The Effects of Earthworms on Fungal Diversity and Community Structure in Farmland Soil With Returned Straw

Abstract

BackgroundTo promote the decomposition of returned straw, reduce the incidence of soil-borne diseases caused by returned straw, and accelerate the conversion of straw carbon into soil carbon, we inoculated earthworms into fields with returned straw. The earthworms accelerated straw degradation and promoted carbon conversion. However, the impact of externally inoculated earthworms on the farmland soil ecosystem, especially the structure and the function of its microbial community, remains unclear.MethodsWe analyzed the effects of straw return and earthworms on the diversity of fungal populations and the community structure of dominant fungal taxa in soil by quantifying fungal population size and community composition via PCR amplification of internal transcribed spacer genes and 18S rRNA gene sequencing.ResultsThe results showed that earthworm inoculation significantly accelerated the degradation of rice straw and promoted the conversion of straw carbon to soil carbon. Both fungal abundance and α-diversity (Sobs and Shannon indices) were higher in the plots with surface straw but without earthworms than in those inoculated with earthworms and in the CK. Principal component analysis indicated that straw return increased the diversity and the abundance of the fungal community, whereas earthworms inhibited this expansion of the fungal community caused by straw return. Interestingly, the overall differences in fungal community composition were smallest in plots with straw return, while the dominant fungal community features in plots inoculated with earthworms were closer to those of the CK.ConclusionGenerally, straw return stimulated unclassified_K_fungi, Pseudeurotium, and Fusarium with strong cellulolytic ability. In contrast, the abundances of Stachybotrys, unclassified_c_Sordariomycetes, unclassified_f_Lasiosphaeriaceae, and Schizothecium were higher in the plots inoculated with earthworms and in the CK. Furthermore, evolutionary analysis showed that the evolution of soil fungal communities tended to diverge after straw return, and the evolutionary directions of fungal species in the plots inoculated with earthworms were similar to those in the CK.

Animal soil food web complexity triggers shifts in microbial communities, including PAH degraders, but without clear effects on phenanthrene phytoremediation

“…This is in line with previous reports that found that Zopfiella was particularly present during vermicomposting (Neher et al, 2013). In contrast, Zopfiella was found to account for up to 5% of the relative abundance of fungi in control farmland soils, which was significantly higher than in the same soils treated with earthworms (Song et al, 2020). Some Zopfiella species produce zopfiellin, a secondary metabolite with antifungal properties (Futagawa et al, 2002), that could be involved in soil pathogen suppression (Liu et al, 2019) in some soils, and might have indirectly affected the fungal community in our experiment, explaining indirectly some of the SFWC effect on fungal communities.…”

Soil fauna-microbial interactions shifts fungal and bacterial communities under a contamination disturbance

“…Zopfiella was more abundant in our pots containing collembolans and earthworms, in line with its dominance during vermicomposting [ 78 ]. In contrast, Zopfiella was less abundant in the absence of earthworms in a farmland soils [ 79 ]. Some Zopfiella species produce zopfiellin, a secondary metabolite with antifungal properties [ 80 ], that could be involved in soil pathogen suppression [ 81 ], and might have indirectly affected the fungal community in our experiment.…”

Differences in microbial diversity and environmental factors in ploughing-treated tobacco soil

“…Most of the bacteria in this phylum can produce indole acetic acid and ammonia, which can also fix N 2 , all these properties of actinobacteria would promote tobacco growth ( Laassami et al, 2020 ). For the fungal community, unclassified_k_fungi with strong cellulose dissolution ability was present in the samples ( Song et al, 2020 ). As mentioned above, these shared microorganisms in the samples, such as Mortierellomycota, have been reported as effective organic matter transformers ( Santillán et al, 2021 ).…”