The Salinity Survival Strategy of Chenopodium quinoa: Investigating Microbial Community Shifts and Nitrogen Cycling in Saline Soils

Abstract

Quinoa is extensively cultivated for its nutritional value, and its exceptional capacity to endure elevated salt levels presents a promising resolution to the agricultural quandaries posed by salinity stress. However, limited research has been dedicated to elucidating the correlation between alterations in the salinity soil microbial community and nitrogen transformations. To scrutinize the underlying mechanisms behind quinoa’s salt tolerance, we assessed the changes in microbial community structure and the abundance of nitrogen transformation genes across three distinct salinity thresholds (1 g·kg−1, 3 g·kg−1, and 6 g·kg−1) at two distinct time points (35 and 70 days). The results showed the positive effect of quinoa on the soil microbial community structure, including changes in key populations and its regulatory role in soil nitrogen cycling under salt stress. Choroflexi, Acidobacteriota, and Myxococcota were inhibited by increased salinity, while the relative abundance of Bacteroidota increased. Proteobacteria and Actinobacteria showed relatively stable abundances across time and salinity levels. Quinoa possesses the ability to synthesize or modify the composition of keystone species or promote the establishment of highly complex microbial networks (modularity index > 0.4) to cope with fluctuations in external salt stress environments. Furthermore, quinoa exhibited nitrogen (N) cycling by downregulating denitrification genes (nirS, nosZ), upregulating nitrification genes (Archaeal amoA (AOA), Bacterial amoA (AOB)), and stabilizing nitrogen fixation genes (nifH) to absorb nitrate–nitrogen (NO3−_N). This study paves the way for future research on regulating quinoa, promoting soil microbial communities, and nitrogen transformation in saline environments.

Microbial Ecology and Site Characteristics Underlie Differences in Salinity‐Methane Relationships in Coastal Wetlands

“…The decline in Verrucomicrobiota in oligohaline sites has also been observed across the Baltic Sea salinity gradient (Herlemann et al., 2011) and demonstrates a possible preference of this phylum for non‐saline environments, although some members have been cultured at seawater salinities (Schlesner et al., 2006). Myxococcota have been identified as key components of tidal freshwater wetlands elsewhere (Morina & Franklin, 2022), and have been shown to decline with increased salinity (Zhao et al., 2023), in concordance with our results. While we found positive effects of salinity on the relative abundance of Chloroflexi, another common freshwater and estuarine wetland phylum (Huang et al., 2022; Ikenaga et al., 2010), results in other studies have shown mixed responses to low‐level salinity (Zhang et al., 2021; Zhao et al., 2020).…”

Effect of exogenous γ-aminobutyric acid on physiological property, antioxidant activity, and cadmium uptake of quinoa seedlings under cadmium stress

“…The root system has the ability to absorb and transport water, nutrients, and mineral elements [ 15 , 16 ]. The root morphological indices of quinoa seedlings under different treatments are shown in Table 3 .…”