AUTHOR=Sharma Vijay K. , Parmar Shobhika , Tang Wenting , Hu Haiyan , White James F. , Li Haiyan 

TITLE=Effects of fungal seed endophyte FXZ2 on Dysphania ambrosioides Zn/Cd tolerance and accumulation

JOURNAL=Frontiers in Microbiology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.995830

DOI=10.3389/fmicb.2022.995830

ISSN=1664-302X

ABSTRACT=Metal induced oxidative stress in the contaminated soils affects the plant growth. In the present study, we evaluated the role of seed endophyte FXZ2 on Dysphania ambrosioides Zn/Cd tolerance and accumulation. A series of pot experiments were conducted under variable Zn (500, 1000, 1500 mg kg-1) and Cd (5, 15, 30, 60 mg kg-1). The results demonstrated that FXZ2-inoculation significantly enhanced the growth of D. ambrosioides, improved its chlorophyll and GSH content. In the rhizosphere, FXZ2 inoculation changed the chemical speciation of Zn/Cd and thus affected their uptake and accumulation in host plants. The exchangeable and carbonate-bound fractions (F1+F2) of Zn decreased in the rhizosphere of FXZ2-inoculated plants (E+) as compared to non-inoculated plants (E-) under Zn stress (500 and 1000 mg kg-1), correspondingly, Zn in the shoots of E+ decreased (p<0.05). However, at Cd stress (30 and 60 mg kg-1), the F1+F2 fractions of Cd in E+ rhizospheric soils increased, subsequently, Cd in the shoots of E+ increased (p<0.05). FXZ2 could exogenously secrete phytohormones IAA, GA, and JA. The study suggests that seed endophyte FXZ2 can increase Zn/Cd tolerance of host plant by altering Zn/Cd speciation in rhizospheric soils, as well as exogenous production of phytohormones to promote growth, lowering oxidative damage while enhancing antioxidant properties. For Zn/Cd accumulation, it has opposite effects: Zn uptake in E+ plants was significantly (p<0.05) decreased, while Cd accumulation in E+ plants was significantly (p<0.05) increased. Thus, FXZ2 has excellent application prospects in Cd phytoextraction and decreasing Zn toxicity in agriculturally important crops.