PLFA Analysis in Casing Soil of Mushrooms

The analysis of whole-community phospholipid fatty acid (PLFA) profiles has been a useful technique to assess the microbial community structure in soils [1]. PLFA assays are used to determine the fraction of both living fungal and bacterial biomass [2], and it can be also a reliable tool to study the general structure and functionality of microbial communities in mushroom substrate or casing soil, because it describes the response of microbial communities to their immediate environment. In different investigations, PLFA profile showed distinct variation in microbial community biomass and structure depending on the systems studied.

PLFA analysis in Agaricus bisporus

There are few studies in the literature in which PLFA analysis has been used to determine the evolution of microbial community structure during mushroom (Agaricus bisporus) cultivation. In some of these studies, the microbial community structure of casing soil during mushroom growth has been determined [3,4]. In other studies, the PLFA profile of the microbial communities of the substrate used for A. bisporus cultivation has been determined [4, 5, 6, 7]. A comparison of microbial communities and histological changes in Phase I rice straw-based A. bisporus compost prepared using two composting methods has been performed [5]. Other authors compared the microbial communities in rice straw- and wheat straw-based compost for A.bisporus production [6]. Another study assessed the microbiome dynamics in the substrates used for commercial A. bisporus cultivation [4]. Furthermore, the microbial biomass in compost during colonization of A. bisporus was determined using the analysis of PLFAs [7], indicating that A. bisporus suppresses growth of bacteria and impacts the bacterial composition.

In all these studies, changes on the microbial community structure and biomass considering different factors such as substrate composition, phase of mushroom cultivation, composting method, etc. during the assay have been reported. - Maria Sonia Rodriguez Cruz, IRNASA-CSIC.

In addition, other works have studied the evolution of biomass and microbial community structure by means of PLFA analysis in forest soils [8,9], or in a mushroom cultivation substrate different from the one used for A. bispours cultivation, such as oak sawdust [10]. Finally, the analysis of PLFAs profile in soil amended with spent mushroom substrate (SMS) from A. bisporus cultivation to maintain soil quality under laboratory and field conditions has been carried out, where evolution of total bacterial and fungal communities is monitored at different times [11]. Other studies have been carried out to determine the content of microorganisms by PLFA markers during vermicomposting of SMS [10].