Key Lab of Plant Stress Research, College of Life Science, Shandong Normal University, Jinan, 250014, Shandong, China.
CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute of Computational Biology, Shanghai Institutes for Biological Sciences, Shanghai, 200031, China.
Plant Mol Biol. 2016 Jun;91(3):241-56. doi: 10.1007/s11103-016-0460-0. Epub 2016 Mar 3.
Limonium bicolor, a typical recretohalophyte that lives in saline environments, excretes excessive salt to the environment through epidermal salt glands to avoid salt stress. The aim of this study was to screen for L. bicolor genes involved in salt secretion by high-throughput RNA sequencing. We established the experimental procedure of salt secretion using detached mature leaves, in which the optimal salt concentration was determined as 200 mM NaCl. The detached salt secretion system combined with Illumina deep sequencing were applied. In total, 27,311 genes were annotated using an L. bicolor database, and 2040 of these genes were differentially expressed, of which 744 were up-regulated and 1260 were down-regulated with the NaCl versus the control treatment. A gene ontology enrichment analysis indicated that genes related to ion transport, vesicles, reactive oxygen species scavenging, the abscisic acid-dependent signaling pathway and transcription factors were found to be highly expressed under NaCl treatment. We found that 102 of these genes were likely to be involved in salt secretion, which was confirmed using salt-secretion mutants. The present study identifies the candidate genes in the L. bicolor salt gland that are highly associated with salt secretion. In addition, a salt-transporting pathway is presented to explain how Na(+) is excreted by the salt gland in L. bicolor. These findings will shed light on the molecular mechanism of salt secretion from the salt glands of plants.
双色补血草,一种典型的盐生植物,生活在盐环境中,通过表皮盐腺将多余的盐分排泄到环境中,以避免盐胁迫。本研究旨在通过高通量 RNA 测序筛选与盐分泌相关的双色补血草基因。我们建立了使用分离成熟叶片进行盐分泌的实验程序,其中确定了最佳盐浓度为 200mM NaCl。采用分离的盐分泌系统与 Illumina 深度测序相结合。总共使用双色补血草数据库注释了 27311 个基因,其中 2040 个基因差异表达,与对照处理相比,744 个基因上调,1260 个基因下调。GO 富集分析表明,与离子转运、液泡、活性氧清除、ABA 依赖信号通路和转录因子相关的基因在 NaCl 处理下高度表达。我们发现其中 102 个基因可能参与盐分泌,这通过盐分泌突变体得到了证实。本研究鉴定了与双色补血草盐腺盐分泌高度相关的候选基因。此外,还提出了一个盐转运途径来解释 Na+ 如何通过双色补血草的盐腺排泄。这些发现将为植物盐腺盐分泌的分子机制提供线索。