背景:细胞膜是动态结构,不断调整他们的组成,允许植物对发育信号做出反应,强调,和不断变化的环境。为了促进底物的跨膜运输,植物膜嵌入了主动和被动转运蛋白。水通道蛋白(AQP)构成跨膜通道蛋白的主要家族,其选择性地促进底物以惊人的每秒108个分子穿过生物膜的被动双向通道。AQP是植物界中最多样化的,由五个在时间和空间基因表达上不同的主要亚家族组成,亚细胞蛋白定位,底物特异性,和翻译后调节机制;共同提供跨越整个工厂的动态运输网络。植物AQP可以运输多种植物过程所必需的溶质,包括,水关系,成长和发展,应激反应,根系养分吸收,和光合作用。操纵AQPs以提高植物生产力的能力,依赖于扩大我们对AQP的多样性和功能角色的洞察力。
结果:我们表征了烟草的AQP家族(NtAQPs;烟草),一种流行的模型系统,能够从实验室扩展到现场。烟草与主要经济作物(如番茄、马铃薯,茄子和辣椒),本身也有新的商业应用。烟草拥有76个AQP,使其成为第二大AQP家族。它们分为五个不同的亚科,我们描述了系统发育关系,基因结构,蛋白质序列,选择性过滤成分,亚细胞定位,和组织特异性表达。我们还从烟草的亲本基因组中鉴定了AQP(N。sylvestrisandN.tomentosiformis),使我们能够描述NtAQP家族的进化史。将正交性分配给番茄和马铃薯AQPs,可以进行蛋白质结构保守性的跨物种比较,基因表达,和潜在的生理角色。
结论:这项研究提供了烟草AQP家族的全面特征,加强当前对AQP生物学的认识。精制的基因/蛋白质模型,组织特异性表达分析,和跨物种比较,为NtAQPs及其茄科直系同源物的进化史和可能的生理作用提供有价值的见解。总的来说,这些结果将支持未来的功能研究,并有助于将基础研究转移到应用农业。
BACKGROUND: Cellular membranes are dynamic structures, continuously adjusting their composition, allowing plants to respond to developmental signals, stresses, and changing environments. To facilitate transmembrane transport of substrates, plant membranes are embedded with both active and passive transporters. Aquaporins (AQPs) constitute a major family of membrane spanning channel proteins that selectively facilitate the passive bidirectional passage of substrates across biological membranes at an astonishing 108 molecules per second. AQPs are the most diversified in the plant kingdom, comprising of five major subfamilies that differ in temporal and spatial gene expression, subcellular protein localisation, substrate specificity, and post-translational regulatory mechanisms; collectively providing a dynamic transportation network spanning the entire plant. Plant AQPs can transport a range of solutes essential for numerous plant processes including, water relations, growth and development, stress responses, root nutrient uptake, and photosynthesis. The ability to manipulate AQPs towards improving plant productivity, is reliant on expanding our insight into the diversity and functional roles of AQPs.
RESULTS: We characterised the AQP family from Nicotiana tabacum (NtAQPs; tobacco), a popular model system capable of scaling from the laboratory to the field. Tobacco is closely related to major economic crops (e.g. tomato, potato, eggplant and peppers) and itself has new commercial applications. Tobacco harbours 76 AQPs making it the second largest characterised AQP family. These fall into five distinct subfamilies, for which we characterised phylogenetic relationships, gene structures, protein sequences, selectivity filter compositions, sub-cellular localisation, and tissue-specific expression. We also identified the AQPs from tobacco\'s parental genomes (N. sylvestris and N. tomentosiformis), allowing us to characterise the evolutionary history of the NtAQP family. Assigning orthology to tomato and potato AQPs allowed for cross-species comparisons of conservation in protein structures, gene expression, and potential physiological roles.
CONCLUSIONS: This study provides a comprehensive characterisation of the tobacco AQP family, and strengthens the current knowledge of AQP biology. The refined gene/protein models, tissue-specific expression analysis, and cross-species comparisons, provide valuable insight into the evolutionary history and likely physiological roles of NtAQPs and their Solanaceae orthologs. Collectively, these results will support future functional studies and help transfer basic research to applied agriculture.