Study On Transformation Of Visual Marker Gene And Regeneration Of Onion

Onion is one of the most important vegetable crops in the world, there is high healthcare value. The nutritional quality is always the main goal of the onion breeding, The development of genetic engineering provide a new way for onion breeding, it can overcome the problem that conventional plant breeding is unable to solve, such as agronomic traits improvement and environmental adaptation, it is an effective methods of molecular breeding to modify plant traits, breeding new varieties. This study uses onion germ as explant materials to establish regeneration system, and on this basis, the anthocyanin synthesis gene transcription factor (Bi and C1) was transformed into onions callus, the transgenic plants was obtained by analysis of PCR, glyphosate resistance screening and the gene expression, this study is mainly to obtain the following results:1. The onion regeneration system using the onion germ as the explants was established in MS medium supplemented with different plant growth regulator. The results showed that MS+4mg/L2,4-D+1mg/L6-BA was the most suitable for callus induction, the induction frequency of primary callus was72.1%. The induction frequency of embryogenic callus reached72.8%in MS medium supplemented with2mg/L2,4-D+2mg/L6-BA+5mg/L AgNO3. Compared four different varieties of onion on the same conditions, the induction frequency of primary callus were significantly different. The addition of1mg/L TDZ+0.5mg/L N AA+7.5mg/L AgNO3increased the frequency of embryogenic callus formation(82.7%). Shoot regeneration was completely inhibited by1.0mg/L glyphosate. The regenerated plantlets were transferred to1/2MS medium supplemented with0.01mg/L NAA for root development, the frequency of root formation was100%. The regenerated plantlets transplanting survival rate reached95%. Glyphosate lethal concentration was0.5%o for onion seedling.2. Anthocyanin biosynthesis transcription factor gene (Bi and Cl) was transformed into the onion epidermal by gene gun, some cells’ color turned purple, It was proved that pBAC9075can be normal operation in onion epidermal cells. The vector of pBAC9075was transformed into onion callus by Agrobacterium tumefaciens mediated method, after glyphosate screening,189isolates were obtained from renewable plants, PCR assay showed that there are5positive plants,2positive plants have anthocyanin accumulation of the bulb. The above results provide a basis for anthocyanin which using as a visual tracking system used for the early screening of transgenic plants.