The abundance of the endophytic fungi from switchgrass.

The abundance of the endophytic fungi from switchgrass.</p

The distribution of endophytic fungi at species level.

The data were analyzed among different tissues of switchgrass grown on the coal-mining site.</p

The culturable endophytic fungal communities of switchgrass grown on a coal-mining site and their effects on plant growth

<div><p>Plants have a diverse endophytic microbiome that is functionally important for their growth, development, and health. In this study, the diversity and specificity of culturable endophytic fungal communities were explored in one of the most important biofuel crops, switchgrass plants (<i>Panicum virgatum</i> L.), which have been cultivated on a reclaimed coal-mining site for more than 20 years. The endophytic fungi were isolated from the surface-sterilized shoot (leaf and stem), root, and seed tissues of switchgrass plants and then cultured for identification. A total of 1339 fungal isolates were found and 22 operational taxonomic units (OTUs) were sequence identified by internal transcribed spacer (ITS) primers and grouped into 7 orders and 4 classes. Although a diverse range of endophytic fungi associated with switchgrass were documented, the most abundant class, order, and species were Sordariomycetes, Hypocreales, and <i>Fusarium spp</i>. respectively. About 86% of the isolated endophytic fungi were able to enhance the heights of the shoots; 69% could increase the shoot fresh weights; and 62% could improve the shoot dry weights after being reintroduced back into the switchgrass plants, which illustrated their functional importance. Through the Shannon Diversity Index analysis, we observed a gradation of species diversity, with shoots and roots having the similar values and seeds having a lesser value. It was observed that the switchgrass plants showing better growth performance displayed higher endophytic fungal species diversity and abundance. It was also discovered that the rhizosphere soil organic matter content was positively correlated with the fungal species diversity. All these data demonstrate the functional association of these beneficial endophytic fungi with switchgrass and their great potential in improving the switchgrass growth and biomass to benefit the biofuel industry by reducing chemical inputs and burden to the environment.</p></div

The distribution of endophytic fungal isolates from switchgrass.

<p>The isolate numbers (A) and strain types (B) at the order level; and the isolate numbers (C) and strain types (D) at the class level.</p

The distribution of endophytic fungi at species level between two locations on coal-mining site.

<p>The distribution of endophytic fungi at species level between two locations on coal-mining site.</p

The shoot dry weights of the switchgrass plants.

<p>The plants were treated with water control and the water broth containing diverse fungal spores and mycelia at 8 weeks under greenhouse condition. The triangle represents the significant difference existing between the fungal broth treated and water treated plants; the data were further analyzed by the Student’s t-test (P<0.05).</p

Endophytic fungal species abundance among tissues.

<p>Endophytic fungal species abundance among tissues.</p

Shannon indices values and difference analysis of endophytic fungal species diversity.

<p>Shannon indices values and difference analysis of endophytic fungal species diversity.</p

The correlation between Shannon Index value and soil variables.

<p>The correlation between Shannon Index value and soil variables.</p

The levels of pH, organic matter, and major nutrient contents of plant rhizosphere soil.

<p>The levels of pH, organic matter, and major nutrient contents of plant rhizosphere soil.</p