Wang Zhaodi, Wang Lei, Liang Xinran, Zhang Guangqun, Li Zuran, Yang Zhixin, Zhan Fangdong
College of Resources and Environment, Yunnan Agricultural University, Kunming, Yunnan, China.
College of Landscape and Horticulture, Yunnan Agricultural University, Kunming, Yunnan, China.
Front Plant Sci. 2024 May 24;15:1349202. doi: 10.3389/fpls.2024.1349202. eCollection 2024.
Arbuscular mycorrhizal fungi (AMF) and dark septate endophytic fungi (DSEs) generally coexist in the roots of plants. However, our understanding of the effects of their coexistence on plant growth and stress resistance is limited.
In the present study, the effects of single and dual inoculation of AMF and DSE on the growth, photosynthetic physiology, glutathione (GSH) metabolism, endogenous hormones, and cadmium (Cd) content of maize under 25 mg•kg Cd stress were investigated.
Compared with that after the non-inoculation treatment, AMF+DSE co-inoculation significantly increased the photosynthetic rate (Pn) of maize leaves; promoted root GSH metabolism; increased the root GSH concentration and activity of γ-glutamyl cysteine synthase (γ-GCS), ATP sulfatase (ATPS) and sulfite reductase (SIR) by 215%, 117%, 50%, and 36%, respectively; and increased the concentration of endogenous hormones in roots, with increases in zeatin (ZR), indole-3 acetic acid (IAA), and abscisic acid (ABA) by 81%, 209%, and 72%, respectively. AMF inoculation, DSE inoculation and AMF+DSE co-inoculation significantly increased maize biomass, and single inoculation with AMF or DSE increased the Cd concentration in roots by 104% or 120%, respectively. Moreover, significant or highly significant positive correlations were observed between the contents of ZR, IAA, and ABA and the activities of γ-GCS, ATPS, and SIR and the glutathione (GSH) content. There were significant or highly significant positive interactions between AMF and DSE on the Pn of leaves, root GSH metabolism, and endogenous hormone contents according to two-way analysis of variance. Therefore, the coexistence of AMF and DSE synergistically enhanced the Cd tolerance of maize.
丛枝菌根真菌（AMF）和暗隔内生真菌（DSE）通常共存于植物根系中。然而，我们对它们共存对植物生长和抗逆性影响的了解有限。
在本研究中，研究了AMF和DSE单接种及双接种对25 mg•kg镉胁迫下玉米生长、光合生理、谷胱甘肽（GSH）代谢、内源激素和镉（Cd）含量的影响。
与未接种处理相比，AMF+DSE双接种显著提高了玉米叶片的光合速率（Pn）；促进了根系GSH代谢；使根系GSH浓度以及γ-谷氨酰半胱氨酸合成酶（γ-GCS）、ATP硫酸化酶（ATPS）和亚硫酸盐还原酶（SIR）的活性分别提高了215%、117%、50%和36%；并增加了根系内源激素的浓度，其中玉米素（ZR）、吲哚-3-乙酸（IAA）和脱落酸（ABA）分别增加了81%、209%和72%。AMF接种、DSE接种以及AMF+DSE双接种均显著增加了玉米生物量，单独接种AMF或DSE分别使根系Cd浓度提高了104%或120%。此外，ZR、IAA和ABA的含量与γ-GCS、ATPS和SIR的活性以及谷胱甘肽（GSH）含量之间存在显著或极显著的正相关。根据双因素方差分析，AMF和DSE在叶片Pn、根系GSH代谢和内源激素含量方面存在显著或极显著的正相互作用。因此，AMF和DSE的共存协同增强了玉米对镉的耐受性。
