大花美人蕉遗传转化体系研究

Research on the genetic transformation system of Canna×generalis

  • 摘要:目的】建立农杆菌介导的大花美人蕉遗传转化体系,为进一步开展大花美人蕉的基因功能研究及转基因育种提供参考依据。【方法】以大花美人蕉墨红的胚性愈伤组织为受体材料,分别接种于含不同浓度卡那霉素(Kan)(0、20、40、60、80和100 mg/L)和头孢噻肟(Cef)(0、100、300、500和600 mg/L)的MS培养基中进行培养,筛选抗生素和抑菌剂的最适浓度。采用正交试验探究预培养时间(0、1、2和3 d)、菌液浓度(OD600 nm)(0.3、0.4、0.5和0.6)、侵染时间(8、10、12和15 min)、共培养时间(1、2、3和4 d)和乙酰丁香酮(AS)浓度(0、100、150和200 μmol/L)共16个组合对大花美人蕉遗传转化效率的影响,筛选大花美人蕉遗传转化的最适条件,并随机选取8株阳性美人蕉植株进行PCR鉴定。【结果】大花美人蕉愈伤组织对Kan和Cef均较为敏感,当Kan浓度升高至80 mg/L时,30 d后愈伤组织的成活率为15.00%,且多呈褐色并死亡,极少增殖,80 mg/L为培养大花美人蕉愈伤组织的最适Kan浓度;当Cef浓度为300 mg/L时,培养30 d后愈伤组织的成活率为26.67%,且愈伤组织生长增殖状态良好,部分愈伤组织能够形成出芽,300 mg/L为大花美人蕉愈伤组织的最适Cef浓度。正交试验分析结果显示,预培养1 d、OD600 nm为0.3、AS浓度100 μmol/L、侵染12 min及共培养4 d时,愈伤组织和芽的阳性转化率最高,分别为38.00%和12.16%,显著高于除组合4和组合8之外的其他组合(P<0.05);菌液浓度和预培养时间分别是影响阳性愈伤组织转化率和阳性芽转化率的主要因子。8株阳性美人蕉植株中,6株阳性植株均在843 bp处有清晰的目的条带,证明外源基因eGFP在这6株美人蕉阳性植株中表达成功。【结论】成功建立了农杆菌介导的大花美人蕉遗传转化体系,筛选出大花美人蕉遗传转化的最适条件为预培养1 d、OD600 nm=0.3、AS浓度100 μmol/L、侵染12 min及共培养4 d。

     

    Abstract:Objective】This study aimed to establish an Agrobacterium-mediated genetic transformation system for Canna×generalis, providing a reference for further study of gene function study and transgenic breeding of Canna×generalis.【Method】Using the embryogenic callus of the Canna×generalis Bailey. ‘Mohong’ as the recipient material, the calli were inoculated into MS medium containing different concentrations of kanamycin (Kan) (0, 20, 40, 60, 80, and 100 mg/L) and cefotaxime (Cef) (0, 100, 300, 500, and 600 mg/L), and they were then cultured to screen the optimal concentrations of antibiotics and antimicrobial agents. The orthogonal experiments were conducted to investigate the effects of 16 combinations, including pre-culture duration (0, 1, 2, and 3 d), microbial liquid concentration (OD600 nm) (0.3, 0.4, 0.5, and 0.6), infection duration (8, 10, 12, and 15 min), co-culture duration (1, 2, 3, and 4 d) and acetosyringone (AS) concentration (0, 100, 150, and 200 μmol/L), on the genetic transformation efficiency of Canna×generalis. The optimal conditions for genetic transformation were identified, and eight positive Canna plants were randomly selected for PCR detection.【Result】The Canna×generalis calli were relatively sensitive to Kan and Cef: when the Kan concentration increased to 80 mg/L, the survival rate of calli after 30 d of culture was 15.00%, and most of them turned brown and died alongside little proliferation, indicating the optimal Kan concentration for culturing Canna×generalis calli was 80 mg/L; at a Cef concentration of 300 mg/L, the survival rate of calli after 30 d of culture was 26.67%, and the calli exhibited vigorous growth and proliferation, with some calli capable of budding, indicating the optimal Cef concentration for culturing Canna×generalis calli was 300 mg/L. Orthogonal experiment analysis revealed that, under the conditions of pre-culture for 1 d, OD600nm of 0.3, AS concentration of 100 μmol/L, 12 min of infection, and co-culture for 4 d, the highest positive transformation rates for calli (38.00%) and buds (12.16%) were achieved, which were significantly higher than those of other combinations except for Combination 4 and Combination 8 (P<0.05). Bacterial liquid concentration and pre-culture duration were the primary factors affecting the transformation rates of positive callus and positive bud, respectively. Among the eight positive Canna plants, six exhibited distinct target bands at 843 bp, confirming successful expression of the exogenous eGFP gene in these six positive Canna plants.【Conclusion】An Agrobacterium-mediated genetic transformation system for Canna×generalis is successfully established, and the optimal conditions for the genetic transformation are pre-culture for 1 d, OD600=0.3, AS concentration of 100 μmol/L, infection for 12 min, and co-culture for 4 d.

     

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