Transgenic Bt Rice Research Articles

The effects of triazophos applied to transgenic Bt rice on the nutritional indexes, Nlvg expression, and population growth of Nilaparvata lugens Stål under elevated CO2

The brown planthopper, Nilaparvata lugens (Stål) (Hemiptera: Delphacidae), is a typical pest in which population resurgence can be induced by insecticides. Warmer global temperatures, associated with anthropogenic climate change, are likely to have marked ecological effects on terrestrial ecosystems. However, the effects of elevated CO2 (eCO2) concentrations on the resurgence of N. lugens that have been treated with pesticides used for transgenic Bt rice cultivation are not fully understood. The present study investigated changes in the protein content, soluble sugar content, free amino acid level, vitellogenin (Nlvg) mRNA expression, and the population growth of N. lugens on transgenic Bt rice (TT51) following triazaophos foliar spray under conditions of eCO2. The results showed that the protein content in the fat bodies and ovaries of N. lugens adult females in TT51 treated with 40 ppm triazophos under eCO2 was significantly higher than under ambient CO2 (aCO2) and was also higher than that in females feeding on the non-transgenic parent (MH63) under aCO2 at different days after emergence (DAEs). The soluble sugar content and free amino level of adult females in TT51 treated with 40 ppm triazophos under eCO2 was significantly higher than under aCO2 and was also higher than in MH63 under aCO2 at 1 and 3 DAE. The Nlvg mRNA expression level of N. lugens adult females in TT51 treated with 40 ppm triazophos under eCO2 was significantly higher than under aCO2 and was also higher than in MH63 under aCO2 at 1 and 3 DAE. The population number of N. lugens in TT51 treated with 40 ppm triazophos under eCO2 was significantly higher than under aCO2 and was also higher than in MH63 under aCO2. The present findings provide important information for integrated pest management with transgenic varieties and a better understanding of the resurgence mechanism of N. lugens under eCO2.

A 90-day subchronic feeding study of genetically modified rice expressing Cry1Ab protein in Sprague-Dawley rats.

Bacillus thuringiensis (Bt) transgenic rice line (mfb-MH86) expressing a synthetic cry1Ab gene can be protected against feeding damage from Lepidopteran insects, including Sesamia inferens, Chilo suppressalis, Tryporyza incertulas and Cnaphalocrocis medinalis. Rice flour from mfb-MH86 and its near-isogenic control MH86 was separately formulated into rodent diets at concentrations of 17.5, 35 and 70 % (w/w) for a 90-day feeding test with rats, and all of the diets were nutritionally balanced. In this study, the responses of rats fed diets containing mfb-MH86 were compared to those of rats fed flour from MH86. Overall health, body weight and food consumption were comparable between groups fed diets containing mfb-MH86 and MH86. Blood samples were collected prior to sacrifice and a few significant differences (p < 0.05) were observed in haematological and biochemical parameters between rats fed genetically modified (GM) and non-GM diets. However, the values of these parameters were within the normal ranges of values for rats of this age and sex, thus not considered treatment related. In addition, upon sacrifice a large number of organs were weighed, macroscopic and histopathological examinations were performed with only minor changes to report. In conclusion, these results demonstrated that no toxic effect was observed in the conditions of the experiment, based on the different parameters assessed. GM rice mfb-MH86 is as safe and nutritious as non-GM rice.

Prey-mediated effects of transgenic cry2Aa rice on the spider Hylyphantes graminicola, a generalist predator of Nilapavarta lugens

Concerns have been raised that transgenic Bt rice may have adverse effects on non-target natural enemies. The spider Hylyphantes graminicola is a generalist predator, and may be exposed to the insecticidal proteins expressed in Bt rice through ingestion of rice pests. Survival, developmental time, body weight and fecundity of the spider did not differ when fed on Nilapavarta lugens reared either on transgenic cry2Aa or nontransgenic rice based on a tritrophic bioassay. Similarly, the functional response of H. graminicola did not differ between Bt or non-Bt rice. Cry2Aa protein did not accumulate in this spider when the prey N. lugens fed on transgenic cry2Aa rice. No significant differences in population density and population dynamics were observed between H. graminicola in transgenic cry2Aa and nontransgenic rice fields during a three-year field investigation. The results indicates that the life-table parameters tested in the present study, population dynamics and density of H. graminicola were not affected by transgenic cry2Aa rice.

No direct effects of two transgenic Bt rice lines, T1C-19 and T2A-1, on the arthropod communities.

A 2-yr field trial was conducted to assess the impacts of two new transgenic Bt rice lines, T1C-19 expressing Cry1C protein and T2A-1 expressing Cry2A protein, on the arthropod community sampled via vacuum. All the arthropods were classified into five guilds, including herbivores, parasitoids, predators, detritivores, and others. The seasonal density and dominance distribution of each guild and community-level indices (species richness, Shannon-Wiener diversity index, Simpson diversity index, and evenness index) were compared among rice types. Principal response curves were used to investigate the differences of entire arthropod community of Bt rice plots relative to non-Bt rice plots. The results showed no significant difference was detected in the community-level indices and dominance distribution of guilds between Bt and non-Bt rice plots. The seasonal density of herbivores, detritivores, and others as well as density of the arthropod overall community were also not significantly affected by rice types in either year, although the density of predators and parasitoids in Bt rice plots was significantly lower than those in non-Bt rice plots. The lower abundances of Braconidae, Eulophidae, Cyrtorhinus lividipennis (Reuter) (Hemiptera: Miridae), and Theridiidae in Bt rice plots are likely attributed to the lower abundances of prey species or hosts. Principal response curves revealed that arthropod community in Bt was similar with that in non-Bt rice plots. In conclusion, our findings indicate that these two tested Bt rice lines had no marked negative effects on the arthropod community in the paddy fields.

Expression of Cry1Ab Protein in a Marker-Free Transgenic Bt Rice Line and Its Efficacy in Controlling a Target Pest,Chilo suppressalis(Lepidoptera: Crambidae)

A marker-free Bt transgenic rice line, mfb-MH86, was recently developed in China, which contains a cry1Ab gene driven by a ubiquitin promoter. This Bt gene confers resistance to a range of lepidopteran species, including the striped stem borer, Chilo suppressalis (Walker). The expression of Cry1Ab protein in mfb-MH86 leaves, stems and leaf sheaths (hereinafter referred to as stems), and roots was evaluated throughout the rice-growing season using an enzyme-linked immunosorbent assay. In addition, mfb-MH86 resistance to C. suppressalis, a major pest of rice, was evaluated in a laboratory bioassay with field-collected rice stems. Cry1Ab protein levels of mfb-MH86 were highest in leaves (9.71-34.09 μg/g dry weight [DW]), intermediate in stems (7.66-18.51 μg/g DW), and lowest in roots (1.95-13.40 μg/g DW). In all tissues, Cry1Ab levels in mfb-MH86 were higher in seedling and tillering stages than in subsequent growth stages. In the laboratory bioassay, mortality of C. suppressalis after 6 d of feeding on mfb-MH86 stems was 100% throughout the rice-growing season; mortality of C. suppressalis when feeding on stems of the nontransformed isoline, MH86, ranged from 15.0 to 38.3%. The results indicate that Cry1Ab protein levels in mfb-MH86 stems are sufficient to protect plants against C. suppressalis throughout the rice-growing season. Although our results are promising, further comprehensive evaluations of mfb-MH86, including field surveys, will be needed before commercial use.

温度和[CO2]升高下转Bt水稻种植对土壤活性碳氮和线虫群落的短期影响

Interactions of global change and transgenic Bt rice( Huahui-1,HH1) cropping on soil ecosystem remain largely unexplored. Here we conducted an OTC( Open Top Chamber) experiment to evaluate the effects of transgenic Bt rice cropping on soil labile organic carbon and nitrogen,and nematode communities under elevation of temperature and [CO2] with two rice varieties including non-Bt rice( MH63) and its transgenic Bt line( HH1). Results showed that( 1) Under the condition of elevated [CO2]and warming,transgenic Bt rice cropping significantly affected the content of soil dissolved organic carbon,dissolved organic nitrogen and NO-3-N. Significantly interactions of transgenic Bt rice,warming and elevated [CO2]were observed for the content of soil dissolved organic carbon and dissolved organic nitrogen. Further,the transgenic Bt rice reduced microbial biomass carbon and nitrogen significantly under ambient temperature and [CO2]; whereaswarming and [CO2]elevation reversed that trend.( 2) At ambient temperatures and[CO2],the total number of nematodes in soil grown with transgenic Bt rice cropping were significantly more than those in soil grown with the parental line. Herbivorous nematodes tended to increase under the condition of warming and elevated [CO2],though not reaching to a significant level. Transgenic Bt rice and warming significantly increased the Nematode Channel Ratio,demonstrating the shift from bacteria-dominated to fungi-dominated energy channel. But [CO2]elevation and transgenic Bt rice significantly increased the nematode Enrichment Index. In conclusion,climate change modified the responses of soil labile organic matter and nematode community to transgenic Bt rice cropping,though it does not lead to negative effects on soil based on the results of short-term experimental duration.

The construction of a fluorescent nano-probe and its application in detecting transgenic Bt rice TT51-1

A fluorescent nano-probe that simultaneously detects the rice endogenous housekeeping gene SPS and the exogenous Bt gene (Cry1Ab/Ac).

13C pulse-chase labeling comparative assessment of the active methanogenic archaeal community composition in the transgenic and nontransgenic parental rice rhizospheres

More and more investigations indicate that genetic modification has no significant or persistent effects on microbial community composition in the rice rhizosphere. Very few studies, however, have focused on its impact on functional microorganisms. This study completed a ¹³C-CO₂ pulse-chase labeling experiment comparing the potential effects of cry1Ab gene transformation on ¹³C tissue distribution and rhizosphere methanogenic archaeal community composition with its parental rice variety (Ck) and a distant parental rice variety (Dp). Results showed that ¹³C partitioning in aboveground biomass (mainly in stems) and roots of Dp was significantly lower than that of Ck. However, there were no significant differences in ¹³C partitioning between the Bt transgenic rice line (Bt) and Ck. RNA-stable isotope probing combined with clone library analyses inferred that the group Methanosaetaceae was the predominant methanogenic Archaea in all three rice rhizospheres. The active methanogenic archaeal community in the Bt rhizosphere was dominated by Methanosarcinaceae, Methanosaetaceae, and Methanomicrobiaceae, while there were only two main methanogenic clusters (Methanosaetaceae and Methanomicrobiaceae) in the Ck and Dp rhizospheres. These results indicate that the insertion of cry1Ab gene into the rice genome has the potential to result in the modification of methanogenic community composition in its rhizosphere.

Leaf Morphology and Ultrastructure Responses to Elevated O3 in Transgenic Bt (cry1Ab/cry1Ac) Rice and Conventional Rice under Fully Open-Air Field Conditions

BackgroundElevated tropospheric ozone severely affects not only yield but also the morphology, structure and physiological functions of plants. Because of concerns regarding the potential environmental risk of transgenic crops, it is important to monitor changes in transgenic insect-resistant rice under the projected high tropospheric ozone before its commercial release.Methodology/Principal FindingsUsing a free-air concentration enrichment (FACE) system, we investigated the changes in leaf morphology and leaf ultrastructure of two rice varieties grown in plastic pots, transgenic Bt Shanyou 63 (Bt-SY63, carrying a fusion gene of cry1Ab and cry1Ac) and its non-transgenic counterpart (SY63), in elevated O3 (E-O3) versus ambient O3 (A-O3) after 64-DAS (Days after seeding), 85-DAS and 102-DAS. Our results indicated that E-O3 had no significant effects on leaf length, leaf width, leaf area, stomatal length and stomatal density for both Bt-SY63 and SY63. E-O3 increased the leaf thickness of Bt-SY63, but decreased that of SY63. O3 stress caused early swelling of the thylakoids of chloroplasts, a significant increase in the proportion of total plastoglobule area in the entire cell area (PCAP) and a significant decrease in the proportion of total starch grain area in the entire cell area (SCAP), suggesting that E-O3 accelerated the leaf senescence of the two rice genotypes. Compared with SY63, E-O3 caused early swelling of the thylakoids of chloroplasts and more substantial breakdown of chloroplasts in Bt-SY63.Conclusions/SignificanceOur results suggest that the incorporation of cry1Ab/Ac into SY63 could induce unintentional changes in some parts of plant morphology and that O3 stress results in greater leaf damage to Bt-SY63 than to SY63, with the former coupled with higher O3 sensitivity in CCAP (the proportions of total chloroplast area in the entire cell area), PCAP and SCAP. This study provides valuable baseline information for the prospective commercial release of transgenic crops under the projected future climate.

A two-generation reproduction study with transgenic Bt rice TT51 in Wistar rats

TT51 is a transgenic Bt rice created by fusion a synthetic CryAb/CryAc gene into rice MingHui63. A significant number of animal feeding studies with transgenic crops have been carried out with the rapid development of transgenic crops. However, the evidence is far from identifying whether certain novel transgenic crops possess potential danger for human or animal health after long-term consumption. Rice-based diets, containing 60% ordinary grocery rice, MingHui63 rice or TT51 rice by weight, were fed to two generations of male and female rats in order to determine the potential reproductive effects of TT51. In this study, both clinical performance variables and histopathological responses were examined and compared between groups. There were no significant differences between groups on body weights, food consumption, reproductive data and relative organ/body weights. There were some statistically significant differences in hematology and serum chemistry parameters, but no histological abnormalities were seen in the brain, heart, liver, spleen, kidneys, stomach, small intestine, thymus, ovaries, uterus, testes and epididymides. Based on the results, under the circumstance of this study TT51 show no significant differences on reproduction performance of rats compared with MingHui63 and the control.

Single and fused transgenic Bacillus thuringiensis rice alter the species‐specific responses of non‐target planthoppers to elevated carbon dioxide and temperature

The approval of transgenic Bacillus thuringiensis (Bt) rice by China was momentous for biotech crops, although it has yet to be approved for commercial production. Non-target pest problems in rice paddies, such as the three ecologically similar species of planthoppers Nilaparvata lugens, Laodelphax striatellus and Sogatella furcifera, could become increasingly serious under global climate change. Fused (Cry1Ab/Cry1Ac) and single (Cry1Ab) transgenic Bt rice were evaluated for effects on species-specific responses of planthoppers to elevated carbon dioxide (CO2) and temperature. Transgenic Bt rice lines significantly modified species-specific responses of the planthoppers to elevated CO2 and temperature. High temperature appears to favour outbreaks of S. furcifera relative to N. lugens and L. striatellus when feeding upon fused transgenic Bt rice, especially at elevated CO2 . Elevated CO2 at high temperature appears to be a factor reducing S. furcifera occurrence when feeding upon single transgenic Bt rice. Different types of transgenic Bt rice alter the species-specific responses of non-target planthoppers to elevated CO2 and temperature. Compared with their non-transgenic parental lines, the single transgenic Bt rice shows better performance in controlling the non-target planthopper S. furcifera by comparison with the fused transgenic Bt rice under elevated CO2 and temperature. It is suggested that multitypes of transgenic Bt rice be used in the field simultaneously in order to take advantage of high transgenic diversity for optimal performance against all pests in paddy fields.

Transgenic Bt Rice Does Not Challenge Host Preference of the Target Pest of Rice Leaffolder, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae)

BackgroundTransgenic Bt rice line T2A-1 expresses a synthesized cry2A gene that shows high resistance to Lepidoptera pests, including Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae). Plant volatile orientation cues and the physical characteristics of the leaf surface play key roles in host location or host-plant acceptance of phytophagous insects. These volatile compounds and physical traits may become altered in Bt rice and it is not known whether this influences the behavior of C. medinalis when searching for oviposition sites.ResultsThe results of electronic nose analysis showed that the Radar map of Bt rice cultivars was analogous to the non- Bt rice cultivars at each growing stage. PCA analysis was able to partly discriminate between some of the Bt vs. non-Bt rice sensors, but could not to separate Bt cultivars from non-Bt cultivars. The total ion chromatogram between Bt and non-Bt rice cultivars at the seedling, booting and tillering stages were similar and 25 main compounds were identified by GC-MS. For most compounds, there was no significant difference in compound quantities between Bt and non-Bt rice cultivars at equivalent growth stages. The densities of the tubercle papicles and the trichomes on the upper and lower surfaces were statistically equal in Bt and non-Bt rice. The target pest, C. medinalis, was attracted to host rice plants, but it could not distinguish between the transgenic and the isogenic rice lines.ConclusionsThere were no significant differences between the Bt rice line, T2A-1 and the non-Bt rice for volatiles produced or in its physical characteristics and there were no negative impacts on C. medinalis oviposition behavior. These results add to the mounting evidence that Bt rice has no negative impact on the target insect oviposition behavior.

Assessment of yield advantages of Bt-MH63 with cry1C* or cry2A* genes over MH63 (Oryza sativa L.) under different pest control modes

Transgenic Bacillus thuringiensis (Bt) rice had been successfully cultivated to maintain yield potential of rice under pest invasion. Yield and resistance performance of the transgenic Bt rice are important to be meticulously evaluated under different pest pressures. Field experiments were conducted to investigate field performances of Bt-MH63 with cry1C* or cry2A* genes under four pest control modes: chemical control for all the pests (MPC), no chemical control for the target pests (MNTP), chemical control for the target pests (MTP) and no chemical control for all the pests (MNPC). The results showed that the maximum yield advantages of MH63 (cry1C*) and MH63 (cry2A*) over MH63 were 8.4 and 25.4% (P<0.05) under MNTP, respectively. The grain yield of MH63 (cry1C*) was lower than that of MH63 under MPC and MTP. Moreover, the grain yield of MH63 (cry2A*) was lower than that of MH63 under MTP only. The correlation analysis revealed that the yield advantages of Bt-MH63 over MH63 were positively correlated with the damage to MH63 (expressed as percentage of white leaves) caused by leaffolders (Cnaphalocrocis medinalis Guenee). Although MH63 (cry1C*) and MH63 (cry2A*) showed great differences in Bt protein contents in their leaves, they had high effective resistances to leaffolders. It can be concluded that Bt-MH63 had obvious yield advantages over MH63 when no pesticides were applied against the target pests. However, yield reductions in Bt-MH63 were existed when pesticides were applied against the target pests.

Grain yield and nitrogen use efficiency responses to N application in Bt (Cry1Ab/Ac) transgenic two-line hybrid rice

Transgenic crops with Bacillus thuringiensis (Bt) have been reported to be effective in controlling pests, and some Bt transgenic lines have been used to develop hybrid crop varieties including three-line and two-line hybrid rice (THR). However, it is unclear whether the insertion of an external Bt gene affects nitrogen uptake and N use efficiency (NUE) along with the grain yield of Bt-THR. Thus, field experiments were conducted in two adjacent fields located at Zhangbang village, Hubei province, China from May to October in 2011 and 2012. Treatments were arranged using a split-plot design with four replications. The main plots were N treatments with three rates (90, 135, 180kgha−1) in 2011 and four rates (0, 90, 135, 180kgha−1) in 2012. Four different tested varieties were grown in the subplots. The three Bt-THR examined were Guangliangyou-19 (GLY-19), Chuanyou-4198 (CY-4198), and Zheyou-3 (ZY-3), and the non-Bt control was Yangliangyou-6 (YLY-6) which was used as the check for the national variety traits in China at present. Pests (including Bt target pests, diseases and weeds) were strictly controlled to avoid yield loss. No significant differences were observed in the grain yield between GLY-19, ZY-3 and YLY-6 at each N application for both years. However, the grain yield in response to different N rates varied among different Bt-THR varieties and the control. CY-4198 showed a sensitive N response trait, which produced a maximum grain yield at 90kgNha−1, and further increases in N rates caused a yield decline. The other Bt-THR varieties demonstrated insensitive N responses similar to the control, where the maximum grain yield was at 135kgNha−1 and showed no significant yield decline when applied at 180kgNha−1 in both years. Among the three Bt-THR varieties, GYL-19 and ZY-3 demonstrated a similar N uptake ability, agronomic nitrogen use efficiency, N harvest index, N translocation efficiency, and recovery efficiency compared to the control, whereas those for CY-4198 was lower when the N application exceeded 90kgNha−1. In conclusion, some Bt-THR varieties (GLY-19 and ZY-3) demonstrated a comparable yield potential to the super hybrid control (YLY-6). Moreover, there was no evidence that insertion of the Bt gene changed N uptake and NUE-related traits, which indicated that the optimal N managements adapted by the THR varieties could also be introduced to Bt-THR. Thus, screening Bt-THR varieties might represent a feasible approach to synergistically improve grain yield and pest resistance without disrupting N nutrition.

무선발 형질전환 Bt벼의 도입유전자 구조 분석

Abstract A less simple approach developed for generation of marker-free transgenic plants is to select transformants without the use of selective marker genes. Some results about development of marker-free transgenic plants were obtained using a non-selective approach in several crops such as rice, potato and tobacco. However, the study did not provide evidence on detailed characterization of introduced gene on genome, a critical step for confirming the stable integration and transmission of a foreign gene. In this study, we evaluated structure and integration sites of transgene (m Cry1Ac ) in the transgenic Bt rice plants which were made via conventional Agrobacterium -mediated transformation by non-selective method. Structure and integration sites of transgene in these transgenic plants had similar fashion as those recovered under selection. Keywords Non-selective, Marker-free transgenic rice, Agrobacterium -mediated transformation, Transgene, integration site 서 론 선발마커유전자(Selective marker gene)는 목표유전자와 연결하여, 도입유전자가 형질전환 된 식물체를 선택적으로 선발하는데 사용된다. 통상적으로

Effects of 90-day feeding of transgenic Bt rice TT51 on the reproductive system in male rats

Rice is a staple food crop; however, the threat of pests leads to a serious decline in its output and quality. The CryAb/CryAc gene, encodes a synthetic fusion Bacillus thuringiensis (Bt) crystal protein, was introduced into rice MingHui63 to produce insect-resistant rice TT51. This study was undertaken to investigate potential unintended effects of TT51 on the reproductive system in male rats. Male rats were treated with diets containing 60% of either TT51 or MingHui63 by weight, nutritionally balanced to an AIN93G diet, for 90days. An additional negative control group of rats were fed with a rice-based AIN93G diet. Body weights, food intake, hematology, serum chemistry, serum hormone levels, sperm parameters and relative organ/body weights were measured, and gross as well as microscopic pathology were examined. No diet-related significant differences in the values of response variables were observed between rats that were fed with diet containing transgenic TT51, MingHui63 and the control in this 90-day feeding study. In addition, necropsy and histopathology examination indicated no treatment-related changes. The results from the present study indicated that TT51 does not appear to exert any effect on the reproductive system in male rats compared with MingHui63 or the control.

Effects of Pesticide Applications on the Biochemical Properties of Transgenic cry 2A Rice and the Life History Parameters of Nilaparvata lugens Stål (Homptera: Delphacidae)

Effects of transgenic Bt rice on non-target pests following pesticide applications plays an important role in evaluating the ecological safety of transgenic rice. Changes of the life history parameters of laboratory population of Nilaparvata lugens feeding on transgenic Bt rice T2A-1 and its parental line cv. MH63 as the control, and the contents of oxalic acid and soluble sugar following three pesticides (triazophos, jinggangmycin and chlorantraniliprole) treatments were investigated in this paper. Results showed that the population parameters of N. lugens and the physiological and biochemical parameters of rice did not differ significantly between T2A-1 and MH63 without pesticide application. But, the emergence rate (ER), the nymphal number of next generation (NN), and the index of population trend (IP) on T2A-1 treated with 10 mg L−1 of triazophos were significantly higher than those on MH63, respectively, while the hatchability (HB) on T2A-1 treated with the three pesticides were obviously lower than those on MH 63. Furthermore, the content of oxalic acid in MH63 treated with 20 mg L−1 triazophos and, 40 and 80 mg L−1 chlorantraniliprole was significantly higher than that in T2A-1, while the content of soluble sugar in T2A-1 treated with 400 mg L−1 jinggangmycin was significantly higher than that in MH63. The results above indicated that triazophos in a low dose could cause a more favor of T2A-1 to population growth of N. lugens compared with MH 63.

Development of elite rice restorer lines in the genetic background of R022 possessing tolerance to brown planthopper, stem borer, leaf folder and herbicide through marker-assisted breeding

Rice leaf folder, stem borer and brown planthopper (BPH) are the most devastating rice insect pests. Developing and planting insect-resistant rice varieties is the most economical and effective measure for controlling these pests. BPH can be controlled with native BPH-resistance genes in rice, while at present rice leaf folder and stem borer can only be controlled through planting transgenic Bt rice. In this study, the breeding of a new restorer line KR022 possessing stacked BPH-resistance genes Bph14 and Bph15, Bt gene cry1C and glufosinate-resistance gene bar, is reported for the first time. A rice restorer line R022 with BPH-resistance genes Bph14 and Bph15 was used as a recurrent parent to cross with the transgenic rice T1C-19 of cry1C and bar genes during the breeding process. The restorer line KR022 was developed from the backcross populations of R022 and T1C-19 through molecular marker-assisted selection and glufosinate-resistance selection. The cry1C and bar genes were found to integrate on chromosome 11 of KR022, and the genome recovery of KR022 was up to 95.8 % of the R022 genome. The quantification of Cry1C protein expression showed that it was expressed at different levels in the leaf, stem, panicle, endosperm, and root of KR022 and its hybrid rice. The insect-resistance evaluation indicated that KR022 and its hybrid rice had good resistance to rice leaf folder and stem borer, both in laboratory settings and in the field. Furthermore, they exhibited increased resistance to BPH at both the seedling and mature stage. The field trial showed there was no significant difference in key agronomic traits between KR022 and its recurrent parent R022, and four hybrids from KR022 yield much higher than the control II-You 838. Moreover, KR022 and its hybrid rice were found to have resistance to the herbicide glufosinate. These results demonstrate that KR022 is effective as a rice restorer line for the breeding of “green super rice”, possessing multiple tolerances to rice BPH, stem borer, leaf folder and glufosinate.

Zero effect of Bt rice on expression of genes coding for digestion, detoxification and immune responses and developmental performances of Brown Planthopper Nilaparvata lugens (Stål)

Transgenic Cry1Ac, Cry2Aa and Cry1Ca (Bt toxins) rice lines are well developed to manage lepidopteron pests in China. The impact of transgenic Bt rice on the non-target Brown Planthopper (BPH) has become an essential part of environmental risk assessment, however, scanty evidence is found addressing on developmental and molecular responses of BPH to the ingestion of Bt protein from transgenic rice. The focus of the current study is to examine the developmental characteristics and the expression profiles of gene in relation to digestion, detoxification and immune responses were examined. Our study strongly revealed that the tested Bt rice strains have no unfavorable effect on fecundity, survival and growth of BPH. Furthermore, each of the tested genes did not exhibit distinct expression pattern responding to non Bt parental cultivar, thus, it could be concluded that Bt rice have no detrimental effects on the physiological processes of digestion, detoxification and immune responses of BPH.

Effects of triazophos on biochemical substances of transgenic Bt rice and its nontarget pest Nilaparvata lugens Stål under elevated CO2

The brown planthopper (BPH), Nilaparvata lugens Stål, is a serious rice pest throughout Asia. Recent outbreaks of N. lugens populations were mainly associated with the overuse of pesticides and resistance to insecticides. Warmer global temperatures that are associated with anthropogenic climate change are likely to have marked ecological effects on terrestrial ecosystems. However, the effects of elevated CO2 concentrations on the biochemical, physiological and nutrient quality of transgenic Bt rice that has been treated with pesticides and on the control efficacy of the pesticides are not understood. The present study investigated changes in soluble sugar content, free amino acid levels, oxalic acid levels, flavonoids levels, and triazophos residues in transgenic Bt rice (TT51) and the control efficacy of triazophos for N. lugens following triazophos foliar spray under conditions of elevated CO2 (eCO2). Our findings showed that the soluble sugar content of TT51 treated with triazophos under eCO2 was significantly higher than that under ambient CO2 (aCO2) and also higher than that of the non-transgenic parent (MH63) under aCO2. However, the results for free amino acid levels were the opposite of those for soluble sugar levels. The oxalic acid and flavonoid contents of rice plants significantly decreased with increases in triazophos concentration, CO2 concentration, and days after treatment (DAT). The oxalic acid and flavonoid contents of TT51 treated with triazophos under eCO2 were significantly lower than those under aCO2 and also lower than those of MH63 under aCO2. The residue concentration of triazophos varied with CO2 concentration, rice variety, and DAT. The residues in TT51 treated with 80ppm of trizaopos under eCO2 were significantly lower than those under aCO2 and those in MH63 under aCO2. The survival rate of nymphs N. lugens in TT51 under eCO2 was significantly higher than that under aCO2 and that in MH63 under aCO2 at 1 DAT or 15 DAT after the release of 2nd instars nymphs. These findings indicated that (1) for TT51, triazophos reduced the resistance of rice plants to N. lugens with an elevated CO2 concentration, as N. lugens consumed more phloem sap on TT51 plants; (2) triazophos dissipation in TT51 under eCO2 was significantly faster than that under aCO2 and that in MH63 under aCO2; (3) the control efficacy of triazophos for N. lugens significantly decreased under eCO2. The present findings provide important information for integrated pest management among transgenic varieties.