Transformation of sugar beet with genes conferring tolerance against biotic stresses might accelerate improvement of new hybrid varieties with respect to root yield. In the present study, the optimization of transformation procedure and the integration of four agronomically important genes were assessed in two sugar beet inbred lines. First, the transformation system was optimized with the Agrobacterium tumefacienes LBA4404 and GV3101 strains harboring a recombinant plasmid vector. The vector was constructed based on pBI121 plasmid containing the cryIA105, cryIIIAa, CP4‐epsps and gox genes. The effects of four factors including the strains and growth density of Agrobacterium, inoculation time, and plant lines on the frequency of regeneration were assessed. The adventitious bud excised leaflets were used as explants for tissue culture. A factorial experiment based on completely randomized design was adopted as statistical model. Analysis of variance showed that simple effect of Agrobacterium strain, growth density and inoculation time on regeneration of transgenic plantlets, as well as growth rate × inoculation time interaction had significant effects on regeneration of transgenic plantlets. Means comparison analyses indicated that OD₆₀₀ = 0.6 and inoculation time of 15 min were the best conditions for transformation. Totally, more than 330 putative transgenic plantlets were regenerated during transformation. The presence of transgenes in the putative transgenic plants was confirmed by polymerase chain reaction (PCR) analysis. Subsequently, transcription of transgenes was confirmed by Reverse Transcription‐PCR analysis. Overall, our results revealed that the modified protocol for transformation could be used successfully to introduce new gene cassettes into sugar beet lines.

中文翻译：

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农杆菌介导的甜菜转化的优化：草甘膦和害虫抗性相关基因

用赋予对生物胁迫耐性的基因转化甜菜可能会加速新杂交品种根系产量的提高。在本研究中，在两个甜菜近交系中评估了转化程序的优化和四个农学上重要基因的整合。首先，用携带重组质粒载体的土壤杆菌农杆菌LBA4404和GV3101菌株优化转化系统。该载体是基于质粒的pBI121含有构建哭IA105，哭IIIAA，CP4- EPSPS和GOX的基因。农杆菌的菌株和生长密度这四个因素的影响，接种时间和植物株系的再生频率进行了评估。不定芽切下的小叶用作组织培养的外植体。采用基于完全随机设计的析因实验作为统计模型。方差分析表明，农杆菌菌株，生长密度和接种时间对转基因小植株再生的简单影响，以及生长速度×接种时间的相互作用对转基因小植株的再生有显着影响。均值比较分析表明OD ₆₀₀ = 0.6和15分钟的接种时间是转化的最佳条件。总共在转化过程中再生了330多个推定的转基因幼苗。通过聚合酶链反应（PCR）分析证实推定的转基因植物中转基因的存在。随后，通过逆转录-PCR分析确认了转基因的转录。总的来说，我们的结果表明，改良的转化方案可以成功地用于将新的基因盒引入甜菜品系。