Abstract: The present disclosure provides a Brevundimonas strain as an endosymbiont of Verticillium dahliae, which is named Brevundimonas olei dahliae olei (B. olei) and deposited with the accession number of CCTCC NO: M 2020392. Morphological identification and diversity sequencing analysis confirm that the symbiont is B. olei. The effect of B. olei fermentation broth on growth and microsclerotia of Verticillium dahliae is explored through a co-cultivation experiment. Observations through electron microscope find that, with the increase of culture time and fermentation broth concentration, the Verticillium dahliae forms fewer conidia, its hyphae swell, rupture, and become abnormal in shape, and its microsclerotia gradually decrease and even disappear.

Abstract: A method for producing an organic fertilizer enabling an increased microbial diversity and abundance in soil, and use of the organic fertilizer are provided. The method comprises composting fresh S. alopecuroides plants together with sheep and/or goat manure through anaerobic fermentation. It is found through experiments that, by applying the organic fertilizer produced by the method to a soil in which melon plants are grown, both abundance of bacterial and fungal communities in the rhizosphere of the plants and contents of soluble solids and sugar in fruit of the plants are increased. By a combination of taxonomic composition of the microbial communities in the rhizosphere and RDA analysis, it is further found that abundance of multiple bacterial and fungal species conducive to growth and disease resistance of the plants, is substantially increased and positively correlated with the soluble solids and sugar contents in the fruit.