Sebacinales, but not total root associated fungal communities, are affected by land-use intensity.

Abstract

There is great scientific and societal interest in the ecology and functioning of the immense diversity of microorganisms associated with plant roots (Mendes et al., 2011; Porras-Alfaro & Bayman, 2011). In particular, research into plant–soil interactions has unveiled a pivotal role of root-associated fungi in influencing plant growth and community structure (van der Heijden et al., 2008; Schnitzer et al., 2011; Wagg et al., 2014). So far, knowledge on the identity of fungi associated with plant roots, and forces structuring the communities they form, is still scarce. This extends to agricultural systems, where communities of belowground fungi are a largely unknown but potentially important driver of plant productivity akin to natural systems, and display a considerably high diversity (Orgiazzi et al., 2012). So far, most research has focused on plant pathogens (e.g.Xu et al., 2012) and on arbuscularmycorrhizal fungi (AMF). AMF are an important group of plant symbionts, and we know that these generally increase in diversity in response to reduced agricultural management intensity (Oehl et al., 2004; Verbruggen et al., 2012). For other groups of root endophytes little is known about responses to agricultural management, even though they may be of high ecological significance (Rodriguez et al., 2009). Apart from potential effects on plants, there is great interest in identifying taxa that may serve as bio-markers for sustainable agricultural practices, as has recently been explored for AMF by Jansa et al. (2014). So far this has not been attempted for other root inhabiting fungi, likely because it is unknown whether root-colonizing fungi are sensitive to changes in land-use intensity. In this study we have sampled wheat roots in agricultural fields that were either managed conventionally (seven sites) or had been converted to organic farming recently (2–4 yr; eight sites), moderately long ago (10– 14 yr; six sites), or had been subjected to long-term organic farming (16–33 yr; eight sites). We analyzed the fungal community in roots using next generation sequencing of fungi and ask how different biotic and abiotic aspects drive fungal communities inhabiting wheat roots.