Optimization Experiments Of Agrobacterium-mediated Transformation In Potato And Evaluation Of Genotypes Responsive Ability

Potato is an important crop with vegetable and food uses.Its world production occupies at fourth place after rice,wheat and corn.China is the largest country of potato production in the world,but output per hectare was much lower than that of the United States and Holland and so on.The lack of excellent varieties and backward breeding methods are the main factors causing low potato yields.Among breeding methods,gene engineering breeding is an effective way.Up to now,though transformation in potato has been succeeded,it is far away from maturity.This study includes:(1)Evaluation of potato genotypes’ responsive abilities to genetic transformation.(2)Experiments of optimizing Agrobacterium-mediated transgenic system in potato,including four aspects:adding acetosyringone,adding surfactant Silwet L-77,using ultrasound and vacuum infiltration.We obtained the following results:1.Six of eight varieties tested(Ning 3、Ning 8、Yunshu 505、V0024-6、V0379-2、CV92028-1)generated resistant callus in culture medium containing HygB.The callus formation rates spreaded from 62.8%to 70.5%and Ning 8 gave the highest rate,indicating that the responsive abilities to genetic transformation change largely among different varieties.2.The addition of acetosyringone could significantly improve the transformation rate of potato,it grew up from 2.7%to 4.6%in "Desiree" with 100 μM acetosyringone treatment,and the optimum dosage of acetosyringone was between 100 μM-200 μM.3.Adding Silwet L-77 did not improve the transformation rate,and Silwet L-77 had poison effect on plants.The transformation rate began to decrease when the concentration of Silwet L-77 reached 0.01%.4.When treated with ultrasound,Agrobacterium blooms too heavy to inhibit its growth,causing the death of a large number of stems.So this method seems not to be suiTablele for potato genetic transformation.5.The vacuum infiltration treatment caused a certain damage to stems,and the vacuum treatment over 1 min can cause sharply decreases of callus formation rate and transformation rate.