Effect of exotic Spartina alterniflora on fungal symbiosis with native plants Phragmites australis and Scirpus mariqueter, and model plants Lolium perenne L. and Trifolium repens

• We quantified the incidence of arbuscular mycorrhizal fungi in the Jiuduansha Wetland.
• AMF communities with and without Spartina alterniflora were compared.
• S. alterniflora inhibited AMF colonization and the effect weakened with the invasion age.

The occurrence of arbuscular mycorrhizal fungi (AMF) in wetland after Spartina alterniflora was first introduced into a salt marsh in Shanghai was investigated in this study. Second, a greenhouse experiment was performed to explore the potential effects of S. alterniflora on fungal symbiosis with native Scirpus mariqueter and model plants Lolium perenne L. and Trifolium repens. Field studies showed that the AMF colonization of Phragmite australis grown in mixture communities with P. australis and S. alterniflora was lower than that of single reed communities, suggesting that S. alterniflora inhibited the AMF colonization of reed. In the laboratory, AMF colonization of T. repens and L. perenne L. decreased significantly when S. alterniflora rhizome extracts were added to the plant soils. Moreover, the S. alterniflora communities with less intrusion time showed higher inhibition for AMF colonization. These results have important implications for the restoration of invaded wetlands, suggesting that building and strengthening a mycelium network could contribute to the development of native plant species.