The response of a grass halophyte Spartina alterniflora at early stages of salt stress was investigated through generation and systematic analysis of expressed sequence tags (ESTs) from both leaf and root tissues. Random EST sequencing produced 1,227 quality ESTs, which were clustered into 127 contigs, and 368 were singletons. Of the 495 unigenes, 27% represented genes for stress response. Comparison of the 368 singletons against the Oryza sativa gene index showed that >85% of these genes had similarity with the rice unigenes. Moreover, the phylogenetic analysis of an EST similar to myo-inositol 1-phosphate synthase of Spartina and some selected grasses and halophytes showed closeness of Spartina with maize and rice. Transcript abundance analysis involving eight known genes of various metabolic pathways and nine transcription factor genes showed temporal and tissue-dependent variation in expression under salinity. Reverse northern analysis of a few selected unknown and ribosomal genes exhibited much higher abundance of transcripts in response to salt stress. The results provide evidence that, in addition to several unknown genes discovered in this study, genes involved in ion transport, osmolyte production, and house-keeping functions may play an important role in the primary responses to salt stress in this grass halophyte.

中文翻译：

---

盐生植物、光滑的禾本科植物（Spartina alterniflora Loisel.）对盐胁迫的主要反应。

通过叶和根组织表达序列标签 (EST) 的生成和系统分析，研究了盐生植物互花米草在盐胁迫早期的反应。随机 EST 测序产生了 1,227 个质量 EST，它们聚集成 127 个重叠群，其中 368 个是单例。在 495 个 unigenes 中，27% 代表应激反应基因。将 368 个单子与水稻基因指数进行比较表明，这些基因中有 >85% 与水稻 unigenes 具有相似性。此外，与麦草和一些选定的草和盐生植物的肌醇 1-磷酸合酶相似的 EST 的系统发育分析表明麦草与玉米和水稻的亲缘关系。涉及各种代谢途径的八个已知基因和九个转录因子基因的转录丰度分析显示盐度下表达的时间和组织依赖性变化。一些选定的未知基因和核糖体基因的反向北向分析显示出更高丰度的转录本以响应盐胁迫。结果提供的证据表明，除了本研究中发现的几个未知基因外，参与离子转运、渗透质产生和管家功能的基因可能在这种草盐生植物对盐胁迫的初级反应中发挥重要作用。