Impact of Vegetation Restoration on Soil Fungal Community Structure in Karst Rocky Desertification Areas

In this paper,managed forest(MF)and natural forest(NF)in the Huajiang Demonstration Zone of Guanling,Guizhou were selected as research objects,and cropland(CL)was taken as control.High-throughput sequencing technology was used to study the characteristics of fungal community composition and species diversity in the surface(0-10 cm)soil of each restoration measure,in order to reveal the dominant soil fungal groups and fungal community composition in karst rocky desertification areas,which was conducive to a more comprehensive understanding of the soil conditions of different vegetation restoration measures.Research has shown that vegetation restoration significantly affected the diversity of soil fungal community,with significant increases in Sob index,Ace index,and Chao index.The vegetation restoration has significantly changed the composition of fungal community.The dominant fungi in the CL topsoil are Sordariomycetes(62.28%),Dothideomycetes(12.34%),and Eurotiomycetes(9.12%);the dominant fungi in the MF soil are Sordariomycetes(45.05%),Dothideomycetes(14.74%),and Mortierellomycetes(10.40%);the dominant fungi in the NF soil are unclassified fungal community(26.38%),Sordariomycetes(19.78%),and Agaricomycetes(13.82%).Vegetation restoration has changed the key fungal groups in the soil.Sordariomycetes,Fusarium,and Setophoma are the key dominant fungal groups in CL soil;Dioszegia is key dominant fungal group in MF soil;c_unclassified_k_Fungi,p_unclassified_k_Fungi,o_unclassified_k_Fungi,f_unclassified_k_Fungi,g_unclassified_k_Fungi,Teichospora,and Diaporthe are key dominant fungal groups in NF soil.

Contrasting soil fungal communities in Mediterranean pine forests subjected to different wildfire frequencies

Mediterranean forest ecosystems are characterized by various vascular plant groups with their associated mycor-rhizae and free living soil fungi with various ecological functions.Fire plays a major role in Mediterranean ecosystem dynamics and impacts both above-and below-ground community structure and functioning.However,studies on the effects induced by altered disturbance regimes(associated with recent land use and climate extremes)on fire ecology and especially on its below-ground impacts are few.The objectives of this study were to evaluate the effects of different wildfire regimes on soil fungal community structure using two different molecular methods.We investigated the long-term effects of wildfire on soil fungal communities associated with Pinus pinaster forests in central Portugal,by comparing the results of denaturing gradient gel electrophoresis(DGGE)-based profiling with those obtained with 454 pyrosequencing.Four forest stands with differing fire history and fire return interval,and vegetation cover(mature forest,early successional stage of pine regeneration,and forest converted to scrubland)were sampled 6 years after the last fire event.The pyrosequencing-based approach indicated ca.eight-fold higher numbers of taxa than DGGE.However,fungal community fingerprinting data obtained for the different study stands with DGGE were congruent with those obtained with pyrosequencing.Both short(7.6 years)and long(24 years)fire return intervals(indicated by the presence of ericaceous shrubs in the understorey)induced a decrease in the abun-dance ratio between basidiomycetes and ascomycetes and appeared to reduce the frequency of ectomycorrhizal fungal species and saprophytes.Wildfire significantly reduced the frequency of late stage successional taxa(e.g.Atheliaceae and Cantharellales)and known or putative saprophytes belonging to the Clavulinaceae and the Archaeorhizomycetaceae.Conversely,early successional fungal species belonging to the Thelephoraceae were favoured by both fire return inter-vals,while the abundance of Cortinarius and Hebeloma,which include several Cistus-specific species,increased with short wildfire return intervals.This last finding highlights the relationship between postfire vegetation composition and cover(vegetation successional stage),and fungal symbionts.We hypothesise that these changes could,in the long term,exhaust the resilience of Mediterranean pine forest vegetation and associated soil fungal communities by preventing pine regeneration.

Soil Fungal Diversity and Community Composition in Response to Continuous Sweet Potato Cropping Practices

Soil fungi are extremely important for maintaining soil health and plant production in agricultural systems.Currently,the effect of continuous cropping of sweet potato on soil fungal communities and physiochemical parameters has not been well documented.In the present study,four sweet potato fields consecutively monocultured for 1,2,3,and 4 years were selected to investigate the effect of monoculture on soil fungal communities through Illumina MiSeq sequencing.Continuous cropping of sweet potatoes dramatically altered the fungal community composition,whereas fungal diversity was almost unchanged.Ascomycota and Basidiomycota were the most abundant phyla in all soil samples,accounting for 32.59%and 21.14%of the average relative abundance,respectively.The abundance of some potential pathogens,such as Ascobolus spp,specifically Ascobolus stercorarius,and some unknown fungi increased significantly as the sweet potato monoculture period increased,and their presence were highly positively correlated with disease incidence.In contrast,Basidiomycota,Bullera,Fusarium and Trichocladium most likely play roles as antagonists of sweet potato disease development,as their relative abundance decreased significantly over time and were negatively correlated with disease incidence.Redundancy and correlation analyses revealed that soil pH and organic carbon content were the most important factors driving these changes.Our findings provided a dynamic overview of the fungal community and presented a clear scope for screening beneficial fungi and pathogens of sweet potato.

Spore production in the solid-state fermentation of stevia residue by Trichoderma guizhouense and its effects on corn growth

Trichoderma is an important and widely used plant growth-promoting fungus(PGPF).In this study,stevia residue amended with amino acids hydrolyzed from animal carcasses was used for the production of Trichoderma guizhouense NJAU 4742 by solid-state fermentation,and then its potential to promote corn plant growth was evaluated in combination with chemical fertilizer(CF)or organic fertilizer(OF).The highest spore number of 7×10^(9) CFU g^(–1) fresh weight was obtained under the following optimal parameters:material ratio of 50%(stevia residue:rice bran=1:1),pH value of 3.0(amended with 6.67%amino acids),initial moisture content of 60%,inoculum size of 10%,material thickness of 3 cm and an incubation time of 4 days.The aboveground corn plant biomass obtained with T.guizhouense applied alone and with CF treatments were slightly higher than those of no fertilizer control and CF treatments,respectively.However,T.guizhouense applied with OF significantly(P<0.05)increased aboveground biomass compared to OF and yielded the highest aboveground biomass among all the treatments.Moreover,T.guizhouense applications primarily influenced the fungal bulk soil community composition,among which three OTUs(OTU_(2) and OTU_(9) classified as Chaetomium,and OTU_(4)classified as Trichoderma)were stimulated in both bulk and rhizosphere soil.Notably,a specific OTU_(3)(Phymatotrichopsis)was only stimulated by T.guizhouense applied with OF,possibly leading to high soil productivity.These results show that it is feasible to employ stevia residue in the eco-friendly fermentation of T.guizhouense,which is strongly suggested for enhancing OF applications.

Subsurface aeration alters the fungal composition of rhizosphere soil and tomato plant performance in Northwest China

Rhizosphere hypoxia constrains plant growth,and numerous studies have shown that root zone aeration accelerates plant photosynthesis and growth and increases crop yields.Nevertheless,the mechanism by which soil microorganisms are involved in this process is not clear.The purpose of the present study was to examine the effects of aeration and irrigation depth on the composition and structure of rhizosphere soil fungal communities and tomato plant performance.The amount of aeration assayed was equal to 0(CK),0.5(V1),1(V2),and 1.5(V3)times the porosity of the soil.The two depths of subsurface drip irrigation used were 15(D15)and 40 cm(D40).The results demonstrated that soil aeration not only increased tomato plant performance but also influenced fungal diversity and composition.Compared to the no-aeration treatment,the V3 soil aeration treatment increased the total dry weight and fruit yield by 39.9%and 65.6%,respectively.The results also showed that the abundance of the phylum Ascomycota and the family Lasiosphaeriaceae increased with increasing soil aeration,whereas those of members of the phylum Zygomycota and the order Capnodiales decreased with increasing soil aeration.Moreover,the variation in subsurface irrigation depth altered the rhizosphere soil fungal community.In general,the results of this study demonstrate that root zone aeration can ameliorate hypoxic conditions in Lou soils and is beneficial to soil fungal communities and tomato plant performance.