Physiological and Transcriptome Indicators of Salt Tolerance in Wild and Cultivated Barley

Abstract

Barley is used as a model cereal to decipher salt tolerance mechanisms due to its simpler genome than wheat and enhanced salt tolerance compared to rice and wheat. In the present study, RNA-Seq based transcriptomic profiles were compared between salt-tolerant wild (Hordeum spontaneum, genotype no. 395) genotype and salt-sensitive cultivated (H. vulgare, ‘Mona’ cultivar) subjected to salt stress (300 mM NaCl) and control (0 mM NaCl) conditions. Plant growth and physiological attributes were also evaluated in a separate experiment as a comparison. Wild barley was significantly less impacted by salt stress than cultivated barley in growth and physiology and hence was more stress-responsive functionally. A total of 6,048 differentially expressed genes (DEGs) including 3,025 up-regulated and 3,023 down-regulated DEGs were detected in the wild genotype in salt stress conditions. The transcripts of salt-stress-related genes were profoundly lower in the salt-sensitive than the tolerant barley having a total of 2,610 DEGs (580 up- and 2,030 down-regulated). GO enrichment analysis showed that the DEGs were mainly enriched in biological processes associated with stress defenses (e.g., cellular component, signaling network, ion transporter, regulatory proteins, reactive oxygen species (ROS) scavenging, hormone biosynthesis, osmotic homeostasis). Comparison of the candidate genes in the two genotypes showed that the tolerant genotype contains higher functional and effective salt-tolerance related genes with a higher level of transcripts than the sensitive one. In conclusion, the tolerant genotype consistently exhibited better tolerance to salt stress in physiological and functional attributes than did the sensitive one. These differences provide a comprehensive understanding of the evolved salt-tolerance mechanism in wild barley. The shared mechanisms between these two sub-species revealed at each functional level will provide more reliable insights into the basic mechanisms of salt tolerance in barley species.

Features of Activity of the Phenylpropanoid Biosynthesis Pathway in Melanin-Accumulating Barley Grains

“…Phenolic compounds, including anthocyanin and melanin pigments, that can by synthesized in hulls and pericarp of barley grain, play diverse biochemical and molecular functions in plant physiology ( Treutter, 2006 ; Vogt, 2010 ; Kiani et al, 2021 ; Gharaghanipor et al, 2022 ). They are not only protect the seeds from damage, deterioration, and pest but also are beneficial to human health ( Rasouli et al, 2017 ).…”

“…They represent a very diverse class of plant secondary metabolites, derived from phenylalanine, and play a vital role in plant physiology. These compounds are essential structural components of cell walls, protect plants against various biotic and abiotic environmental factors, act as phytoalexins against herbivores and pathogens, and—because some of them are pigments—mediate interactions of plants with pollinators and seed dispersers ( Treutter, 2006 ; Vogt, 2010 ; Kiani et al, 2021 ; Gharaghanipor et al, 2022 ). Synthesis of all phenylpropanoids starts with the conversion of phenylalanine (or tyrosine) originating from the shikimate pathway by phenylalanine ammonia lyase (PAL; or tyrosine ammonia lyase, TAL), cinnamate 4-hydroxylase (C4H), and 4-coumaroyl coenzyme A (CoA) ligase (4CL) into p -coumaroyl-CoA, which is a precursor for all subsequent pathway branches and resulting metabolites including benzoic acids, flavonoids, monolignols, stilbenes, and coumarins ( Vogt, 2010 ; Deng and Lu, 2017 ; Figure 1 ).…”

Transcriptome profiling disclosed the effect of single and combined drought and heat stress on reprogramming of genes expression in barley flag leaf

“…Furthermore, expression co-reaction network analysis revealed that some DEGs playing various functions (e.g., genes associated with ABA signaling or lipid catabolism) had similar regulation under drought and under its combination with heat; on the other hand, the coincident expression of such DEGs was observed between heat and control conditions. Interestingly, among them, there were DEGs related to oxidoreductases that showed contrasting behavior, i.e., some were overexpressed and others were downregulated under D and HD in relation to H and C. It would seem that oxidoreductase-related genes should be generally upregulated in response to stressors, as indicated by Gharaghanipor et al (2022), who observed increased abundance of oxidoreductase-coding transcripts in stress-sensitive barley genotypes under salinity. Also, Szurman-Zubrzycka et al ( 2021) identified massive upregulation of peroxidases encoding genes in barley roots under low pH.…”

Finger millet RNA-seq reveals differential gene expression associated with tolerance to aluminum toxicity and provides novel genomic resources

“…RNA-sequencing (RNA-seq) is an efficient and less expensive next-generation sequencing (NGS) method that has broad applications, including the identification of differentially expressed genes and determining pathways in crops grown under different stress (Khatiwada et al, 1996;Mattiello et al, 2010;Xu et al, 2017;Gharaghanipor et al, 2022). There has been no published transcriptome-based research on Al-tolerance in finger millet to the best of our knowledge.…”