Powdery mildew (PM) is one of the most devastating and wide spread fungal diseases of rose, which seriously decrease its productivity and commercial value. In the present study, the endophytic fungal communities of two wild Rosa varieties (Rosa multiflora Thunb and R. multiflora var. carnea Redouté and Thory) with different PM susceptibilities were studied through Illumina MiSeq sequencer. A total of 14,000,424 raw reads were obtained from 60 samples, and 6,862,953 tags were produced after merging paired-end reads. 4462 distinct OTUs were generated at a 97% similarity level. It was found that only 34.2% of OTUs shared between two plant varieties. All of the OTUs were assigned into four fungal phyla, 17 classes, 43 orders, 86 families, 157 genera, and 208 species. Members of Ascomycota were found to be the most common fungal endophytes (EF) among all plant samples (93.7% relative abundance), followed by Basidiomycota (4.7% relative abundance), while Zygomycota and Glomeromycota were found to be rare and incidental. At each developmental stage of plants, the diversity and community structure of EF between two Rosa varieties showed significant differences. Both PCoA plots and PERMANOVA analyses indicated that developmental stage was the major factor contributing to the difference between the Rosa varieties (R2 = 0.348, p < 0.001). In addition, plant varieties and tissues were also important factors contributing to the difference (R2 = 0.031, p < 0.05; R2 = 0.029, p < 0.05). Moreover, Neofusicoccum, Rhodosporidium, and Podosphaera, etc., were found to be significantly different between two Rosa varieties, and some of the endophytes may play a role in PM resistance. These finding are encouraging to testify the potential use of these fungi in the biocontrol of PM in future studies.

H igh concentration of h eavy metal (HM) is toxic to the plant and endophytes can improve host plants HM tolerance. In the present study, the role of endophytes FT2G7 (Phomopsis columnaris) and FT2G24 (Setophoma terrestris) on host plant Dysphania ambrosioides HM tolerance was evaluated under m ulti-HMs stress through pot experiments. The results showed that regardless at lower or higher multi-HMs stress, inoculation of isolate(s) improved host plants growth and HM tolerance through regulating their antioxidant capacities etc., and inoculation of multi-isolates (ME+) had better effects on host plants than inoculation of single isolate (SE+). Particularly, the malondialdehyde (MDA) of ME+ decreased 50% under the lower multi-HMs stress and the glutathione (GSH) increased 169.55% under the higher multi-HMs stress when compared with ME-. Both inoculation of single isolate and multi-isolates increased host plants HM accumulation when compared with non-inoculation. However, different isolates had different effects: under the lower multi-HMs stress, the accumulation of multi-HMs in ME+ plants was higher than that of FT2G7-inoculated plants but lower than that of F T2G24-inoculated plants, w ith a few e xceptions, such as Zn in underground parts of ME+ was higher than that of FT2G24-inoculated plants. The bioaccumulation factor (BAF) of ME+ was higher than that of SE+, but the translocation factor (TF) was lower than that of SE+, e xcept Pb of FT2G24 inoculated plants. Under the higher multi-HMs stress, Zn and Cd in ME+ plants were lower but Pb was higher than that of SE+, with a few exceptions, such as Pb in underground parts of ME+ plants was lower than that of FT2G24-inoculated plants. The BAF and TF of ME+ were lower than that of SE+, except that of Pb.

No abstract