表达SmERF1调节烟草种子大小及耐盐性

Expression of SmERF1 in tobacco improves plant salinity tolerance and regulates seed size

【目的】ERF转录因子生物功能广泛,在调控植物生长发育和响应胁迫中发挥重要作用。前期研究显示,丹参SmERF1参与植物响应胁迫反应。该研究旨在进一步明确SmERF1潜在的生物功能,并为药用植物抗性及种子发育研究奠定基础。【方法】该研究采用农杆菌介导的方法在模式植物烟草中异源表达了丹参SmERF1基因;通过抗性相关酶活性变化检测,对转基因植株抗性进行评价;通过酶联免疫方法和qPCR方法分析GA和ABA等激素含量及合成途径关键酶基因的表达变化。【结果】(1)表达SmERF1的烟草植株在幼苗期表现出生长缓慢、生物量和叶绿素减少,而在其他生长阶段与对照植株没有明显差异;此外,表达SmERF1的烟草植株种子比野生对照的种子小、轻;(2)在盐处理下,转基因烟草株系中脯氨酸含量、SOD和POD活性高于对照株系,而MDA含量低于对照株系,转基因烟草株系表现出较高的耐盐性;(3)在转烟草株系中,ABA含量上调,GA水平降低。实时定量PCR结果显示,表达SmERF1调节了与植物激素生物合成相关的关键酶基因的表达,如NtSDR、NtGA20ox、NtACO和NtACS。【结论】SmERF1通过ABA依赖途径增强了烟草对盐胁迫的耐受性,并调控种子大小。

[Objective]The transcription factor ERF has various biological functions,and plays important roles in regulating plant growth,development and responding to stress.Previous studies have shown that SmERF1 from Salvia miltiorrhiza was involved in plant response to stress.This study aimed to further elucidate the potential function of SmERF1 and lay a foundation for the study of resistance and seed development of medicinal plants.[Methods]SmERF1 was heterologously expressed in the model plant tobacco mediated by Agrobacterium tumefaciens in this study.The resistance of transgenic plants was evaluated through determining the plant resistance-related enzyme activities.The levels of hormones such as GA and ABA were analyzed using enzyme-linked immunosorbent assays,and the expression of key enzyme genes involved in hormone biosynthesis were detected with qPCR methods.[Results](1)SmERF1-expressing tobacco plants showed slower growth,less biomass,and decrease in chlorophyll at the seedling stage,with no significant difference in other growth stages.In addition,seeds of tobacco plants expressing SmERF1 genes were smaller and lighter than those of wild plants.(2)Under NaCl treatment,the transgenic tobacco lines showed better tolerance to salinity,and the proline content,SOD and POD activities of transgenic lines were higher than those of wild type plants,while MDA content was lower than that of wild-type plants.(3)We determined the phytohormones related to plant resistance,and the results showed that transgenic tobacco plants had higher ABA levels but lower GA levels compared with wild type plants.The expression of SmERF1 regulated the expression of the key enzyme genes related to plant hormone biosynthesis,such as NtSDR,NtGA20ox,NtACO,and NtACS.[Conclusion]SmERF1 enhances tobacco tolerance to salt stress and may regulate seed size through the ABA-dependent pathway.