Gharaghanipor Narges, Arzani Ahmad, Rahimmalek Mehdi, Ravash Rudabeh
Department of Agronomy and Plant Breeding, College of Agriculture, Isfahan University of Technology, Isfahan, Iran.
Department of Horticulture, College of Agriculture, Isfahan University of Technology, Isfahan, Iran.
Front Plant Sci. 2022 Apr 14;13:819282. doi: 10.3389/fpls.2022.819282. eCollection 2022.
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 (, genotype no. 395) genotype and salt-sensitive cultivated (, '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.
由于大麦的基因组比小麦简单，且与水稻和小麦相比耐盐性更强，因此被用作模式谷物来解析耐盐机制。在本研究中，比较了耐盐野生型（基因型编号395）和盐敏感栽培型（“莫娜”品种）在盐胁迫（300 mM NaCl）和对照（0 mM NaCl）条件下基于RNA-Seq的转录组图谱。在另一个单独的实验中还评估了植物生长和生理特性以作比较。野生大麦在生长和生理方面受盐胁迫的影响明显小于栽培大麦，因此在功能上对胁迫的反应更强。在盐胁迫条件下的野生基因型中，共检测到6048个差异表达基因（DEG），其中包括3025个上调DEG和3023个下调DEG。盐敏感大麦中与盐胁迫相关基因的转录本比耐盐大麦中的低得多，共有2610个DEG（580个上调和2030个下调）。基因本体论（GO）富集分析表明，这些DEG主要富集在与胁迫防御相关的生物学过程中（例如，细胞成分、信号网络、离子转运蛋白、调节蛋白、活性氧（ROS）清除、激素生物合成、渗透稳态）。两种基因型中候选基因的比较表明，耐盐基因型比敏感基因型含有更多功能和有效的耐盐相关基因，且转录本水平更高。总之，耐盐基因型在生理和功能属性上始终表现出比敏感基因型更好的耐盐胁迫能力。这些差异为深入了解野生大麦进化出的耐盐机制提供了全面认识。在每个功能水平上揭示的这两个亚种之间的共同机制将为大麦属植物耐盐的基本机制提供更可靠的见解。
