Introgression of Bt Genes in Novel Germplasm and Contribution to Indian Cotton Economy

Emergence of transgenic Bt-cotton technology has opened up a new chapter in Indian cotton production in 21st century.The cry1Ac gene of Monsanto derived from American Upland Coker-312 background was not directly suitable for varied cotton growing situations in India.Delivery of

Breeding and Characterization of a New Rice Restorer Line Containing Bt Gene

Bt5198, a new rice restorer line containing Bt gene, was developed from the cross and backcross of the elite restorer line Chenghui 177 with Bt Minghui 63, a transgenic Bt restorer line. The inbred lines were evaluated using PCR amplification, test paper evaluation, insect resistance evaluation in both the laboratory and paddy fields, nursery evaluation of rice blast resistance and pedigree selection of agronomic traits. Larval mortalities on Bt5198 and Bt Minghui 63 were 100% when rice culms were inoculated with the eggs of the striped stem borer （SSB） in the laboratory. Bt5198 was highly resistant against SSB and the yellow stem borer （YSB） under field conditions. The F1 hybrids derived from Bt5198 and four cytoplasmic male sterile （CMS） lines were also highly resistant to SSB and YSB and had a significant heterosis. Two-year evaluation of rice blast resistance confirmed that the resistance levels of Bt5198 to leaf blast and neck blast were similar to those of Chenghui 177 and significantly better than those of Bt Minghui 63. Seed germination ability and pollen yield of Bt5198 were similar with Chenghui 177, suggesting that the introduction of the Bt gene into the new restorer line had no significant effects on seed vitality or the yield of seed production. To identify the presence of the Bt gene, it was effective to combine test paper examination with the evaluation of insect-resistance, both in the laboratory and under field conditions.

The Research of Bt and OC Gene Cotransformation in Tobacco Chloroplast

The Bt Cry IA (C) chloroplast expression cassette and OC chloroplast expression cassette were constructed. The Bt expression cassette contained the 3.5 kb wild type Bt Cry I4(C) gene under the control of the strong light-induced psbA promoter and terminator from rice (Oryza saliva . L) chloroplast, the gene: trnH-psbA-trnk from tobacco (Nicotiana tabacum. L) as the homologous fragment. The OC chloroplast expression cassette contained the OC gene under the control of 16S promoter and terminator from tobacco, the tobacco gene: psbA-ORF512 as homologous fragment. The two cassettes both had the aadA gene expression cassette as the selectable marker. Leaves of tobacco were cotransformed with the particle bombardment method. After selection by spectinomycin, the transformants were obtained. The integration of Bt and OC gene were confirmed by Southern-blotting analysis, and Western-blotting analysis. Proteinase inhibitor assays showed that the Bt and OC gene had expressed. Bioassays showed that the transgenic tobacco had a significant resistance to the larvae of cotton bollworm (helicoverpa zea).

Agrobacterium-meditated Genetic Transformation of an Upland Cotton(Gossypium hirsutum cv Coker 310) Using a Novel Bt Gene Cry2Ac

The development of transgenic cotton varieties resistant to bollworms has been a major success of applying plant genetic engineering technology to agriculture,evidenced by phenomenal increase in

Expression Characteristics and Borer Resistance of Bt Gene of Transgenic cry1C~* Super Japonica Rice

[Objective] The paper was to study the expression characteristics and borer resistance of Bt gene of Songjing 9 （1C^＊）. [Method] With super japonica rice Songjing 9 as the receptor, transgenic crylC^＊ super japonica rice Songjing 9 （1C^＊） regulated by ubi promoter was created by agrobacterium-mediated genetic transformation method. Ten strains of transgenic super japonica rice formed from different transformation events were planted in the field; the Tt-mRNA of leaf, stem-sheath and young spikelet at booting stage were detected by real-time fluorescent quantitative PCR; the Bt protein content of leaf, stem-sheath and young spikelet and harvested brown rice were detected by enzyme-linked immunosorbent assay （ELISA）; the white head rate damaged by Chilo suppressalis was manually investigated. [Result] The Bt-mRNA and Bt protein content of various organs and Bt protein content of mature brown rice at booting stage of Songjing 9 （1C^＊） significantly differed among strains; there was no correlation relationship in Bt-mRNA and Bt protein content between leaf and stem-sheath, between leaf and young spikelet, and between stem-sheath and young spikelet; there was no relation between Bt-mRNA or Bt protein content of leaf, stem-sheath and young spikelet and Bt protein content of brown rice; there was positive correlation between Bt-mRNA and Bt protein content in the same organ such as leaf, stem-sheath and young spikelet at booting stage; such strains as Songjing 9 （1C^＊）, whether the Bt gene expression was high or low, showed good resistance against C.suppressalis. This indicated that there were differences in Bt gene expression in different strains of transgenic cry1C^＊ super japonica rice or different organs of the same strain; there was no relation in Bt gene expression among different organs; the Bt-mRNA and protein content of the same organ usually had consistent expression; the Bt gene expression of various organs had nothing to do with the Bt protein content of brown rice. [Conclusion] The Bt gene and its expression cassette can meet the requirement of cultivating japonica rice varieties against stem borers.

Introduction of Bacillus thuringiensis(Bt)gene does not reduce potassium use efficiency of Bt transgenic cotton(Gossypium hirsutum L.)

Background:Potassium(K)deficiency has become a common field production problem following the widespread adoption of Bacillus thuringiensis(Bt)transgenic cotton(Gossypium hirsutum L.)worldwide.The purpose of this study was to clarify whether the introduction of Bt gene directly reduces the K-use efficiency of cotton to induce K deficiency.Results:The cotton variety,Jihe 321(wild type,WT)and its two Bt(Cry1Ac)-transgenic overexpression lines(OE-29317,OE-29312)were studied in field with low soil-test K+(47.8 mg·kg^(−1)).In the field with low soil-test K+,only OE-29317 had less biomass and K+accumulation than the WT at some growth stages.Both Bt lines produced similar or even greater seed cotton yield than WT in the field.When the Bt gene(~70%)in OE-29317 and OE-29312 plants was silenced by virus-induced gene silencing(VIGS),the VIGS-Bt plants did not produce more biomass than VIGSgreen fluorescent protein(control)plants.Conclusions:The introduction of Bt gene did not necessarily hinder the K use efficiency of the cotton lines under this study.

Development of lepidopteran pest-resistant transgenic japonica rice harboring a synthetic cry2A* gene

A synthetic cry2A^＊ gene enco ding Bacillus thuringiensis（Bt） δ-endotoxi n that resi st ance to lepidopteran pest was transformed into japonica rice variety Jijing 88, which is the most widely cultivated variety in Jilin Province, Northeast China, by Agrobacterium-mediated transformation. A total of 106 independent transformants overexpressing cry2A^＊ gene driven by ubiquitin（Ubi） promoter was produced. Three single-copy homozygous transgenic lines were finally selected based on the results of PCR analysis, se gregation ratio of Bast a resistance, and Southern hybridiza tion analyse s. RT-PCR and enzyme linke dimmune sorbent assay（ELISA） revealed that cry2A^＊ transcripts and protein were highly expressed in these lines. The high level of Cry2A^＊ protein expression resulted in high resistance to rice striped stem borer as evidence d by insect feeding bioassays. Our results demonst rate that cry2A^＊ transgenic japonica rice confers resistance to the rice striped stem borer in the laboratory conditions.

Advances in the Identification of Genetically Modified Rice with Real-time PCR and Multiplex PCR

In recent years, food security and safety have attracted increasing attention due to the worldwide research and development of genetically modified （GM） rice, and the controversy over the commercialization of GM rice. And the identification of GM rice is of great significance. Therefore, in the present study, the po- tential problems in the identification of GM rice with PCR were analyzed both at a technical level and from a theoretical perspective. In addition, PCR detection on the transgenic elements： promoter, terminator, internal reference gene and target gene was discussed, respectively. The possible solutions were proposed based on the principles of plant virology and genetic engineering.