Brosché Mikael, Vinocur Basia, Alatalo Edward R, Lamminmäki Airi, Teichmann Thomas, Ottow Eric A, Djilianov Dimitar, Afif Dany, Bogeat-Triboulot Marie-Béatrice, Altman Arie, Polle Andrea, Dreyer Erwin, Rudd Stephen, Paulin Lars, Auvinen Petri, Kangasjärvi Jaakko
Plant Biology, Department of Biological and Environmental Sciences, University of Helsinki, P,O, Box 65, Viikinkaari 1, FIN-00014 Helsinki, Finland.
Genome Biol. 2005;6(12):R101. doi: 10.1186/gb-2005-6-12-r101. Epub 2005 Dec 2.
Plants growing in their natural habitat represent a valuable resource for elucidating mechanisms of acclimation to environmental constraints. Populus euphratica is a salt-tolerant tree species growing in saline semi-arid areas. To identify genes involved in abiotic stress responses under natural conditions we constructed several normalized and subtracted cDNA libraries from control, stress-exposed and desert-grown P. euphratica trees. In addition, we identified several metabolites in desert-grown P. euphratica trees.
About 14,000 expressed sequence tag (EST) sequences were obtained with a good representation of genes putatively involved in resistance and tolerance to salt and other abiotic stresses. A P. euphratica DNA microarray with a uni-gene set of ESTs representing approximately 6,340 different genes was constructed. The microarray was used to study gene expression in adult P. euphratica trees growing in the desert canyon of Ein Avdat in Israel. In parallel, 22 selected metabolites were profiled in the same trees.
Of the obtained ESTs, 98% were found in the sequenced P. trichocarpa genome and 74% in other Populus EST collections. This implies that the P. euphratica genome does not contain different genes per se, but that regulation of gene expression might be different and that P. euphratica expresses a different set of genes that contribute to adaptation to saline growth conditions. Also, all of the five measured amino acids show increased levels in trees growing in the more saline soil.
生长在自然栖息地的植物是阐明适应环境限制机制的宝贵资源。胡杨是一种生长在盐碱半干旱地区的耐盐树种。为了鉴定自然条件下参与非生物胁迫反应的基因，我们从对照、受胁迫和沙漠生长的胡杨树上构建了几个标准化和扣除cDNA文库。此外，我们还鉴定了沙漠生长的胡杨树上的几种代谢产物。
获得了约14000个表达序列标签（EST）序列，很好地代表了可能参与抗盐和其他非生物胁迫的基因。构建了一个具有代表约6340个不同基因的单基因EST集的胡杨DNA微阵列。该微阵列用于研究生长在以色列艾因阿夫达特沙漠峡谷中的成年胡杨树上的基因表达。同时，对同一棵树上的22种选定代谢产物进行了分析。
在获得的EST中，98%在已测序的毛果杨基因组中发现，74%在其他杨树EST文库中发现。这意味着胡杨基因组本身并不包含不同的基因，而是基因表达的调控可能不同，并且胡杨表达了一组不同的基因，这些基因有助于适应盐碱生长条件。此外，所有测定的五种氨基酸在生长在盐分更高土壤中的树木中含量都有所增加。
