further indicating their potential risk to edible fungi.