This study investigated ericoid mycorrhizal fungi (EMF) diversity in Vaccinium uliginosum across its main wild distribution range in China. Fungal communities in hair roots of V. uliginosum were analyzed using Illumina MiSeq sequencing. Only 22 OTUs were assigned to putative EMF genera. Rhizoscyphus and Meliniomyces dominated EMF communities, followed by Clavaria, Oidiodendron, Lachnum, Acephala, and Phialocephala. There were more dark septate endophytes (DSE) reads from the Greater Khingan Mountains than from other study areas, similar to the results of the percent colonization of DSE by the magnified intersections method. Overall, high-throughput sequencing data provided a rough community-scale sketch of root-associated fungi of V. uliginosum. Two hundred and eighty slow-growing isolates were isolated from root pieces of V. uliginosum, and the isolates matched 16 fungal genera on the basis of morphological and internal transcribed spacer sequence comparison. The isolates of Cryptosporiopsis ericae, Oidiodendron maius, Lachnum sp., Sordariomycetes sp., and Pleosporales sp., formed ericoid hyphal coils via resynthesis trails. The co-existence between EMF and DSE in hair roots was observed via trypan blue staining. A putative model for the co-existence between EMF and DSE in the hair roots of V. uliginosum was proposed. We suggest that under certain environmental stresses, such as low temperature and poor available nutrients, ericoid plants may favor co-colonization by both DSE and EMF.

MicroRNAs (miRNAs) are a class of small endogenous RNAs that play important regulatory roles in plants by negatively affecting gene expression. Studies on the identification of miRNAs and their functions in various plant species and organs have significantly contributed to plant development research. In the current study, we utilized high-throughput sequencing to detect the miRNAs in the root, stem, and leaf tissues of raspberry (Rubus idaeus). A total of more than 35 million small RNA reads ranging in size from 18 to 35 nucleotides were obtained, with 147 known miRNAs and 542 novel miRNAs identified among the three organs. Sequence verification and the relative expression profiles of the six known miRNAs were investigated by stem-loop quantitative real-time PCR. Furthermore, the potential target genes of the known and novel miRNAs were predicted and subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway annotation. Enrichment analysis of the GO-associated biological processes and molecular functions revealed that these target genes were potentially involved in a wide range of metabolic pathways and developmental processes. Moreover, the miRNA target prediction revealed that most of the targets predicted as transcription factor-coding genes are involved in cellular and metabolic processes. This report is the first to identify miRNAs in raspberry. The detected miRNAs were analyzed by cluster analysis according to their expression, which revealed that these conservative miRNAs are necessary for plant functioning. The results add novel miRNAs to the raspberry transcriptome, providing a useful resource for the further elucidation of the functional roles of miRNAs in raspberry growth and development.

Background: Ericoid mycorrhizal fungi (EMF) play important roles in mineral cycling and plant nutrient acquisition, and they increase plant survival in nutrient-poor environments. In this study, we detected the colonization of EMF using a green fluorescent protein (GFP) expression method and in situ PCR. Results: Genetic transformants of Cryptosporiopsis ericae and Sordariomycetes sp. expressing GFP were obtained via Agrobacterium tumefaciens-mediated transformation. GFP transformants were able to infect Vaccinium uliginosum, and their fluorescence was visible in the hair roots. Both in situ PCR and the GFP-expressing method indicated that EMF could colonize the hair roots of V. uliginosum 2 weeks after inoculation. Conclusions: This research represents the first attempt to detect ericoid mycorrhizal colonization using in situ PCR. A GFP-expressing method is an excellent system for detecting the colonization of EMF, but it is dependent on the successful transformation and expression of the gfp gene. In situ PCR and the GFP expression may be developed as new tools to study the interactions of EMF both with ericaceous plants and with the environment.

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