A better understanding of the molecular effects of salinity stress is key to improving salt tolerance in Zea mays. In this study, we combined phenotyping with transcript profiling to study genotype-specific differences in salt tolerance in Zea mays. An extensive phenotypic screening identified two genotypes with extreme phenotypic differences in tolerance toward salt stress. De novo RNA-seq analysis of the selected salt-tolerant (R9) and salt-sensitive (S46) genotype was performed to unveil the molecular mechanisms underlying the differences in salt tolerance between the two genotypes. A number of 5884 and 5556 unique transcripts were identified that were uniquely expressed in the R9 and S46 genotypes, respectively. GO enrichment showed that processes such as cellular response to calcium ion, and regulation of secondary metabolites biosynthesis has been highly diverged between the two genotypes at the transcriptome level. Comparing salt treated with control samples for each genotype showed enrichment for salt tolerance related mechanisms, i.e., potassium ion transport and cation/ion transmembrane transport, in the tolerant genotype only. We hypothesized that more efficient potassium uptake and different response to calcium ions can contribute to better ionic hemostasis and subsequently more salt tolerance for the R9 genotype.

更好地了解盐分胁迫的分子效应是提高玉米耐盐性的关键。在这项研究中，我们将表型分析与转录本分析相结合，以研究玉米耐盐性的基因型特异性差异. 广泛的表型筛选确定了两种对盐胁迫的耐受性具有极端表型差异的基因型。对选定的耐盐 (R9) 和盐敏感 (S46) 基因型进行从头 RNA-seq 分析，以揭示两种基因型之间耐盐差异的分子机制。鉴定了许多 5884 和 5556 个独特的转录本，它们分别在 R9 和 S46 基因型中唯一表达。GO富集表明，细胞对钙离子的反应和次级代谢物生物合成的调节等过程在转录组水平上两种基因型之间存在很大差异。比较每种基因型用对照样品处理的盐显示了耐盐相关机制的富集，即 钾离子转运和阳离子/离子跨膜转运，仅在耐受基因型中。我们假设更有效的钾吸收和对钙离子的不同反应有助于更好的离子止血，随后对 R9 基因型有更高的耐盐性。