Molecular diversity and distribution of arbuscular mycorrhizal fungi in karst ecosystem, Southwest China

摘要

Nested polymerase chain reaction and denaturing gradient gel electrophoresis (DGGE) was used to study the molecular diverstiy and distribution of arbuscular mycorrhizal fungi (AMF) from microhabitats of three different vegetation types in karst ecosystem, Southwest China. We found molecular diversity in all three microhabitat types was high. The highest values of biodiversity index (4.06) and species abundance (68) were found in the shrubland soil surface, and the lowest values (3.16 and 29, respectively) were found in the secondary forest rocky crevice. The average values of biodiversity index and species abundance of the nine microhabitats studied were 3.67 and 48, respectively. The index value was higher than those in other areas of China; the possible reason might be the intricate karst ecological system structure, diverse plant species and a long-term mutual adaptation process. The AMF molecular diversity of different microhabitat types showed significant differences. The highest similarity index was only 0.45, which means the spatial heterogeneity of microhabitat types had significant influence on AMF molecular diversity. Glomus was the dominant genus in the karst area and should be a candidate for ecological restoration in karst areas. All together, our research provided an empirical, scientific basis for rational exploitation of AMF in karst ecosytem and rocky desertification restoration.