Arbuscular mycorrhizal fungi modulates dynamics tolerance expression to mitigate drought stress in Ephedra foliata Boiss

Thesis

2020

Published in: https://doi.org/10.1016/j.sjbs.2019.10.008

, Al-Bandari Fahad Al-Arjani, Abeer Hashem, Elsayed Fathi Abd_Allah. . 2020

a b s t r a c t
Arbuscular mycorrhizal fungi (AMF) are one of the most important drivers of soil ecosystem dynamics.
AMF have the potential to improve plant growth and development by modulating key hormonal pathways,
which result in decreasing the adverse impact of abiotic stress, such as drought. Pot experiments
were conducted in this study to investigate the ability of AMF to ameliorate the adverse impact of
drought in Ephedra foliate. Non-inoculated AMF E. foliate (Ef) plants, exhibited reduced growth in
response to drought stress with a concomitant lowering of chlorophyll pigments, relative to nonstressed
and AMF inoculated plant. AMF inoculated E. foliate showed improved nitrogen metabolism
by positively regulating nitrate and nitrite reductase activity which results in greater ammonium availability
for the synthesis of amino acids. Inoculation with AMF also increased antioxidant enzyme activity,
ascorbic acid contents, and reduction in glutathione level. This resulted in significant amelioration of
oxidative damage to plant membranes by restricting the excess generation of reactive oxygen species
(ROS), such as hydrogen peroxide. Greater content of proline, glucose, and total soluble protein in
AMF-inoculated plants provided further benefit to E. foliate plants and their ability to withstand drought
stress, and also evident by a greater level of sucrose phosphate synthase activity. AMF significantly
enhanced the uptake of essential nutrients like K, Mg, and Ca. Importantly, higher concentrations of plant
hormones, including indole acetic acid (IAA), indole butyric acid (IBA), gibberellic acid (GA), and abscisic
acid (ABA), were maintained in AMF-inoculated Ef plants. AMF inoculation also boosted phosphorous
metabolism by increasing alkaline and acid phosphatase enzyme activity. In summary, AMFinoculation
of Ef plants significantly reduced the deleterious effect of drought stress by up-regulating
the antioxidant defense system, synthesis of osmolytes, and maintaining phytohormone levels.

• Publication Work Type: دكتوراة