Endophytes from blueberry roots and their antifungal activity and plant growth enhancement effects

Abstract: Root endophytic fungi that live with plants in a mutualistic fashion could be promising biological agents to improve biotic resistance and plant growth. In this study, 71 endophytic fungi isolates were obtained from blueberry roots, and they were grouped into 2 phyla, 6 classes, 8 orders, and 16 genera based on characterization of morphological features and variances of ITS1, ITS2, and 5.8s nrDNA sequences. Diaporthe and Fusarium were the most abundant genera. Among them, 16 strains exhibited various levels of antagonicstic abilities against five blueberry pathogens including Botrytis cinerea, Phomopsis sp., Botryosphaeria dothidea, Pestalotiopsis sp., and Fusarium oxysporum. The isolate FLR13, which was classified as Pezicula sp., exhibited the strongest level of antifungal effect (>60%) against these five pathogens and displayed potential biological control effect against Botrytis cinerea in blueberry seedlings. In addition, FLR13 could form typical microsclerotia of dark septate endophyte (DSE) in blueberry root cells to evidently enhance blueberry growth, resulting in the significant increases of 24.13% in height, 88.10% in leaf size, 43.32% in stem diameter, and 54.19% in fresh plant weight as compared with non-FLR13 colonized seedlings. Those results suggest that FLR13 should have potential application in disease control and plant growth enhancement.