紫花苜蓿高频体胚发生及萌发成苗技术与转基因应用

以紫花苜蓿的子叶或叶片为外植体,建立高频体胚发生及成苗技术体系,为苜蓿耐逆性状的遗传改良提供技术支撑。在愈伤诱导、体胚诱导、体胚成熟与萌发等几个关键环节,分析比较培养基组分对培养效果的影响。建立在SHDK培养基上诱导愈伤、MB(-/+)+ABA 0.4mg/L+PEG-6000 50g/L+蔗糖50g/L培养基上诱导体胚、Bio2Y培养基上促体胚发育成熟、1/2 MS(或SH)培养基上体胚萌发成苗的高频再生技术体系。最适条件下,每克胚性愈伤组织可产生77.9个正常萌发成苗的健康体胚。再生植株在生长箱内经过2周20℃、16h/d的光照培养后移栽温室,成活率达90%以上。利用该离体再生技术成功地将凝集素基因PPA导入苜蓿中,获得抗蚜转基因苜蓿。

High Frequency of Embryogenesis and Germination to Seedling in Alfalfa and Its Application in Transgenic Research

The objective of this study was to establish the technique for high efficient embryogenesis and seedling development using cotyledons or leaves from aseptic seedlings as explants,which will provide a technical support for genetic improvement of tolerance to abiotic stresses in alfalfa(Medicago sativa).The effects of different medium ingredients on callus induction,embryogenetic induction,maturation,and germination were compared.The technique for high-frequency of embryogenesis included induction of callus on SHDK medium,induction of embyros on MB(-/+) + 0.4 mg/L ABA+50 g/L PEG-6000+50 g/L sucrose,growth of embryos on Bio2Y medium,and development of seedling on 1/2 MS(or SH) medium.Under the optimal conditions,about 77.9 healthy embryos that formed seedlings were produced per gram of callus.The seedlings regenerated were grown in a growth chamber at 20 °C with a photoperiod of 16 h light and 8 h dark for two weeks prior to transplanting to a greenhouse,and the survival rate was over 90%.This technique was successfully used in the transformation of PPA gene into alfalfa and the transgenic alfalfa with resistance to aphid was obtained.