Endophytic fungal diversity and space-time dynamics in sugar beet

We studied species richness, composition and distribution of sugar beet endophytic fungi with location, plant species and plant growth period using the methods of PCR-based 454 pyrosequencing and terminal-restriction fragment length polymorphism. In total 4345 fungal nuclear ribosomal internal transcribed spacer region sequences (rDNA ITS) obtained from all sugar beet grown in two locations (Shihezi and Changji) on the north slope of Tianshan Mountain, China. The most abundant fungal groups in all sugar beet were Basidiomycota (97.26%). The other dominant phyla were from Ascomycota (0.61%) and Glomeromycota (2.13%). There was a marked difference in diversity of endophytic fungi in sugar beet for different growth stages. The greatest number of Operational T-RFLP Units was detected during sucrose accumulation (84) and tuber growth (74). Endophytic fungal diversity was reduced during seedling growth (18 OTUs) and rosette formation (58 OTUs). One OTU was common to all four periods of growth. There were more OTUs in Shihezi than in Changji. The dynamics of endophytic fungal communities were influenced by plant genotype and plant growth stage. Results indicated that the three factors were significantly related (α = 0.05) to the distribution of endophytic fungi, with host species the most important, followed by sampling dates and sampling locations. To our knowledge, this study is the first application of 454 pyrosequencing and T-RFLP to characterize and compare multiple sugar beet samples.