Dynamic succession of substrate-associated bacterial composition and function duringGanoderma lucidumgrowth

Abstract

BackgroundGanoderma lucidum, a valuable medicinal fungus, is widely distributed in China. It grows alongside with a complex microbial ecosystem in the substrate. As sequencing technology advances, it is possible to reveal the composition and functions of substrate-associated bacterial communities.MethodsWe analyzed the bacterial community dynamics in the substrate during the four typical growth stages ofG. lucidumusing next-generation sequencing.ResultsThe physicochemical properties of the substrate (e.g. acidity, moisture, total nitrogen, total phosphorus and total potassium) changed between different growth stages. A total of 598,771 sequences from 12 samples were obtained and assigned to 22 bacterial phyla.ProteobacteriaandFirmicuteswere the dominant phyla. Bacterial community composition and diversity significantly differed between the elongation stage and the other three growth stages. LEfSe analysis revealed a large number of bacterial taxa (e.g.Bacteroidetes,AcidobacteriaandNitrospirae) with significantly higher abundance at the elongation stage. Functional pathway prediction uncovered significant abundance changes of a number of bacterial functional pathways between the elongation stage and other growth stages. At the elongation stage, the abundance of the environmental information processing pathway (mainly membrane transport) decreased, whereas that of the metabolism-related pathways increased.DiscussionThe changes in bacterial community composition, diversity and predicted functions were most likely related to the changes in the moisture and nutrient conditions in the substrate with the growth ofG. lucidum, particularly at the elongation stage. Our findings shed light on theG. lucidum-bacteria-substrate relationships, which should facilitate the industrial cultivation ofG. lucidum.