Root and leaf metabolite profiles analysis reveals the adaptive strategies to low potassium stress in barley

Abstract

BackgroundPotassium (K) deficiency in arable land is one of the most important factors affecting crop productivity. Development of low K (LK) tolerant crop cultivars is regarded as a best economic and effective approach for solving the issue of LK. In previous studies, we found a wider variation of LK tolerance in the Tibetan wild barley accessions than cultivated barley. However, the mechanism of LK tolerance in wild barley is still elusive.ResultsIn this study, two wild barley genotypes (XZ153, LK tolerant and XZ141, LK sensitive) and one cultivar (LuDaoMai, LK tolerant) was used to investigate metabolome changes in response to LK stress. Totally 57 kinds of metabolites were identified in roots and leaves of three genotypes at 16 d after LK treatment. In general, accumulation of amino acids and sugars was enhanced in both roots and leaves, while organic acids were reduced under LK stress compared to the control. Meanwhile, the concentrations of the negatively charged amino acids (Asp and Glu) and most organic acids was reduced in both roots and leaves, but more positively charged amino acids (Lys and Gln) were increased in three genotypes under LK. XZ153 had less reduction than other two genotypes in biomass and chlorophyll content under LK stress and showed greater antioxidant capacity as reflected by more synthesis of active oxygen scavengers. Higher LK tolerance of XZ153 may also be attributed to its less carbohydrate consumption and more storage of glucose and other sugars, thus providing more energy for plant growth under LK stress. Moreover, phenylpropanoid metabolic pathway mediated by PAL differed among three genotypes, which is closely associated with the genotypic difference in LK tolerance.ConclusionsLK tolerance in the wild barley is attributed to more active phenylpropanoid metabolic pathway mediated by PAL, energy use economy by reducing carbohydrate consumption and storage of glucose and other sugars, and higher antioxidant defense ability under LK stress.Electronic supplementary materialThe online version of this article (10.1186/s12870-018-1404-4) contains supplementary material, which is available to authorized users.

Adaptation of Plants to Salt Stress: Characterization of Na+ and K+ Transporters and Role of CBL Gene Family in Regulating Salt Stress Response

“…Under this model, the K + availability diminution in the area leads to a decrease of K + concentration in the cytoplasm, which would lift the allosteric inhibition of transport, thus causing absorption capacity augmentation. Another hypothesis, non-exclusive of the previous one, is based on the observation of modifications of the membrane polypeptide equipment when the plants are cultivated in a weakly concentrated potassium area, confirming the installation of new transport systems in barley [57], especially high-affinity transporters in barley [58], wheat [59], and Arabidopsis thaliana, [55,60]. In Arabidopsis, studies using the patch-clamp technical revealed that K + deficiency increases the activity of IRK-type channels (inward rectifying K + channel).…”

Multi-Omics Analyses Reveal the Molecular Mechanisms Underlying the Adaptation of Wheat (Triticum aestivum L.) to Potassium Deprivation

“…Additionally, metabolomics-based studies have revealed intermediate metabolites relevant to various plant physiological characteristics under different abiotic stress conditions. Zeng et al (2018) identified 57 kinds of metabolites as well as differences in the phenylpropanoid metabolic pathway mediated by phenylalanine ammonia-lyase (PAL) among three genotypes, which may be closely associated with the genotypic differences in K-deficiency tolerance. However, there are few reports describing integrated analyses of the genes and metabolites involved in the K-deficiency stress response pathways in wheat.…”

Metabolite Profile of Xylem Sap in Cotton Seedlings Is Changed by K Deficiency

“…Meanwhile, the concentration of Ca 2+ as the secondary messenger in plant cells increased ( Table 2 ), indicating that Ca 2+ could be used as a response signal of cotton seedlings to LK stress ( Girón-Calle and JayForman, 2000 ; Guo et al, 2013 ). To maintain charge balance under LK stress, plants enhance positively charged amino acids and inhibit negatively charged amino acids; these are strategies for plants to maintain charge balance under LK stress ( Zeng et al, 2018 ). In this study, we observed that the contents of amino acid levels in the xylem sap significantly increased under LK stress (pH = 5.41), and the FCs of positively charged L-histidine (pI = 7.59) and L-tryptophan (pI = 5.89) were higher than that of negatively charged L-aspartic acid (pI = 2.97) ( Table 5 ), which may have been caused by the requirement of charge balance.…”

“…K deficiency is a common abiotic stress in agricultural production ( Hosseini et al, 2017 ; Xu et al, 2020 ). It can lead to increases in the concentrations of free sugars in the leaves of bean ( Cakmak et al, 1994 ), cotton ( Bednarz and Oosterhuis, 1999 ; Pettigrew, 1999 ; Hu et al, 2017 ), potato ( Koch et al, 2018 ), and oilseed rape ( Pan et al, 2017 ), the roots of alfalfa ( Jungers et al, 2019 ), rice ( Ma et al, 2012 ; Chen et al, 2015 ), and sugar beet ( Aksu and Altay, 2020 ), and the leaves and the roots of Arabidopsis ( Armengaud et al, 2009 ), barley ( Zeng et al, 2018 ), and tomato ( Sung et al, 2015 ). In addition, excessive accumulation of free amino acids, especially proline, has been reported for tobacco ( Ren et al, 2016 ), cotton ( Hu et al, 2017 ), oilseed rape ( Lu et al, 2019 ), barley ( Zeng et al, 2018 ), and Arabidopsis ( Armengaud et al, 2009 ).…”