Amelioration of saline-alkali land by cultivating Melia azedarach and
characterization of underlying mechanisms via metabolome analysis
Abstract
Soil salinization is a serious problem leading to ecological
degradation. Melia azedarach is highly salt-tolerant, and its
application to saline-alkali land is a promising strategy for restoring
degraded lands. In this study, we analyzed the soil properties and
metabolome of M. azedarach roots grown in low- (< 3
g/kg; L), medium- (5~8 g/kg; M), and high-
(> 10 g/kg; H) salinity soils to explore the amelioration
effect and adaptation mechanism of M. azedarach to soils with
differential salinity. Cultivation of M. azedarach was associated
with a decrease in the concentration of Na + and
increases in organic matter content and alkaline phosphatase and urease
activities in the rhizosphere soil. The metabolome analysis revealed
that a total of 382 (ESI+) and 277 (ESI-) differential metabolites
(DEMs) were detected. The number of DEMs in roots rose with increased
soil salinity, such as sugars and flavonoids in H vs. L, and amino acids
in M vs. L. The most up-regulated DEMs were 13-S-hydroxyoctadecadienoic
acid, 2’-Deoxyuridine and 20-hydroxyleukotriene B4. Combined analysis of
soil properties and M. azedarach DEMs indicated that alkaline
phosphatase activity was positively correlated with traumatic acid
concentration. Taken together, these results indicate that M.
azedarach has the potential to reduce soil salinity and enhance soil
enzyme activity, and it can adapt to salt stress by regulating
metabolites like sugars, amino acids, and flavonoids . This study
provided a basis for understanding the mechanism underlying the
adaptation of M. azedarach to saline-alkali soil and its
amelioration.