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Summary: Elucidating the temporal dynamics of arbuscular mycorrhizal (AM) fungi is critical for understanding their functions. Furthermore, research investigating the temporal dynamics of AM fungi in response to agricultural practices remains in its infancy.We investigated the effect of nitrogen fertilisation and watering reduction on the temporal dynamics of AM fungi, across the lifespan of wheat.Nitrogen fertilisation decreased AM fungal spore density (SD), extraradical hyphal density (ERHD), and intraradical colonisation rate (IRCR) in both watering conditions. Nitrogen fertilisation affected AM fungal community composition in soil but not in roots, regardless of watering conditions. The temporal analysis revealed that AM fungal ERHD and IRCR were higher under conventional watering and lower under reduced watering in March than in other growth stages at low (≤ 70 kg N ha−1 yr−1) but not at high (≥ 140) nitrogen fertilisation levels. AM fungal SD was lower in June than in other growth stages and community composition varied with plant development at all nitrogen fertilisation levels, regardless of watering conditions.This study demonstrates that high nitrogen fertilisation levels disrupt the temporal dynamics of AM fungal hyphal growth but not sporulation and community composition. [ABSTRACT FROM AUTHOR]

Soil arbuscular mycorrhizal (AM) fungi were monitored in a 4-year experiment of nitrogen (N) and phosphorus (P) fertilization in three growing seasons (April, August, and November) under two successional stages (young and mature) in a subtropical forest of China. AM fungal extra-radical hyphal density was significantly affected by fertilization, season, and interactions between fertilization and season and between forest stage and season, but not by forest stage. The spore density of AM fungi was significantly affected by forest stage and season, but not by fertilization. Totally, 160 operational taxonomic units (OTUs) of AM fungi have been identified at a 97% sequence similarity level using Illumina MiSeq sequencing of the V4 region of the 18S rDNA. AM fungal Shannon diversity index, but not OTU richness, showed a positive response to P fertilization. The community composition of AM fungi was significantly influenced by P fertilization, but not by N fertilization, season, and forest stage. Phosphorus fertilization exhibited a negative impact on the relative abundance of the dominant Glomeraceae. This finding highlights that P availability has a strong effect on the community of AM fungi in the subtropical forest ecosystem. [ABSTRACT FROM AUTHOR]

Elucidating symbiotic relationships between arbuscular mycorrhizal fungi (AMF) and plants contributes to a better understanding of their reciprocally dependent coexistence and community assembly. However, the main drivers of plant and AMF community assembly remain unclear. In this study, we examined AMF communities from 166 root samples of 17 woody plant species from 10 quadrats in a Chinese subtropical forest using 454 pyrosequencing of 18S rRNA gene to describe symbiotic AMF–plant association. Our results show the woody plant–AMF networks to be highly interconnected and nested, but in antimodular and antispecialized manners. The nonrandom pattern in the woody plant–AMF network was explained by plant and AMF phylogenies, with a tendency for a stronger phylogenetic signal by plant than AMF phylogeny. This study suggests that the phylogenetic niche conservatism in woody plants and their AMF symbionts could contribute to interdependent AMF and plant community assembly in this subtropical forest ecosystem. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal (AM) fungi play key roles in plant nutrition and plant productivity. AM fungal responses to either plant identity or fertilization have been investigated. However, the interactive effects of different plant species and fertilizer types on these symbiotic fungi remain poorly understood. We evaluated the effects of the factorial combinations of plant identity (grasses Avena sativa and Elymus nutans and legume Vicia sativa) and fertilization (urea and sheep manure) on AM fungi following 2-year monocultures in a sown pasture field study. AM fungal extraradical hyphal density was significantly higher in E. nutans than that in A. sativa and V. sativa in the unfertilized control and was significantly increased by urea and manure in A. sativa and by manure only in E. nutans, but not by either fertilizers in V. sativa. AM fungal spore density was not significantly affected by plant identity or fertilization. Forty-eight operational taxonomic units (OTUs) of AM fungi were obtained through 454 pyrosequencing of 18S rDNA. The OTU richness and Shannon diversity index of AM fungi were significantly higher in E. nutans than those in V. sativa and/or A. sativa, but not significantly affected by any fertilizer in all of the three plant species. AM fungal community composition was significantly structured directly by plant identity only and indirectly by both urea addition and plant identity through soil total nitrogen content. Our findings highlight that plant identity has stronger influence than fertilization on belowground AM fungal community in this converted pastureland from an alpine meadow. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal (AM) fungi form mutualistic symbioses with most plant species and play important roles in ecosystems. Knowledge of the response of AM fungi to temperature change will improve our understanding of the function of AM fungal community under global climate change scenarios in ecosystems. The effects of constant warming on AM fungal communities have been investigated previously, but responses to asymmetrical warming over 24-h periods have never been documented in natural ecosystems. In this study, we examined AM fungal communities in a full factorial design including day-time and night-time warming in a semiarid steppe in northern China. Day-time and 24-h warming, but not night-time warming, significantly increased AM fungal spore density. In contrast, none of the three warming regimes had a significant effect on AM fungal extra radical hyphal density. A total of 161 operational taxonomic units (OTUs) of AM fungi were recovered by 454 pyrosequencing of 18S rDNA. Day-time, night-time, and 24-h warming all significantly increased AM fungal OTU richness. Some AM fungal OTUs showed a significant bias toward day-time, night-time or 24-h warming. The AM fungal community composition was significantly affected by night-time warming, but not by day-time and 24-h warming. Our finding highlighted different responses of AM fungal spore density and community composition to asymmetrical warming. This study might improve our understanding of ecosystem functioning of AM fungal community under global climate change scenarios in a semiarid steppe ecosystem. [ABSTRACT FROM AUTHOR]

Elucidating the responses of soil microbial abundance and community composition to nitrogen (N) addition is important for predicting ecosystem function under increased atmospheric N deposition. We examined the arbuscular mycorrhizal ( AM) fungal community under three N forms ( [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal (AM) fungus community composition and diversity among the forest, grassland, and cropland ecosystems in the Tibetan Plateau were carried out in this study. A total of 44 AM fungi belonging to six genera were isolated from 144 soil samples collected from forest, grassland, and cropland. Of these AM fungi, 40 taxa were found in forest, 19 in grassland, and 19 in cropland. Glomus was the dominant genus in the three ecosystems, as well as Acaulospora was dominant in forest and grassland. Acaulospora laevis and A. scrobiculata were the dominant species in forest. Acaulospora laevis and Glomus mosseae were dominant in grassland and cropland. The spore density, species richness, and Shannon diversity index of AM fungi from high to low were forest > grassland > cropland. The Sorenson's similarity coefficients of AM fungus community composition ranged from 0.58 to 0.63 between the forest, grassland, and cropland. The results revealed that there was high diversity of AM fungi and the AM fungal community composition varied among the three ecosystems. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal (AM) fungi form symbiotic associations with most plant species in terrestrial ecosystems, and are affected by environmental variations. To reveal the impact of disturbance on an AM fungal community under future global warming, we examined the abundance and community composition of AM fungi in both soil and mixed roots in an alpine meadow on the Qinghai-Tibetan Plateau, China. Warming and grazing had no significant effect on AM root colonization, spore density and extraradical hyphal density. A total of 65 operational taxonomic units (OTUs) of AM fungi were identified from soil and roots using molecular techniques. AM fungal OTU richness was higher in soil (54 OTUs) than in roots (34 OTUs), and some AM fungi that differed between soil and roots, showed significantly biased occurrence to warming or grazing. Warming and grazing did not significantly affect AM fungal OTU richness in soil, but warming with grazing significantly increased AM fungal OTU richness in roots compared to the grazing-only treatment. Non-metric multidimensional scaling analysis showed that the AM fungal community composition was significantly different between soil and roots, and was significantly affected by grazing in roots, whereas in soil it was significantly affected by warming and plant species richness. The results suggest that the AM fungal community responds differently to warming and grazing in soil compared with roots. This study provides insights into the role of AM fungi under global environmental change scenarios in alpine meadows of the Qinghai-Tibetan Plateau. [ABSTRACT FROM AUTHOR]

• AM fungal spore density was influenced by growth phase and fertilization. • AM fungal extra-radical hyphal density was affected by growth phase and irrigation. • AM fungal root colonization rate was affected by growth phase, irrigation and fertilization. • Irrigation affected AM fungal richness in soil and roots. • Growth phase influenced AM fungal community composition in soil and roots. Arbuscular mycorrhizal (AM) fungi form mutualistic associations with most terrestrial plants and can enhance crop water and nutrition acquisition. It is thus important to elucidate the interactive impacts of water and fertilizer management on AM fungi for sustainable agriculture. Our study investigated the effects of irrigation (well-watered vs. drought) and fertilization (nitrogen (N), phosphorus (P), and NP) on AM fungi in soil and roots of maize (Zea mays L.) across three consecutive growth phases (jointing, tasseling, and mature). Drought significantly decreased AM fungal extra-radical hyphal density and root colonization rate at the tasseling and mature phases, respectively. Nitrogen and NP fertilization exerted a negative effect on AM fungal spore density under drought at the mature phase. Drought decreased AM fungal richness in soil and roots at the jointing and mature phases, respectively. AM fungal community composition in soil and roots was significantly different between the jointing phase and the tasseling and mature phases. AM fungal community composition was influenced by fertilization at the tasseling phase in soil, but by irrigation at the jointing and tasseling phases in roots. Our findings highlight the differential response of AM fungi in soil and roots to drought and fertilization during the various phases of maize development in this dryland agroecosystem. [ABSTRACT FROM AUTHOR]