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

Jianbin Zeng,Guang Chen,Guoping Zhang,Zhilan Ye,Shengguan Cai,Xiaoyan He,Xiaoyan Quan

doi:10.1186/s12870-018-1404-4

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.

Highlights

Potassium (K) deficiency in arable land is one of the most important factors affecting crop productivity
The reduced extent differed among three genotypes, with XZ141 showing a significant reduction in root fresh weight (RFW) and the reduction of other two genotypes was not significant (Fig. 1a)
shoot fresh weight (SFW) was significantly reduced for all three genotypes in the low K (LK)-treated plants, XZ153 showed obviously less reduction than other two genotypes (Fig. 1b)

Summary

Introduction

Potassium (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. K is abundant in the earth crust, its available forms for plant uptake, mainly ionic and exchangeable K is low in the most arable lands [5]. Considerable variation in efficiency of K uptake and utilization has been reported among genotypes for all the major crop species, indicating that the low K tolerance is genetically controlled and can be improved through genetic manipulation [6]. Little progress was made in the development of low K tolerant crop cultivars.

Objectives

Methods

Results

Discussion

Conclusion