Eucalyptus are widely cultivated in several regions of the world due to their adaptability to different climatic conditions and amenable to tree breeding programs. With changes in environmental conditions pointing to an increase in aridity in many areas of the globe, the demand for genetic materials that adapt to this situation is required. Therefore, the aim of this work was to identify contrasting differences between two Eucalyptus species under water stress through the identification of differentially abundant proteins. For this, total protein extraction was proceeded from leaves of both species maintained at 40 and 80% of field capacity (FC). The 80% FC water regime was considered as the control and the 40% FC, severe water stress. The proteins were separated by 2-DE with subsequent identification of those differentially abundant by liquid nanocromatography coupled to high resolution MS (Q-Exactive). Comparative proteomics allowed to identify four proteins (ATP synthase gamma and alpha, glutamine synthetase and a vacuolar protein) that were more abundant in drought-tolerant species and simultaneously less abundant or unchanged in the drought- sensitive species, an uncharacterized protein found exclusively in plants under drought stress and also 10 proteins (plastid-lipid, ruBisCO activase, ruBisCO, protease ClpA, transketolase, isoflavone reductase, ferredoxin-NADP reductase, malate dehydrogenase, aminobutyrate transaminase and sedoheptulose-1-bisphosphatase) induced exclusively in the drought-tolerant species in response to water stress. These results suggest that such proteins may play a crucial role as potential markers of water stress tolerance through the identification of species-specific proteins, and future targets for genetic engineering.

桉树由于对不同气候条件的适应性强并且适合于树木育种计划，因此在世界上多个地区被广泛种植。随着环境条件的变化表明全球许多地区的干旱都在增加，因此需要对适应这种情况的遗传材料的需求。因此，这项工作的目的是确定两种桉树之间的对比差异。通过鉴定差异丰富的蛋白质鉴定水分胁迫下的物种。为此，从两个物种的叶片中进行总蛋白提取，保持其田间持水量（FC）的40％和80％。80％FC的水分状况被认为是对照，而40％FC则被认为是严重的水分胁迫。通过2-DE分离蛋白质，随后通过与高分辨率MS（Q-Exactive）耦合的液体纳米色谱法鉴定差异丰富的蛋白质。比较蛋白质组学可以鉴定四种蛋白（ATP合酶γ和α，谷氨酰胺合成酶和液泡蛋白），它们在耐旱物种中含量较高，而在对干旱敏感的物种中含量较低或不变，这是一种仅在植物中发现的未表征的蛋白质在干旱胁迫下还有10种蛋白质（质体脂质，ruBisCO激活酶，ruBisCO，蛋白酶ClpA，转酮醇酶，异黄酮还原酶，铁氧还蛋白-NADP还原酶，苹果酸脱氢酶，氨基丁酸转氨酶和sedoheptulose-1-双磷酸酶是在干旱胁迫下响应水分胁迫而专门诱导的。这些结果表明，通过鉴定物种特异性蛋白质以及基因工程的未来目标，此类蛋白质可能起着至关重要的作用，成为潜在的耐水胁迫标志物。