Comparative Analysis of the Chrysanthemum Leaf Transcript Profiling in Response to Salt Stress

Salt stress has some remarkable influence on chrysanthemum growth and productivity. To understand the molecular mechanisms associated with salt stress and identify genes of potential importance in cultivated chrysanthemum, we carried out transcriptome sequencing of chrysanthemum. Two cDNA libraries were generated from the control and salt-treated samples (Sample_0510_control and Sample_0510_treat) of leaves. By using the Illumina Solexa RNA sequencing technology, 94 million high quality sequencing reads and 161,522 unigenes were generated and then we annotated unigenes through comparing these sequences to diverse protein databases. A total of 126,646 differentially expressed transcripts (DETs) were identified in leaf. Plant hormones, amino acid metabolism, photosynthesis and secondary metabolism were all changed under salt stress after the complete list of GO term and KEGG enrichment analysis. The hormone biosynthesis changing and oxidative hurt decreasing appeared to be significantly related to salt tolerance of chrysanthemum. Important protein kinases and major transcription factor families involved in abiotic stress were differentially expressed, such as MAPKs, CDPKs, MYB, WRKY, AP2 and HD-zip. In general, these results can help us to confirm the molecular regulation mechanism and also provide us a comprehensive resource of chrysanthemum under salt stress.

盐胁迫（salt stress）对菊花的生长与产量具有显著影响。为解析与盐胁迫相关的分子机制，并筛选栽培菊花中具有潜在应用价值的功能基因，本研究开展了菊花转录组测序工作。本研究从叶片对照与盐处理样本（Sample_0510_control与Sample_0510_treat）中构建了两份cDNA文库。借助Illumina Solexa RNA测序技术，共获得9400万条高质量测序读段与161522条unigene（非冗余基因序列）；随后通过将上述序列与多种蛋白质数据库进行比对，完成了unigene的注释工作。本研究在叶片样本中共鉴定得到126646条差异表达转录本（differentially expressed transcripts, DETs）。通过对基因本体论（Gene Ontology, GO）条目与京都基因与基因组百科全书（Kyoto Encyclopedia of Genes and Genomes, KEGG）富集分析结果的全面梳理，发现盐胁迫下植物激素、氨基酸代谢、光合作用以及次生代谢通路均发生显著改变。激素生物合成通路的调控变化与氧化损伤的缓解，似乎与菊花的耐盐性显著相关。参与非生物胁迫响应的关键蛋白激酶家族与主要转录因子家族均呈现差异表达，包括丝裂原活化蛋白激酶（mitogen-activated protein kinases, MAPKs）、钙依赖蛋白激酶（calcium-dependent protein kinases, CDPKs）、MYB、WRKY、AP2以及同源域-亮氨酸拉链（HD-zip）。综上，本研究结果不仅有助于阐明菊花响应盐胁迫的分子调控机制，同时也为盐胁迫下的菊花研究提供了一套全面的组学数据资源。