Endorhizal fungal symbiosis in lycophytes and metal(loid)-accumulating ferns growing naturally in mine wastes in Mexico

Ferns and lycophytes are pioneer plants that can be useful for revegetation. Their natural distribution and interaction with soil fungal endophytes can increase plant fitness but have received little attention. This study aimed to identify these plant species in mine wastes, and determine colonization by arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE). The pseudo-total and diethylenetriamine pentaacetic acid (DTPA)-extractable rhizosphere concentrations of As, Cu, Cd, Pb, and Zn, bioavailability index (BI), and bioconcentration factor (BCF) were analyzed. Six ferns and one lycophyte were identified. Arsenic and metal concentrations were high, which were plant and site-dependent. All species showed hyperaccumulation of As in fronds, especially <i>Argyrochosma formosa</i> (2,883) and <i>Notholaena affinis</i> (2,160) had the highest concentrations (mg kg⁻¹). All plants were colonized by AMF (3%−24%) and DSE (2%−33%). <i>Astrolepis sinuata</i> and <i>Myriopteris notholaenoides</i> had the maximum colonization by AMF and <i>A. formosa</i> by DSE. This study identifies for the first time five ferns and one lycophyte species on mine wastes, their As hyperaccumulation capacity and the simultaneous fungal colonization by AMF and DSE. These are relevant plant traits for phytoremediation. However, fungal identification and the role colonization by AMF and DSE requires full analysis. Arsenic accumulator ferns and a lycophytes species naturally established on three polluted sites were found. <i>Astrolepis integerrima, A. sinuata</i>, <i>Myriopteris notholaenoides, Notholaena affinis</i>, <i>N. sulphurea</i>, and the lycophyte <i>Selaginella lepidophylla</i> are for the first time reported in these sites. This is the first evidence of DSE colonization in these plants growing on mine wastes in interaction with AMF-colonization. These plants may be useful in developing phytoremediation alternatives.