Ethylene response factors (ERFs) are unique to plants and play crucial roles in their response to various biotic and abiotic stresses, but the physiological and molecular mechanisms accounting for the functions of many ERF genes in abiotic stress are not well characterized in tomato. Here, an ERF gene, SlERF.B1 was characterized, which belongs to the IX subfamily of ERFs. SlERF.B1 expression was induced by salt, mannitol, cold, heat and ACC treatments, but repressed by ABA, IAA and 1-MCP treatments. The SlERF.B1 protein was nuclear-localized in tobacco and had no transcription activity in yeast. SlERF.B1-overexpression transgenic tomato and Arabidopsis exhibited significantly high sensitivity to salt treatment compared to wild-type at the phenotypic and physiological levels. Similarly, SlERF.B1-overexpression tomato plants exhibited lower tolerance to mannitol and drought stresses. Transcriptional analysis showed that transcript levels of several stress-responsive genes in SlERF.B1-overexpression lines were significantly inhibited under salt and drought stresses. Additionally, SlERF.B1 could repress SlARF5 (Auxin response factor 5) and SlER24 (ethylene-responsive transcriptional coactivator/Multiprotein bridging factor 1) expressions by binding to dehydration-responsive element (DRE) in the promoters. Overall, the current results suggest that SlERF.B1 functions as a negative regulator of osmotic resistance.

乙烯响应因子 (ERFs) 是植物独有的，在它们对各种生物和非生物胁迫的响应中发挥着至关重要的作用，但在番茄中，许多ERF基因在非生物胁迫中的功能的生理和分子机制尚未得到很好的表征。在这里，表征了ERF基因SlERF.B1，它属于ERF的IX亚家族。SlERF.B1表达被盐、甘露醇、冷、热和 ACC 处理诱导，但被 ABA、IAA 和 1-MCP 处理抑制。SlERF.B1 蛋白定位于烟草中，在酵母中没有转录活性。SlERF.B1-过表达转基因番茄和拟南芥与野生型相比，在表型和生理水平上对盐处理表现出显着的高敏感性。同样，SlERF.B1-过表达的番茄植株对甘露醇和干旱胁迫的耐受性较低。转录分析表明，在盐和干旱胁迫下， SlERF.B1过表达系中几个应激反应基因的转录水平受到显着抑制。此外，SlERF.B1 可以抑制SlARF5（生长素反应因子 5）和SlER24(乙烯反应性转录共激活因子/多蛋白桥接因子 1) 通过与启动子中的脱水反应元件 (DRE) 结合来表达。总体而言，目前的结果表明 SlERF.B1 作为渗透阻力的负调节剂。