Open AccessThe alleviation of manganese toxicity by ammonium in sugarcane is related to pectin content, pectin methyl esterification, and nitric oxide
Author(s) -
Ling Gui Zhi,
Xiao Jing Lin,
Yang Shu,
Li Dong Ling,
Tang Xin Lian,
Wang Xiao Xia,
Zhang Mu Qing,
Li Xiao Feng
Publication year - 2022
Publication title -
gcb bioenergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.378
H-Index - 63
eISSN - 1757-1707
pISSN - 1757-1693
DOI - 10.1111/gcbb.12936
Subject(s) - pectin , chemistry , cell wall , ammonium , nitrate reductase , toxicity , nitric oxide , nitrate , food science , horticulture , nuclear chemistry , biochemistry , enzyme , biology , organic chemistry
Abstract Coexistence of ammonium ( NH 4 + ) with manganese (Mn) in acid soils may facilitate the alleviation of Mn toxicity to plants. However, the effect of NH 4 + on Mn toxicity and the corresponding mechanisms are unclear. In this study, the effects of NH 4 + and nitrate ( NO 3 ‐ ) on Mn toxicity, cell wall properties, and nitric oxide (NO) signaling in sugarcane were compared. NH 4 + alleviated Mn‐induced chlorosis in sugarcane seedlings and increased seedling biomass compared with NO 3 ‐ . Exogenous application of NH 4 + decreased the root cell wall pectin content and methyl esterase (PME) activity, but increased the degree of root pectin esterification (PMD). These changes were accompanied by reductions in the Mn content in roots, leaves, root cell wall, and cell wall pectin. An analysis of adsorption kinetic revealed less Mn‐adsorption capacity in cell walls extracted from NH 4 + ‐fed than from NO 3 ‐ ‐fed sugarcane. Mn induced NO accumulation in sugarcane roots, but NH 4 + ‐fed seedlings accumulated less NO. Exogenous application of the NO donor sodium nitroprusside increased the Mn content of root cell wall pectin in NH 4 + ‐fed sugarcane, while the NO scavenger 2‐(4‐carboxyphenyl)‐4,4,5,5‐tetramethylimidazoline‐1‐oxyl‐3‐oxid decreased the Mn content in NO 3 ‐ ‐fed sugarcane. These treatments eliminated the difference in the pectin Mn content between NH 4 + ‐fed and NO 3 ‐ ‐fed sugarcane, as did a similar treatment with the nitrate reductase inhibitor tungstate, which decreased root cell wall pectin content and NO accumulation. These results suggest that (i) NH 4 + alleviates Mn toxicity in sugarcane by reducing root pectin accumulation and root cell wall PME activity, thereby increasing cell wall PMD and decreasing both the Mn‐binding capacity of cell wall and Mn accumulation, and (ii) NO mediates the accumulation of both pectin and Mn in response to different forms of nitrogen. The physiological mechanisms underlying the alleviation of ammonium on Mn phytotoxicity were clarified, which provided important implication for agricultural production and ecosystem functioning in acid soil.