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Salt stress negatively affects plant growth, and the fungal endophyte Epichloëgansuensisincreases the tolerance of its host grass species, Achnatherum inebrians, to abiotic stresses. In this work, we first evaluated the effects of E. gansuensison glucose-6-phosphate dehydrogenase (G6PDH) and plasma membrane (PM) H+-ATPase activity of Achnatherum inebriansplants under varying NaCl concentrations. Our results showed that the presence of E. gansuensisincreased G6PDH, PM H+-ATPase, superoxide dismutase and catalase activity to decrease O2•−, H2O2and Na+contents in A. inebriansunder NaCl stress, resulting in enhanced salt tolerance. In addition, the PM NADPH oxidase activity and NADPH/NADP+ratios were all lower in A. inebrianswith E. ganusensisplants than A. inebriansplants without this endophyte under NaCl stress. In conclusion, E. gansuensishas a positive role in improving host grass yield under NaCl stress by enhancing the activity of G6PDH and PM H+-ATPase to decrease ROS content. This provides a new way for the selection of stress-resistant and high-quality forage varieties by the use of systemic fungal endophytes.

The past decade has witnessed significant advances in understanding the interaction between grasses and systemic fungal endophytes of the genus Epichloë, with evidence that plants have evolved multiple strategies to cope with abiotic stresses by reprogramming physiological responses. Soil nutrients directly affect plant growth, while soil microbes are also closely connected to plant growth and health. Epichloëendophytes could affect soil fertility by modifying soil nutrient contents and soil microbial diversity. Therefore, we analyze recent advances in our understanding of the role of Epichloëendophytes under the various abiotic stresses and the role of grass–Epichloësymbiosis on soil fertility. Various cool-season grasses are infected by Epichloëspecies, which contribute to health, growth, persistence, and seed survival of host grasses by regulating key systems, including photosynthesis, osmotic regulation, and antioxidants and activity of key enzymes of host physiology processes under abiotic stresses. The Epichloëendophyte offers significant prospects to magnify the crop yield, plant resistance, and food safety in ecological systems by modulating soil physiochemical properties and soil microbes. The enhancing resistance of host grasses to abiotic stresses by an Epichloëendophyte is a complex manifestation of different physiological and biochemical events through regulating soil properties and soil microbes by the fungal endophyte. The Epichloë-mediated mechanisms underlying regulation of abiotic stress responses are involved in osmotic adjustment, antioxidant machinery, photosynthetic system, and activity of key enzymes critical in developing plant adaptation strategies to abiotic stress. Therefore, the Epichloëendophytes are an attractive choice in increasing resistance of plants to abiotic stresses and are also a good candidate for improving soil fertility and regulating microbial diversity to improve plant growth.

Achnatherum inebrians is an invasive perennial grass widespread in natural grasslands of north-west China and plays an important role in grassland ecological restoration. The presence of the seed-borne endophytic fungus Epichloë gansuensis in A. inebrians promotes grass growth, increases resistance to abiotic stress, and affects the rhizosphere microbial community of host plants. However, the relationships among E. gansuensis, rhizosphere bacteria and plant contents of carbon (C), nitrogen (N), phosphorus (P) and potassium (K) during different growing seasons are not clear. We examined changes in the rhizosphere bacterial community and in nutrient contents and ratios in A. inebrians with (E+) and without (E−) E. gansuensis in May, August and December. The Shannon diversity index was higher for rhizosphere bacteria of E+ than E− plants in the three different seasons. Leaf C, N and P contents and root P and K contents were higher in E+ than E− plants in May, and leaf K and root C were higher in E+ than E− plants in August. Leaf C:N ratios were lower in E+ than E− plants in December, and leaf C:K ratios were lower in E+ than E− plants in August and December. In addition, our results indicate significant interactions among rhizosphere bacteria, C, N, P and K contents, and endophyte treatment in three different seasons. In conclusion, E. gansuensis enhanced the C, N, P and K contents of host plants, and affected nutrient ratios of A. inebrians probably by increasing rhizosphere bacterial diversity and altering rhizosphere bacterial community structure. This study provides new findings on the ecological function of the endophyte E. gansuensis, including its potential role in enhancing soil fertility. The improvements in soil fertility were utilised in extrapolating to forage grass–endophyte associations.

The installation of heterojunctions on the surfaces of carbon nanotubes (CNTs) is an effective method for promoting the charge separation processes needed for CNT-based electronics and optoelectronics applications. Conjugated polymers are proven state-of-the-art candidates for modifying the surfaces of CNTs. However, all previous attempts to incorporate conjugated polymers to CNTs resulted in unordered interfaces. Herein we show that well-defined chains of regioregular poly(3-hexylthiophene) (P3HT) were successfully grown from the surfaces of multiwalled CNTs (MWNTs) using surface-initiated Kumada catalyst-transfer polycondensation. The polymerization was found to proceed in a controlled manner as chains of tunable lengths were prepared through variation of the initial monomer-to-initiator ratio. Moreover, it was determined that large-diameter MWNTs afforded highly ordered P3HT aggregates, which exhibited a markedly bathochromically shifted optical absorption due to a high grafting density induced planarization of the polymer chains. Using ultrafast spectroscopy, the heterojunctions formed between the MWNTs and P3HT were shown to effectively overcome the binding energy of excitons, leading to photoinduced electron transfer from P3HT to MWNTs. Finally, when used as prototype devices, the individual MWNT-g-P3HT core–shell structures exhibited excellent photoresponses under a low illumination density.

1. In the results, we mistakenly described the information of Figure 9B. The correct sentence should be “The factor 1 and factor 2 explained 71.30% and 16.68% of the total variance, respectively. The 0 mmol L–1NaCl concentration showed the highest contribution (29.95%) to factor 1 in roots of E+ plants, and 200 mmol L–1NaCl concentration was significantly loaded (45.95%) on factor 2 in roots of E+ plants (Figure 9B).”