Improved drought and salt stress tolerance in transgenic tobacco overexpressing a novel A20/AN1 zinc-finger "AlSAP" gene isolated from the halophyte grass Aeluropus littoralis
Improved drought and salt stress tolerance in transgenic tobacco overexpressing a novel A20/AN1 zinc-finger "AlSAP" gene isolated from the halophyte grass Aeluropus littoralis
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DOI：
10.1007/s11103-009-9560-4
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发表时间：
2010-01-01
影响因子：
5.1
通讯作者：
Hassairi, Afif
中科院分区：
文献类型：
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作者：
Ben Saad, Rania;Zouari, Nabil;Hassairi, Afif
在这里，我们描述了一个新基因的分离，命名为alSAP，在第一步，开发这种盐生植物草作为遗传资源的潜力，以提高植物，特别是在谷物中的耐盐性和抗旱性。Aeluropus基因组只有一个AlSAP基因，其5‘端非编码区有一个内含子。序列同源性分析表明，AlSAP蛋白含有两个保守的锌指结构域A20和AN1。AlSAP不仅受到盐、渗透、热、冷等非生物胁迫的诱导，还受到脱落酸(ABA)和水杨酸(SA)的诱导。在CaMV35S启动子的控制下，表达AlSAP基因的烟草植株对盐分(350 MM NaC L)、干旱(土壤相对含水量=25%)、高温(55摄氏度，2.5 h)和冰冻(-20摄氏度，3 h)等非生物胁迫的耐受性增强。此外，在高盐和干旱条件下，转基因植物能够完成它们的生活史，并产生可存活的种子，而野生型植物在营养阶段死亡。与野生型烟草相比，转AlSAP基因烟草株系叶片RWC、根系和叶片内源Na+、K+含量的测定结果表明，与野生型烟草相比，其衰老基生叶的失水率明显降低，Na+积累量增加。最后，我们发现AlSAP转基因烟草中8个逆境相关基因的转录水平高于野生型烟草。综上所述，这些结果表明，AlSAP是一个在栽培植物耐旱性和耐盐性工程中有潜在应用价值的候选基因。
We describe here the isolation of a novel gene, designated AlSAP, from A. littoralis in a first step to exploit the potential of this halophyte grass as a genetic resource to improve salt and drought tolerance in plants and, particularly, in cereals. The Aeluropus genome contains a single AlSAP gene which has an intron at its 5'UTR. Sequence homology analysis showed that the AlSAP protein is characterized by the presence of two conserved zinc-finger domains A20 and AN1. AlSAP is induced not only by various abiotic stresses such as salt, osmotic, heat and cold but, also by abscisic acid (ABA) and salicylic acid (SA). Tobacco plants expressing the AlSAP gene under the control of the duplicated CaMV35S promoter exhibited an enhanced tolerance to abiotic stresses such as salinity (350 mM NaCl), drought (soil Relative Water Content (RWC) = 25%), heat (55A degrees C for 2.5 h) and freezing (-20A degrees C for 3 h). Moreover, under high salt and drought conditions, the transgenic plants were able to complete their life cycle and to produce viable seeds while the wild-type plants died at the vegetative stage. Measurements of the leaf RWC and of the root and leaf endogenous Na+ and K+ levels in AlSAP transgenic lines compared to wild-type tobacco, showed an evident lower water loss rate and a higher Na+ accumulation in senescent-basal leaves, respectively. Finally, we found that the steady state levels of transcripts of eight stress-related genes were higher in AlSAP transgenic lines than in wild-type tobacco. Taken together, these results show that AlSAP is a potentially useful candidate gene for engineering drought and salt tolerance in cultivated plants.