Abstract: Four species of AMF with and without MRE were selected as experimental materials to study the classification status of MRE,the changes of growth index and chlorophyll content of pepper by single spore isolation, molecular biology and in vivo inoculation, in order to preliminarily clarify the potential role and influence of MRE in promoting plant growth and development by AMF.The results showed that MRE belonged to Candidatus Moeniiplasma glomeromycotorum（CaMg）.All the four AMFs could promote the growth of pepper plants, but there were significant differences among different treatments.Compared with blank control, AMF with MRE increased plant height by 11.11%-33.43% and chlorophyll content in pepper leaves by 65.38%-95.19%,AMF without MRE increased plant height by 20.45% and chlorophyll content in pepper leaves by 60.58%.The most significant effect of MRE on plant height and chlorophyll content of capsicum was found in Rc.Compared with Ri without MRE,plant height and chlorophyll content increased by 10.78% and 21.56% after Rc.The potential effect of MRE on the growth of pepper plants by host AMF indicates that MRE is an important potential factor to enhance the promoting effect of host AMF on the growth and development of pepper plants.The results of this study can provide reference for the practice and application of green agriculture by AMF.