Improved Tolerance of Artemisia ordosica to Drought Stress via Dark Septate Endophyte (DSE) Symbiosis

Abstract

Dark septate endophytes (DSEs) usually colonize plant roots, especially in stress environments. However, their relationship with plants ranges from beneficial to harmful and has remained largely uncharacterized. In the present study, 14 DSE species grouped into 11 genera were isolated from the roots of a desert plant, Artemisia ordosica, which is widely distributed in northwest China. Three dominant DSE species—Paraphoma chrysanthemicola (Pc), Alternaria chartarum (Ac), and Acrocalymma vagum (Av)—were selected and tested for their resistance to drought in vitro. Furthermore, we characterized the responses of A. ordosica under drought conditions in relation to the presence of these DSEs following inoculation. The results showed that all three strains grew well under in vitro drought stress, and the biomass of Ac and Av was significantly higher than that of the unstressed control. The effects of DSE inoculation on the growth of A. ordosica under drought stress varied according to the different DSE species but were generally beneficial. Under drought stress, Av and Pc promoted plant growth, antioxidant enzyme activity, and root development of the hosts. The Ac strain conferred obvious positive effects on the antioxidant enzyme activity of the hosts. In general, Av and Pc demonstrated better application potential for improving the drought resistance of A. ordosica.

Effects of Dark Septate Endophyte Symbiosis on Defenses of Plants Against Insect Herbivory

“…Considering that the plants were germinated on PDA media (which holds water) and regularly watered for the week before survival rate was counted, my results agree with those of Li et al (2022) in that well-watered plants were parasitized by the DSEs. However, Li et al 2022 also highlights the fact that the effects of DSEs vary based on species and do not behave similarly as a group. Thus, I plan to view DSE species more individually in the future while also taking into consideration that they likely do not share ancestry (Hughes et al 2020).…”

“…The seedling survival rates of experiment 1 were initially surprising as I would have expected the plants inoculated with DSEs to support plant growth, as would be consistent with . However, the DSE drought study by Li et al (2022) found that plants inoculated with DSE Alternaria chartarum with high water availability had lower biomass than plants in drought, though other DSEs exhibited different or even opposite trends. Considering that the plants were germinated on PDA media (which holds water) and regularly watered for the week before survival rate was counted, my results agree with those of Li et al (2022) in that well-watered plants were parasitized by the DSEs.…”

“…However, the DSE drought study by Li et al (2022) found that plants inoculated with DSE Alternaria chartarum with high water availability had lower biomass than plants in drought, though other DSEs exhibited different or even opposite trends. Considering that the plants were germinated on PDA media (which holds water) and regularly watered for the week before survival rate was counted, my results agree with those of Li et al (2022) in that well-watered plants were parasitized by the DSEs. However, Li et al 2022 also highlights the fact that the effects of DSEs vary based on species and do not behave similarly as a group.…”

“…Dark septate endophytes (or DSE) are underground fungi that are just as common as arbuscular mycorrhizal fungi (Mandyam & Jumpponen 2005), yet knowledge concerning their ecology is sparse (Li et al 2022). They are root fungi with characteristic melanized septate hyphal structures (Mandyam & Jumpponen 2005).…”

Colonization of root endophytic fungus Serendipita indica improves drought tolerance of Pinus taeda seedlings by regulating metabolome and proteome

“…As functions of symbiosis of mycorrhizal fungi (Chandrasekaran, 2022;Begum et al, 2023;Zou et al, 2023), plant growth-promoting rhizobacteria (PGPR) (Shankar and Prasad, 2023;Tanveer et al, 2023;Zhao et al, 2023), and dark septate endophytes (DSE) (Li et al, 2022;He C. et al, 2022;Liu et al, 2023) during drought stress, root endophytic fungi also play important roles in increasing tolerance to drought stress of their host plants (Azevedo et al, 2021;Manzur et al, 2022;Zuo et al, 2022). S. indica is also a root endophytic fungus, and it improves drought tolerance of their host plants, as described above.…”