Metabolite Profiling of Barley Grains Subjected to Water Stress: To Explain the Genotypic Difference in Drought-Induced Impacts on Malting Quality

Abstract

Grain weight and protein content will be reduced and increased, respectively, when barley is subjected to water stress after anthesis, consequently deteriorating the malt quality. However, such adverse impact of water stress differs greatly among barley genotypes. In this study, two Tibetan wild barley accessions and two cultivated varieties differing in water stress tolerance were used to investigate the genotypic difference in metabolic profiles during grain-filling stage under drought condition. Totally, 71 differently accumulated metabolites were identified, including organic acids, amino acids/amines, and sugars/sugar alcohols. Their relative contents were significantly affected by water stress for all genotypes and differed distinctly between the wild and cultivated barleys. The principal component analysis of metabolites indicated that the Tibetan wild barley XZ147 possessed a unique response to water stress. When subjected to water stress, the wild barley XZ147 showed the most increase of β-amylase activity among the four genotypes, as a result of its higher lysine content, less indole-3-acetic acid (IAA) biosynthesis, more stable H2O2 homeostasis, and more up-regulation of BMY1 gene. On the other hand, XZ147 had the most reduction of β-glucan content under water stress than the other genotypes, which could be explained by the faster grain filling process and the less expression of β-glucan synthase gene GSL7. All these results indicated a great potential for XZ147 in barley breeding for improving water stress tolerance.

Evaluation of Two Major Rhodiola Species and the Systemic Changing Characteristics of Metabolites of Rhodiola crenulata in Different Altitudes by Chemical Methods Combined with UPLC-QqQ-MS-Based Metabolomics

“…l -asparagine is well-known to be located at the beginning of the aspartate biosynthetic pathway, thus its upregulation may be indicative of activation of the aspartate biosynthetic pathway in Rhodiola crenulata, which is consistent with upregulation of l -(+)-lysine and l -isoleucine, which are the downstream products of this pathway. Reports have shown that lysine helps improve plant drought tolerance [ 25 ] and isoleucine is closely related to plant resistance to salt stress [ 26 ] and the growth of germinating embryos [ 60 ].…”

Variable Levels of Tolerance to Water Stress (Drought) and Associated Biochemical Markers in Tunisian Barley Landraces

“…Carbohydrates have also been reported as major osmolytes in barley [ 7 ], especially sucrose and malate [ 33 , 55 ] and some others such as ribose and 1-kestose [ 6 ]. We reported a strong increase in the levels of total soluble sugars, but no correlation was found with the relative stress tolerance of genotypes.…”

“…Munns et al [ 1 ] highlighted that barley is the most salt tolerant cereal, and its tolerance to drought or biotic stresses such as fungal disease is well-known [ 2 ]. There is a plethora of information on barley’s responses to abiotic stress, including recent studies and review articles on physiological, biochemical [ 2 , 3 , 4 , 5 ], metabolomics [ 6 , 7 ] and transcriptomics [ 8 , 9 , 10 , 11 ] aspects. Being an annual diploid plant species, with a small number of chromosomes (2 n = 14) and a huge range of genetic variability that accounts for different levels of stress tolerance, barley is a model species among crops for deciphering stress tolerance mechanisms, and hence has been subjected to many genetic studies in relation to stress tolerance, ranging from genetic variability analysis [ 12 , 13 ] to marker assisted selection in conjunction with the use of quantitative trait loci (QTLs) [ 14 , 15 ].…”

Grain yield, agronomic traits, and protein content of two- and six-row barley genotypes under terminal drought conditions

“…This is the case in Mediterranean and Southeastern European environments where small grain cereals usually mature under terminal drought conditions. Studies showed that yield components and protein content (PC) decreased and increased, respectively, when barley was subjected to water stress after anthesis (Samarah et al, 2009;Wu et al, 2017). Dry matter for grain filling is a result of a post-anthesis photosynthetic activity and remobilization of storage reserves deposited prior to anthesis.…”