The ubiquitin/26S proteasome pathway is widely related to plant growth and metabolism and response to treatment by specifically degrading ubiquitin-modified proteins, including RING-finger-type E3 ubiquitin ligase (RING). The RING finger protein (RFP) gene family, determining the specificity of the ubiquitination process, is numerous and complex in function. In this study, we constructed a pCEGFP-StRFP2 fusion protein expression vector and transformed it into tobacco to achieve transient expression, thereby confirming that StRFP2 is localized in the cell membrane and cytoplasm. The result of qRT-PCR analysis showed that StRFP2 gene was significantly expressed in potato leaves, and the expression level of StRFP2 was significantly up-regulated under drought treatment. The transgenic plants of overexpressing StRFP2 gene were obtained with Agrobacterium tumefaciens-mediated transformation. Plant height, stem diameter, root length, fresh weight and root-shoot ratio of transgenic plants were significantly higher than those of non-transgenic plants (WT), indicating that the growth of plants was significantly promoted after overexpression of StRFP2 gene. Under PEG osmotic stress, the expressional level of StRFP2 in transgenic potato plants was significantly higher than that of WT. Furthermore, the free proline content and CAT activity in transgenic plants were higher than WT, on the contrary, MDA was lower than WT, and transgenic plants have stronger water retention capacity under simulated drought stress treatment, which indicated that StRFP2 could strengthen the tolerance of plants responding to drought stress. The above evidence strongly suggested that the StRFP2 gene is obviously up-regulated expression by drought stress, thereby enhancing the drought tolerance of the potato.

中文翻译：

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马铃薯的RING手指蛋白基因StRFP2与耐旱性有关。

泛素/ 26S蛋白酶体途径与植物生长和代谢以及通过特异性降解包括RING-手指型E3泛素连接酶（RING）在内的泛素修饰的蛋白质而对治疗的反应广泛相关。决定泛素化过程特异性的RING手指蛋白（RFP）基因家族功能众多且复杂。在这项研究中，我们构建了pCEGFP-StRFP2融合蛋白表达载体，并将其转化到烟草中以实现瞬时表达，从而证实StRFP2位于细胞膜和细胞质中。qRT-PCR分析的结果表明，干旱条件下StRFP2基因在马铃薯叶片中表达明显，并且StRFP2的表达水平明显升高。通过根癌农杆菌介导的转化获得了过量表达StRFP2基因的转基因植物。转基因植物的株高，茎粗，根长，鲜重和根冠比均显着高于非转基因植物，表明StRFP2基因过表达后植物的生长得到显着促进。在PEG渗透胁迫下，转基因马铃薯植株中StRFP2的表达水平明显高于野生型。此外，转基因植物中游离脯氨酸的含量和CAT活性均高于野生型，而MDA低于野生型，转基因植物在模拟干旱胁迫下的保水能力较强，表明StRFP2可以增强转基因植株的耐性。植物应对干旱胁迫。