Effects of cultivars and habitats on rhizospheric arbuscular mycorrhizal fungal communities associated with Gannan navel oranges

ABSTRACT Rhizospheric arbuscular mycorrhizal fungi (AMF) are vital for the growth of navel oranges (Citrus sinensis Osbeck). However, the molecular diversity of AMF communities associated with navel oranges in the field is largely unknown. This study employed Illumina MiSeq sequencing to reveal the effects of cultivars and habitats on the rhizospheric AMF community. The results showed Glomus and Glomus_sp as the dominant genus (97.0%) and species (22.9%), respectively. The effects of cultivars were higher on rhizospheric AMF diversities and lower on AMF community compositions, when compared with those of habitats. No significant differences in the AMF community diversity and richness were observed between cultivars, whereas the rhizospheric AMF community compositions significantly varied between habitats. The AMF diversity (Shannon and Simpson indices) was negatively correlated with organic matter (OM) content, but positively correlated with available potassium (AK) content (p < 0.05). Both AK and OM were the most important soil factors that affected the AMF community structure. Thus, to regulate the rhizospheric AMF communities of navel oranges, OM inputs should be reduced and K inputs must be increased, which could benefit the functional diversity of AMF.