Soil Salinity Drives the Distribution Patterns and Ecological Functions of Fungi in Saline-Alkali Land in the Yellow River Delta, China

Abstract

High soil salinity is the main factor that limits soil microbial activity in the Yellow River Delta (YRD); however, its effects on fungal community and ecological function are unknown. Here, we comparatively investigated the diversity and structures of soil fungal communities targeting the internally transcribed fungal spacer gene using Illumina MiSeq sequencing methods under a salt gradient with five levels, namely, Low: low-salinity soil, Medium: medium-salinity soil, High: high-salinity soil, Extreme: extreme-salinity soil, and a non-salted site as the control (Non-saline). The results show that bulk density (BD) values significantly increased (p < 0.05), while significantly lower values of soil total carbon (TC), total nitrogen (TN), and fungal Shannon and Chao indexes were observed as the salinization gradient increased (p < 0.05). The relatively high levels of the families Nectriaceae and Cladosporiaceae distinguished two of the clusters, indicating two enterotypes of low (Non-saline and Low) and high (Medium, High, and Extreme) salinity soils, respectively. The family Nectriaceae was most abundant in the networks, and the positive correlations were more pronounced than negative correlations; however, Cladosporiaceae was the family most negatively correlated with others based on the network analysis. At the ecological function level, plant saprotrophs and litter saprotroph were significantly less abundant in extremely saline soil than non-saline soil. The change in soil properties (TC, TN, and BD) caused by soil salinization [salt and electrical conductivity (EC)] regulated the diversity of soil fungal communities, and ecological function, as indicated by Pearson correlation analyses. We suggest further investigation into the ecological functions of soil microorganisms in the extremely saline-alkaline soils of the YRD.

Inconsistent response of bacterial phyla diversity and abundance to soil salinity in a Chinese delta

“…The soil electrical conductivity value ranged from 0.92 ds/m (CK) to 1.78 ds/m (S1), 3.16 ds/m (S2), 17.26 ds/m (S3), and finally 34.41 ds/m (S4) according to our previous study (Fig. 5 ) 29 .

Figure 5 The salinization degree of sampling sites.

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“…This area has a semi-humid continental climate characterized by a mean annual precipitation and air temperature of 600 mm and 12 °C, respectively. We selected five different salinity levels from low to extreme salinization 29 . In brief, maize croplands with low salinity were selected as the control (CK) and are mainly affected by freshwater flooding.…”

“…The physical and chemical properties and measurement methods of the soil are listed in the Supplementary Materials. Some basic characteristics for the soils in Table S1 were cited from our previous study 29 .…”

Inconsistent Response of Bacterial Phyla Diversity and Abundance to Soil Salinity in A Chinese Delta

“…This area has a semi-humid continental climate characterized by a mean annual precipitation and air temperature of 600 mm and 12°C, respectively. We selected ve different salinity levels from low to extreme salinization 29 . In brief, maize croplands with low salinity were selected as the control (CK) and are mainly affected by freshwater ooding.…”

Fungal Diversity and Composition of the Continental Solar Saltern in Añana Salt Valley (Spain)

“…In the last few years, DNA metabarcoding has become an effective tool for the identification of yeast and other fungal species. Different studies have been conducted on soil, marine, and saline ecosystems; vineyards and wineproduction systems; and in glaciers [16][17][18][19][20][21][22][23], among other ecosystems. Although a study on prokaryotic and virus diversity in the Añana Salt Valley has been published [24], no fungal metabarcoding survey in this ecosystem has been published nor of other continental or inland salterns worldwide.…”