Elymus dahucirus is an essential plant for ecological restoration in fragile ecological areas and mining area restoration. As lawn grass, it can quickly cover soil and prevent soil erosion, so it is commonly used as a pioneer grass for lawn greening and slope protection. In recent years, with the development of mineral resources, Qinghai–Tibet Plateau soil is facing the threat of heavy metal cadmium (Cd) pollution. E. dahuricus can host the filamentous fungus Epichloë bromicola. To make better use of the advantages that Epichloë bring to host plants to alleviate heavy metal pollution in soil, plant growth and antioxidant capacity effects on E. bromicola infected (E+) and uninfected (E−) E. dahuricus were determined under Cd stress. During Cd treatment, plant growth was decreased by Cd stress, while E+ plants exhibited equal or better growth compared to E− plants. Cd treatment induces a proline and antioxidant enzyme burst in infected plants, while malondialdehyde (MDA) increases. E. bromicola improved plant growth and antioxidant capacity. E. dahuricus breeding strategies could use the information here in efforts to improve the performance of E. dahuricus in both environmental protection and agronomic contexts.

Strong UV-B radiation is one of the main climatic characteristics of the Qinghai–Tibet Plateau. Plants grown on the Tibetan Plateau are exposed to high-intensity UV radiation and therefore require effective mechanisms to adapt to these stresses. However, little attention has been paid to the response of grass–endophytic fungi symbiosis to UV-B radiation in this area. In this study, we investigated the relationship between Epichloë gansuensis and the growth and antioxidant responses of Achnatherum inebrians seedlings exposed to different UV-B doses, aiming to evaluate the growth and antioxidant capacity of A. inebrians seedlings under UV-B stress. The plant height, tillers, biomass, electrical conductivity, soluble sugars, malondialdehyde (MDA), proline, hydrogen peroxide (H₂O₂), superoxide dismutase (SOD), polyphenol oxidase (POD), and catalase (CAT) of A. inebrians seedlings were determined under different intensities of UV-B radiation treatments. The results showed that, with the increase in UV-B radiation intensity, the plant height, tiller and biomass of A. inebrians seedlings showed a decreasing trend, the electrical conductivity increased, malondialdehyde content increased, soluble sugar and proline content decreased, SOD, POD, and CAT activities showed a decreasing trend, and the content of H₂O₂ increased, which means that the UV-B radiation was able to inhibit the morphogenesis and aggravate the membrane lipid peroxidation of A. inebrians seedlings. The tolerance of the A. inebrians–E. gansuensis symbiont to UV-B may enable it to have a high infection rate on the Qinghai–Tibet Plateau.

Endophytic fungi widely colonize plant tissues without causing severe disease, protect hosts from pathogenic microorganisms, and represent a key potential resource for novel biocontrol agents. To explore the biocontrol potential of endophytic Epichloë fungi and their correlation with alkaloids, 12 Epichloë strains were isolated from six different geographic sites of Festuca sinensis, Achnatherum inebrians, and Hordeum brevisubulatum. The antifungal activity of these strains was evaluated against five phytopathogenic fungi (Alternaria alternata, Bipolaris sorokiniana, Curvularia lunata, Fusarium avenaceum, and Drechslera erythrospila) using dual-culture assays, which measured the inhibition of both colony growth and spore germination. Concurrently, the concentrations of ergonovine and ergine were quantified in the liquid cultures of each Epichloë strain. The results showed that 12 Epichloë strains had varying degrees of inhibitory effects on the colony growth and spore germination of five pathogenic fungi. Among these, strain F2 had the highest inhibition rate on the spore germination of B. sorokiniana (87.73%), while strain H3 had the lowest inhibition rate on F. avenaceum (7.89%). The concentrations of ergonovine and ergine were positively correlated with the inhibition rate of pathogenic fungi, but the degree of these correlations varied among different pathogenic fungi. This study provides further evidence for Epichloë-mediated pathogen inhibition and establishes a basis for their development as biocontrol agents in agricultural systems.

To better understand the mitochondrial genome evolution within the genus Pedicularis, we investigated two representative species, Pedicularis kansuensis and Pedicularis chinensis. We sequenced and assembled the mitochondrial genomes of two Pedicularis species, P. kansuensis and P. chinensis, using Nanopore technology. Both genomes showed irregular morphological characteristics, with P. chinensis measuring 225,612 bp and P. kansuensis 273,598 bp, and GC (guanine and cytosine) contents of 44.42% and 44.29%, respectively. Each genome encodes 36 unique protein-coding genes, 3 rRNA genes, and varying numbers of tRNA genes (P. chinensis: 20; P. kansuensis: 19). Codon usage analysis revealed distinct preferences, while repeat sequence analysis identified significant differences in SSRs, tandem repeats, and dispersed repeats between the two genomes. Structural analyses highlighted genome recombination facilitated by repeat sequences. Phylogenetic analysis confirmed the placement of Pedicularis within Orobanchaceae, clustering P. kansuensis and P. chinensis with Castilleja paramensis and other genera in the family, thus resolving longstanding taxonomic uncertainties regarding their relationship with Scrophulariaceae. RNA editing events were predominantly C-to-U, ccmB and nad4 exhibiting the highest editing frequencies. Synteny analysis revealed frequent rearrangements, underscoring the dynamic evolution of Pedicularis mitochondrial genomes. These findings provide valuable insights into the structure, function, and evolution of mitochondrial genomes in parasitic plants.