Global transcriptome analysis of novel stress associated protein (<i>SAP</i>) genes expression dynamism of combined abiotic stresses in <i>Oryza sativa</i> (L.)

Genes encoding proteins with A20/AN1 zinc-finger domains, belonging to the stress associated protein (SAP) gene family, are present in all eukaryotes and play a decisive role in plant response to diverse physiological and molecular activities particularly on biotic and abiotic stresses (AbS). In this first and foremost study, global transcriptome analysis of members of the <i>SAP</i> gene family was carried out in C3 model-<i>Oryza sativa</i> (<i>OsSAP</i>) aiming at the identification of <i>OsSAP</i> genes activated in response to unique or Combined AbS (CAbS). Based on the available spatio-temporal and phytohormonal RNA-Seq expression profile datasets, nine <i>OsSAP</i> genes were filtered out and identified by a differential expression signature noted in various tissues as well as plant hormones. Comparative genome ideogram of <i>OsSAP</i> genes confirmed the orthologous collinearity with C4 panicoid genomes. Interactome of these genes, revealed the molecular cross-talks of <i>OsSAP</i>. Thus, the computational expression signature of <i>OsSAP</i> genes led to a better understanding of gene dynamism in diverse developmental tissues/organs. Transcriptional regulation analysis of key <i>OsSAP</i> genes in response to stress (drought and salinity) suggested the novel role of <i>OsSAP1</i>, <i>OsSAP2</i>, <i>OsSAP5, OsSAP7</i>, <i>OsSAP8</i> and <i>OsSAP11</i> in AbS. Altogether, the study provides deeper insights on molecular characteristics of <i>OsSAP</i> genes, which could be deployed further to decipher their precise functional roles in AbS responses. Communicated by Ramaswamy H. Sarma

编码带有A20/AN1锌指结构域（A20/AN1 zinc-finger domain）蛋白的基因，隶属于胁迫相关蛋白（stress associated protein, SAP）基因家族，广泛存在于所有真核生物中，在植物响应多种生理与分子活动，尤其是生物和非生物胁迫（biotic and abiotic stresses, AbS）的过程中发挥决定性作用。本项首创性研究以C3模式植物水稻（Oryza sativa）为研究对象，对其SAP基因家族成员开展全局转录组分析，旨在筛选出响应单一或联合非生物胁迫（Combined AbS, CAbS）的OsSAP基因。基于已公开的时空表达与植物激素处理下的RNA-Seq表达谱数据集，通过分析不同组织及植物激素处理下的差异表达特征，最终筛选并鉴定出9个OsSAP基因。对OsSAP基因开展的比较基因组染色体组型分析证实，其与C4黍型基因组存在直系同源共线性关系。对上述基因的相互作用组（interactome）分析，揭示了OsSAP基因间的分子交叉调控网络。综上，通过对OsSAP基因的计算表达特征分析，我们得以更深入理解其在不同发育组织/器官中的基因动态表达模式。对响应胁迫（干旱与盐胁迫）的关键OsSAP基因开展转录调控分析，结果表明OsSAP1、OsSAP2、OsSAP5、OsSAP7、OsSAP8及OsSAP11在生物和非生物胁迫中发挥全新的调控功能。本研究全面深入解析了OsSAP基因的分子特征，可为后续阐释其在生物和非生物胁迫响应中的精准功能角色提供重要支撑。本文由Ramaswamy H. Sarma供稿。