Metabolite Profiling of Diverse Rice Germplasm and Identification of Conserved Metabolic Markers of Rice Roots in Response to Long-Term Mild Salinity Stress

Abstract

The sensitivity of rice to salt stress greatly depends on growth stages, organ types and cultivars. Especially, the roots of young rice seedlings are highly salt-sensitive organs that limit plant growth, even under mild soil salinity conditions. In an attempt to identify metabolic markers of rice roots responding to salt stress, metabolite profiling was performed by 1H-NMR spectroscopy in 38 rice genotypes that varied in biomass accumulation under long-term mild salinity condition. Multivariate statistical analysis showed separation of the control and salt-treated rice roots and rice genotypes with differential growth potential. By quantitative analyses of 1H-NMR data, five conserved salt-responsive metabolic markers of rice roots were identified. Sucrose, allantoin and glutamate accumulated by salt stress, whereas the levels of glutamine and alanine decreased. A positive correlation of metabolite changes with growth potential and salt tolerance of rice genotypes was observed for allantoin and glutamine. Adjustment of nitrogen metabolism in rice roots is likely to be closely related to maintain the growth potential and increase the stress tolerance of rice.

Allantoin accumulation through overexpression ofureide permease1improves rice growth under limited nitrogen conditions

“…In this study, we evaluated the activation tagging plants overexpressing the rice ureide permease1 ( OsUPS1 OX ) and showing significant allantoin accumulation in panicles of 14 DAF plants compared to WT (Figure a). Though present in rice, the role of allantoin as a N source in rice is not established yet but has been reported to be involved in important biological processes such as stress tolerance (Casartelli et al ., ; Degenkolbe et al ., ; Nam et al ., ) and as a growth enhancer (Wang et al ., ). Allantoin is a stable nitrogen‐rich heterocyclic compound that is a product of purine metabolism and a form N storage in ureide‐metabolizing plants.…”

Metabolomics Analysis Reveals the Alkali Tolerance Mechanism in Puccinellia tenuiflora Plants Inoculated with Arbuscular Mycorrhizal Fungi

“…The application of metabolomics methods offers a rational way to reveal the implications of these metabolic changes on a broad scale [31]. Currently, metabolomics-based technologies have been broadly employed to clarify the metabolic responses of various plants (both halophytes and glycophytes) to salt stress, such as Hordeum vulgare [32], Oryza sativa [33], Suaeda corniculata [34], Glycine max [30], and Zea mays [35]. These studies accelerate the understanding of the molecular mechanisms of plant salt tolerance at the metabolic level.…”

Opposite fates of the purine metabolite allantoin under water and nitrogen limitations in bread wheat

“…Allantoin and allantoate (also known as ureides) are the main products of atmospheric N 2 fixation in root nodules, which are then translocated to the shoot (Herridge et al 1978;Pate et al 1980). In recent years, the ureide allantoin has gained attention by the scientific community as several metabolomics studies reported this metabolite to accumulate in a broad range of plant species under drought (Bowne et al 2011;Oliver et al 2011;Silvente et al 2012;Degenkolbe et al 2013;Yobi et al 2013;Casartelli et al 2018), high salt (Kanani et al 2010;Wu et al 2012;Nam et al 2015;Wang et al 2016), cold (Kaplan et al 2004) and sulfate starvation (Nikiforova et al 2005). In contrast, allantoin was found to be reduced under prolonged N deficiency in maize and rice (Amiour et al 2012;Coneva et al 2014).…”