Cover cropping can be a stronger determinant than host crop identity for arbuscular mycorrhizal fungal communities colonizing maize and soybean

Abstract

BackgroundUnderstanding the role of communities of arbuscular mycorrhizal fungi (AMF) in agricultural systems is imperative for enhancing crop production. The key variables influencing change in AMF communities are the type of cover crop species or the type of subsequent host crop species. However, how maize and soybean performance is related to the diversity of AMF communities in cover cropping systems remains unclear. We therefore investigated which cover cropping or host identity is the most important factor in shaping AMF community structure in subsequent crop roots using an Illumina Miseq platform amplicon sequencing.MethodsIn this study, we established three cover crop systems (Italian ryegrass, hairy vetch, and brown mustard) or bare fallow prior to planting maize and soybean as cash crops. After cover cropping, we divided the cover crop experimental plots into two subsequent crop plots (maize and soybean) to understand which cover cropping or host crop identity is an important factor for determining the AMF communities and diversity both in maize and soybeans.ResultsWe found that most of the operational taxonomic units (OTUs) in root samples were common in both maize and soybean, and the proportion of common generalists in this experiment for maize and soybean roots was 79.5% according to the multinomial species classification method (CLAM test). The proportion of OTUs specifically detected in only maize and soybean was 9.6% and 10.8%, respectively. Additionally, the cover cropping noticeably altered the AMF community structure in the maize and soybean roots. However, the differentiation of AMF communities between maize and soybean was not significantly different.DiscussionOur results suggest cover cropping prior to planting maize and soybean may be a strong factor for shaping AMF community structure in subsequent maize and soybean roots rather than two host crop identities. Additionally, we could not determine the suitable rotational combination for cover crops and subsequent maize and soybean crops to improve the diversity of the AMF communities in their roots. However, our findings may have implications for understanding suitable rotational combinations between cover crops and subsequent cash crops and further research should investigate in-depth the benefit of AMF on cash crop performances in cover crop rotational systems.

Impact of Phosphorus Fertilization on Tomato Growth and Arbuscular Mycorrhizal Fungal Communities

“…We extracted and prepared a total of 9 genomic DNA samples in this study. We stored the extracted DNA solutions at −30 • C. After DNA extraction, we amplified the partial sequences in the 18S rDNA based on the PCR procedure [43]. A primer pair of NS31 [44] and AM1 [45] was selected for the first step of the PCR to amplify the partial sequences of the 18S rDNA gene for Glomeromycotina [19,20].…”

“…To characterize the AMF community in the tomato roots, we performed high-throughput sequencing of amplicons as described in Higo et al [15,43,48]. Briefly, three PCR products per plot were combined together (from 27 samples to 9 samples) to prepare 9 libraries.…”

“…The analysis of sequences after running the Illumina MiSeq amplicon sequencing was performed according to Higo et al [43]. All sample data after the MiSeq amplicon sequencing were filtered using the FASTX-Toolkit.…”

“…Our findings showed that Glomeraceae, including Glomus, Rhizophagus, and Funneliformis, were the main family in tomato roots, but Gigasporaceae, including Cetraspora, Gigaspora, Racocetra, and Scutellospora, and Acaulosporaceae were also detected in tomato roots (Figure 4 and Figure S2). Previous studies using the Illumina MiSeq Platform have shown that Glomeraceae are predominant in roots and soils [43,48,[72][73][74]. Oehl et al [75], as the result of a pot experiment, reported that Glomeraceae colonize plant roots through pieces of hyphae or colonized roots, thereby quickly constructing hyphal anastomosis [76] and possessing the ability to restore hyphal networks after mechanical disruptions.…”

Slope Position Rather Than Thinning Intensity Affects Arbuscular Mycorrhizal Fungi (AMF) Community in Chinese Fir Plantations

“…Furthermore, AMF play a crucial role in ecosystem sustainability [51,52] by regulating the rhizosphere microbial community composition [53], soil structure, and nutrient cycling [54][55][56]. Given the important role of AMF in individual plants and ecosystem function, several studies have investigated the spore density, root colonization, abundance, and community of AMF using a taxon-based approach [45,[57][58][59]. The majority of these studies, however, have focused on agriculture and grassland systems, and few studies have been undertaken to examine the effects of slope position on AMF spore density, root colonization, and abundance using a taxon-based approach, especially in forests [24,26].…”