Plant and fungal species interactions differ between aboveground and belowground habitats in mountain forests of eastern China

Plant and fungal species interactions drive many essential ecosystem properties and processes;however,how these interactions differ between aboveground and belowground habitats remains unclear at large spatial scales.Here,we surveyed 494 pairwise fungal communities in leaves and soils by Illumina sequencing,which were associated with 55 woody plant species across more than 2,000-km span of mountain forests in eastern China.The relative contributions of plant,climate,soil and space to the variation of fungal communities were assessed,and the plant-fungus network topologies were inferred.Plant phylogeny was the strongest predictor for fungal community composition in leaves,accounting for 19.1%of the variation.In soils,plant phylogeny,climatic factors and soil properties explained 9.2%,9.0%and 8.7%of the variation in soil fungal community,respectively.The plant-fungus networks in leaves exhibited significantly higher specialization,modularity and robustness(resistance to node loss),but less complicated topology(e.g.,significantly lower linkage density and mean number of links)than those in soils.In addition,host/fungus preference combinations and key species,such as hubs and connectors,in bipartite networks differed strikingly between aboveground and belowground samples.The findings provide novel insights into cross-kingdom(plant-fungus)species co-occurrence at large spatial scales.The data further suggest that community shifts of trees due to climate change or human activities will impair aboveground and belowground forest fungal diversity in different ways.

Nitric Oxide and Brassinosteroids Mediated Fungal Endophyte-Induced Volatile Oil Production Through Protein Phosphorylation Pathways in Atractylodes lancea Plantlets

Fungal endophytes have been isolated from almost every plant, infecting their hosts without causing visible disease symptoms, and yet have still proved to be involved in plant secondary metabolites accumulation. To decipher the possible physiological mechanisms of the endophytic fungus-host interaction, the role of protein phosphorylation and the relationship between endophytic fungus-induced kinase activity and nitric oxide （NO） and brassinolide （BL） in endophyte-enhanced volatile oil accumulation in Atractylodes lancea plantlets were investigated using pharmacological and biochemical approaches. Inoculation with the endophytic fungus Gilmaniella sp. ALl2 enhanced the activities of total protein phosphorylation, Ca2^-dependent protein kinase, and volatile oil accumulation in A. lancea plantlets. The upregulation of protein kinase activity could be blocked by the BL inhibitor brassinazole. Furthermore, pretreatments with the NO-specific scavenger cPTIO significantly reduced the increased activities of protein kinases in A. lancea plantlets inoculated with endophytic fungus. Pretreatments with different protein kinase inhibitors also reduced fungus-induced NO production and volatile oil accumulation, but had barely no effect on the BL level. These data suggest that protein phosphorylation is required for endophyte- induced volatile oil production in A. lancea plantlets, and that crosstalk between protein phosphorylation and the NO pathway may occur and act as a downstream signaling event of the BL pathway.