根据麻疯树pepc基因和植物表达载体的酶切位点特征,分别将pepc基因全长序列3 000 bp正向插入pCAMBIA2300,构建了正义表达载体pCAMBIA-Jcpepc,基因片段597 bp反向插入pBI121构建了反义表达载体pBI-Jcpepc。通过农杆菌介导,采用叶盘法转化烟草,通过对转基因植株的PCR和PCR-Southern检测,表明pepc基因已经正向、反向插入烟草基因组中。测定了转基因烟草的PEPCase酶活性,并通过脂肪酸的测定,转正义pepc基因烟草叶片的脂肪酸含量平均比对照降低44.3%,转反义pepc基因植株脂肪酸含量平均比对照增加26.3%。

Agrobacteriurn tumefaciens-mediated transformation (AtMT) method was used to study the genetic transformation in Rhizopus arrhizus of antisense expression vector pBI121-fad2 of VeFAD2 gene. We studied the key factors influencing transformation, such as A.tumefaciens strains,bacterial cell volume initially used, co-cultivation time, effective period and concentration of AS. The results shows that the ideal A.tumefaciens strain is AGL-1, the optimum bacterial cell volume initially used is 50-100 μL and co-culture 24 hours will get the most transformants. At co-culture period, AS induction is indispensable. It is beneficial to improve transformation ratio by adding to 200 μmol·L-1 AS at preincubate period and increasing AS concentration to 400-600 μmol·L-1 at co-culture period. It determined that antisense VeFAD2 gene has been integrated into the genome of R. arrhizus by PCR-Southern detection.

The effects of physical and chemical factors on the property of the mulberry pigment were studied. The results show that the light and heat affect the stability of the mulberry pigment. The pigment is stable with lower pH, but the color changes at weak acid level which is close to neutrality. The pigment has less resistance capability against oxidizing or reducing agent and it is sensitive to chelating agent or sodium benzoate. Glucose and sucrose have little effects on the pigment, but salt, citric acid or vitamin C can enforce the color of the pigment. Metal ions Co2+, Cu2+, Mg2+, Ca2+, Zn2+, Mn2+, K+, A13+, Sn2+ can strengthen the color, but Fe2+, Fe3+, and Pb2+ weaken the stability of the pigment.