| Glycine max(Linn.),the nutrients in soybean mainly include: high quality protein,plant fat,carbohydrate,vitamins and minerals.Soybean protein contains all the essential amino acids needed for human development,which is the best source of plant protein;the content of phospholipid in soybean fat is about 50%,which has the effects of protecting liver,strengthening brain and improving intelligence,beauty and beauty;soybean is rich in carbohydrates,in which dietary fiber can promote intestinal peristalsis,help the body to eliminate toxic substances,and reduce the consumption of some nutrients The occurrence of diseases;vitamins and minerals in soybean account for 4% ～ 5%,mainly B group and calcium.Although soybean contains many nutrients which are very beneficial to human body,it is often damaged by leaf eating pests in the process of soybean growth and development,which seriously affects the yield and quality of soybean.In China,ascotis selenaria schiffermuller et Denis,Monolepta nigrobilineata,Lygus pratensis and Prodenia litura fabridius are the main defoliating pests of soybean.Spodoptera litura is a kind of predatory and omnivorous pest.The newly hatched larvae feed on the mesophyll,leaving only the upper epidermis and veins of the leaves;after the 4th instar,they enter the stage of overeating.Spodoptera litura will continue to damage another field after eating all the crops in one field,causing extremely serious losses.For pest control,traditional chemical control methods can be used.However,long-term use of chemical fertilizers and pesticides will not only damage the ecological environment,but also make the pest resistant.Breeding transgenic insect resistant soybean plants through genetic engineering technology can effectively solve this series of problems.Genetic engineering technology refers to the introduction of functional trait genes such as disease resistance and insect resistance into target crops in vitro through scientific and technological means,so that the recipient plants can change the original genetic characteristics,obtain new functions,and produce new varieties.Bacillus thuringiensis(BT)is often used in the research of transgenic insect resistant crops,because it can produce insecticidal crystal proteins in the process of spore formation,(ICPs)are not bioactive,but when ingested by insects,they will produce toxin molecules through a series of biological reactions in insects.At this time,insecticidal proteins will play a lethal role in insects.Bt toxin in insects showed high specificity,and only had lethal effect on a small range of insects.The insecticidal proteins of Bacillus thuringiensis can be divided into Cry and Cyt,and the most important insecticidal protein is Cry crystal protein.Crystallin has three different domains.Under specific circumstances,the position of the crystal protein domain is exchanged in vitro to form a new fusion protein,which can change the binding characteristics of the toxin protein to the target insect specific receptor,enhance the toxicity of Bt protein,and produce resistance to a wider range of insects.In the early stage,our team combined the domain I and domain II of insect resistant gene Cry1 Ab and domain III of insect resistant gene Cry1 C to obtain a new fusion gene CryAAC.Then the CryAAC gene was combined with the expression vector and transformed into the genome of the recipient plants by Agrobacterium tumefaciens to obtain a new transgenic insect resistant material A6J7028.The target gene was detected in T1 generation of A6J7028.Based on the previous work of our research group,the target genes of T2,T3 and T4 generations of transgenic insect resistant material A6J7028 were detected to determine whether the target genes of the material were stably inherited in the progenies of transgenic plants.The experiment included PCR,Southern blot,ELISA,strip test and insect resistance identification.The results showed that nine groups of plants randomly selected from three different generations of transgenic materials were all positive by PCR detection;Southern hybridization map showed that the target gene CryAAC was transformed into the genome of recipient plants with 1 copy and could be stably inherited;ELISA results showed that the target protein existed in different tissue parts of three generations of plants;the expression of CryAAC was stable On the strip,there were two lines of quality control band and detection band in the plants randomly selected from three generations;the leaves of transgenic plants and untransformed recipient plants were inoculated in the laboratory respectively.After 5-7 days,it was observed that the damaged area of transgenic leaves was very small,and most larvae of Spodoptera litura died.However,there are few leaves left in the receptor material,and most of the pests survive and grow.These results indicate that CryAAC,the target gene of transgenic event A6J7028,can be stably inherited and expressed in the offspring of transgenic materials. |
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