Arbuscular Mycorrhizal Fungal Diversity Associated with Olea europaea L. Growing in Yunnan Province, Southwestern China

Olive(Olea europaea L.)is one of the most important and widely cultivated fruit trees,with high economic,ecological,cultural and scientific value.China began introducing and cultivating olive in the 1960s,and Yunnan Province is one of the main growing areas.Improving the cultivation and productivity of this tree crop species is an important challenge.Olive is a typical mycotrophic species and the potential of arbuscular mycorrhizal fungi(AMF)for this plant is well recognized;nevertheless,studies of olive AMF in China are still very limited.Roots and rhizosphere soils of olive were sampled from five representative growing sites in the Yunnan Province of China to investigate the AMF colonization status in the root systems,the AMF community in the olive orchards and the edaphic factors influencing the arbuscular mycorrhizal(AM)parameters.Root samples of olive trees from different growing sites generally showed AMF colonization,suggesting that autochthonous AMF manifest a high efficiency in colonizing the roots of olive plants.The spore density on the five sites ranged from 81.6 to 350 spores per 20 g soil.Twenty-three AMF species from 9 genera were identified in total,and Glomeraceae was the dominant family.The findings of our study suggested a high AMF diversity harbored by olive growing in different areas of the Yunnan Province,Southwestern China.Furthermore,the hyphal colonization in roots positively correlated with soil pH and EC.The arbuscule colonization in olive roots negatively correlated with soil pH,EC,OM,TN,TP and AN.The spore density positively correlated with OM,TN,AN,AP and sand content.Finally,the Shannon index of AMF in the rhizosphere soil positively correlated with the clay content,but negatively correlated with soil pH,TN and silt content.The high diversity of autochthonous AMF in Yunnan is promising for screening AMF isolates for utilization in the efficient cultivation of this crop.

Arbuscular mycorrhizal fungal community assembly in the Brazilian tropical seasonal dry forest

Introduction:Here,we compare the arbuscular mycorrhizal fungal(AMF)community composition in soils from the root zone of the exotic invasive species Prosopis juliflora(EXO soils)and soils from the root zone of the native species Mimosa tenuiflora(NAT soils)from five locations in the Brazilian tropical seasonal dry forest,Paraíba,Brazil,using morphological analyses.Results:AMF community composition in EXO and NAT soils were dissimilar.Available phosphorus,diversity index,spore abundance,and species richness were the main factors differing between the EXO and NAT soils.In general,the most dominant order present in the soils were Glomerales(44.8%)and Gigasporales(41.4%).The most abundant AMF genus in all studied soils was Funneliformis.Conclusions:Differences in AMF community composition were associated with(1)differences in the dominant plant species(P.juliflora vs.M.tenuiflora)and(2)changes in soil chemical factors(soil,pH,total organic carbon,total nitrogen,and available P)in EXO soils.These results contribute to a deeper view of the AMF communities in exotic soils and open new perspectives for ecological processes involving AMF species and exotic plant species in the Brazilian tropical seasonal dry forest.