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棉花抗虫工程菌是通过综合质粒载体，将 Ｂａｃｉｌｌｕｓ ｔｈｕｒｉｎｇｉｅｎｓｉｓ（Ｂｔ） 杀虫晶体蛋白基因 ｃｒｙＩＡ（ｃ）整合到棉花优势内生细菌 Ｂａｃｉｌｌｕｓ ｃｅｒｅｕｓ Ｂｃ９００２的染色体上构建的重组工程菌。对该工程菌的染色体酶切分析、ＰＣＲ扩增、ＳＤＳ－ＰＡＧＥ、ＥＬＩＳＡ检测、晶体毒蛋白的电镜观察和毒力测定等检测后，将其分别以３种方式（注射、喷雾、浸种）接种棉花。该工程菌在棉株内的种群数量呈现动态变化：接种２周后，菌量开始猛增，４－６周时达到最高峰约为８．８×１０８ＣＦＵ／ｇ植物组织，然后开始回落，１０周时达到接种时的菌量水平（１０３～１０4ＣＦＵ／ｇ植物组织）。工程菌在数量消长的同时，抗虫基因ｃｒｙＩＡ（ｃ）也逐步发生丢失，出现分化，其分化率（即ｃｒｙＩＡ（ｃ） 基因丢失率）为：接种２周后约为３０％，４周时约为５０％。而接种方式对工程菌的分化率影响不大，但不同接种方式和接种菌量会对工程菌株在棉株内的消长变化产生一定的影响。
Cotton insect-resistant engineering bacterium is a recombinant engineering bacterium constructed by integrating the cryIA (c) gene of the Bacillus thuringiensis (Bt) insecticidal crystal protein gene into the chromosome of Bacillus cereus Bc9002, a cotton endophytic bacterium through a synthetic plasmid vector. Chromosome analysis of the engineered bacteria, PCR amplification, SDS-PAGE, ELISA test, electron microscopic observation of crystal toxic protein and virulence determination test, respectively, were in three ways (injection, spray, soaking) cotton. The quantity of the engineered bacteria in cotton plants showed a dynamic change. After 2 weeks of inoculation, the bacterial counts began to increase sharply, reached the peak of 8.8 × 108CFU / g at 4-6 weeks, and then began to decline. 10 Week when the amount of bacteria reached the level of vaccination (103 ~ 104CFU / g plant tissue). Meanwhile, cryIC (c) also gradually lost and differentiated. The rate of differentiation (ie, cryIA (c) gene loss rate) was about 30% after 2 weeks of inoculation, and at 4 weeks About 50%. However, the inoculation method had little effect on the rate of differentiation of engineering bacteria, but the different inoculation methods and inoculation amount of bacteria would affect the growth and decline of engineering strains in cotton plants to a certain extent.