Dark septate endophyte inoculation enhances antioxidant activity in Astragalus membranaceus var. mongholicus under heat stress

Abstract

The influence of dark septate endophytic (DSE) on the antioxidant activity of Astragalus membranaceus var. mongholicus under heat stress was investigated. A. membranaceus plants, with or without DSE inoculation, were grown at 28°C for 8 weeks in a greenhouse and subsequently subjected to heat stress conditions (42°C) in an artificial climate chamber. DSE inoculation significantly decreased the malondialdehyde (MDA) content during the initial three days of heat stress. The activities of superoxide dismutase (SOD) and peroxidase (POD) of A. membranaceus leaves were significantly enhanced by DSE inoculation under heat stress, with SOD activities being 63–81% higher than in other treatments. The glutathione (GSH) and putrescine (Put) contents accumulated significantly on the third day under heat stress with DSE inoculation. Additionally, the contents of soluble sugars and proline (Pro) exhibited significant increases on the seventh day of heat stress and were 33–55% and 81–83% higher than in other treatments, respectively. Three‐way ANOVA shows that DSE inoculation under heat stress exerted a significant impact on MDA. Multivariate linear regression and structural equality modelling (SEM) further show that the interaction among these antioxidants significantly decreased MDA content and maintained the normal function of cell membranes. In conclusion, DSE inoculation enhanced the heat tolerance of A. membranaceus by boosting its antioxidant capacity and reducing MDA production. This study highlights the potential of utilizing DSE as a strategy to enhance plant heat tolerance.

Alleviation of Salt Stress and Changes in Glycyrrhizic Acid Accumulation by Dark Septate Endophytes in Glycyrrhiza glabra Grown under Salt Stress

“…However, studies on the mechanism of DSE improving the resistance of plants to salt stress mainly focus on ordinary plants, while the mechanism of action of DSE on medicinal plants in saline soils remains unclear. At present, the main reason for the lack of research on the effects of DSE on medicinal plants in salt stress environments is due to the specificity of medicinal plants. , However, with increasing research indicating that DSE can be widely colonized in various medicinal plants, its role in medicinal plants has also attracted widespread attention . DSE also plays an important role in medicinal plants.…”