A dual-RPA based lateral flow strip for sensitive,on-site detection of CP4-EPSPS and Cry1Ab/Ac genes in genetically modified crops

Traditional transgenic detection methods require high test conditions and struggle to be both sensitive and efficient.In this study,a one-tube dual recombinase polymerase amplification(RPA)reaction system for CP4-EPSPS and Cry1Ab/Ac was proposed and combined with a lateral flow immunochromatographic assay,named“Dual-RPA-LFD”,to visualize the dual detection of genetically modified(GM)crops.In which,the herbicide tolerance gene CP4-EPSPS and the insect resistance gene Cry1Ab/Ac were selected as targets taking into account the current status of the most widespread application of insect resistance and herbicide tolerance traits and their stacked traits.Gradient diluted plasmids,transgenic standards,and actual samples were used as templates to conduct sensitivity,specificity,and practicality assays,respectively.The constructed method achieved the visual detection of plasmid at levels as low as 100 copies,demonstrating its high sensitivity.In addition,good applicability to transgenic samples was observed,with no cross-interference between two test lines and no influence from other genes.In conclusion,this strategy achieved the expected purpose of simultaneous detection of the two popular targets in GM crops within 20 min at 37°C in a rapid,equipmentfree field manner,providing a new alternative for rapid screening for transgenic assays in the field.

Research Progress of Agricultural Genetically Modified Crop Safety Evaluation

The commercial cultivation of genetically modified(GM)crops has eased the global food crisis and brought considerable economic and social benefits to countries.Because of the potential safety problems,it is necessary to make clear the molecular genetic characteristics,edible safety,planting,processing,and other aspects of the safety evaluation of GM crops.The safety problems existing in the cultivation of GM crops,safety evaluation and detection of GM crops were introduced in this paper,which provided the basis for safety evaluation and effective supervision of GM crops and their products.Commercial cultivation and reasonable supervision based on safety evaluation have far-reaching significance for ensuring consumer safety,enhancing the credibility of the national political system and enhancing citizens'confidence in the safety of GM crop products for consumption.

Georgian Farmers＇ Attitudes Towards Genetically Modified Crops

Although, genetically engineered products （GM） have to be a broadly debated topic in different countries, there has been much less attention devoted to farmers＇ attitudes towards GM crops. This paper attempts to research farmers＇ insights on GM crops in Georgia through February-March 2014. An in-depth survey of 611 farmers revealed that respondents lack sufficient knowledge about genetic engineering. They tend to have a negative attitude towards GM crops and are strongly against of import and adoption of GM seeds. An empirical examination based on analysis of variance and Pearson＇s correlation coefficient verified that both education and age were significant determinants of awareness of farmers about genetically engineered crops, while income used to have no significant influence on the farmers＇ decision to adopt GM crops. In addition, relationship between awareness about genetic engineering and farmers＇ decision to adopt GM crops has to be insignificant, as well.

Impact of Crop Rotation on Pathotype and Genetic Structure of Phythophthora sojae in Fields

To estimate the impact of crop rotation on the pathotype and genetic structure of Phythophthora sojae in fields, 372 isolates of P. sojae were obtained from long-term localisation experimental fields in Heilongjiang Province of China. The hypocotyl inoculation method was used to characterize the virulence of P. sojae on 13 differential cultivars, and the amplified fragment length polymorphism（AFLP） technique was used to analyze difference in the genetic structure of P. sojae. The results indicated that an abundant diversity of genetic structures and pathotypes of P. sojae, a more uniform distribution of pathotypes and less dominance of pathotypes occurred in corn-soybean and wheat-soybean rotation fields than in a continuous soybean mono-cropping field. These findings suggested that P. sojae did not easily become the dominant race in rotation fields, which maintain disease resistance in soybean varieties. Therefore, the results of this study suggested that Phytophthora stem and root rot of soybeans could be effectively controlled by rotating soybeans with non-host crops of corn and wheat.

A Preliminary Study on Systems Engineering-Based Method for the Evaluation of Allelopathic Potential in Crops and Its Application

The objective of this study was to develop a method to assess and analyze the total allelopathic potential of crop germplasm and to test this method on four winter wheat accessions commonly planted in the Loess Plateau. A systems engineering model was developed and used to evaluate the total allelopathic potential of crop cultivars. In addition, a method for quantifying the total allelopathic potential in crop accessions was presented. Total allelopathic potential of four winter wheat accessions from the Loess Plateau was estimated and compared using a systems theory approach. The model assessed allelopathic potential in different parts of the plants from the time wheat turned green in spring until maturity. Results from these models indicated that the four wheat accessions had very weak allelopathic potential. Allelopathic potential declined in the order Xiaoyan 22 〉 Ningdong 1 〉 Fengchan 3 〉 Bima 1. This system engineering evaluation method allows for the assessment of allelopathic potential among crop varieties. It will help plant breeders to select and develop allelopathic crop accessions that combine weed suppression properties with agronomic traits related to yield and quality.

Effect of Bt traits on transgenic rice's growth and weed competitiveness

Transgene escape could lead to genetically modified rice establishing wild populations in the natural environment and competing for survival space with weeds.However,whether the expression of the Bacillus thuringiensis(Bt)gene in rice will alter the relationship between transgene plants and weeds and induce undesirable environmental consequences are poorly understood.Thus,field experiments were conducted to investigate the weed competitiveness and assess the ecological risk of transgenic Bt rice under herbicide-free and lepidopterous pest-controlled environments.Results showed that weed–rice competition in the direct-sowing(DS)field was earlier and more severe than that in the transplanting(TP)field,which resulted in a significant decrease in biomass and yield in DS.However,conventional Bt and non-Bt rice yield was not significantly different.The weed number,weed coverage ratio,and weed diversity of conventional Bt rice were significantly higher than those of non-Bt rice at the early growth and mature stages,especially in DS plots,suggesting that Bt traits did not increase the weed competitiveness of transgenic rice and had no negative effect on weed diversity.Grain yield and weed number varied between different hybrid rice lines,but those differences were insignificant between Bt and non-Bt rice.The number of insects increased with the increase of weeds in hybrid rice plots,whereas the insect number and diversity did not display a significant difference between Bt and non-Bt rice.Therefore,the ecological risk of transgenic Bt rice is comparable to non-Bt rice.

Trends in the global commercialization of genetically modified crops in 2023

The commercialization of genetically modified(GM)crops has increased food production,improved crop quality,reduced pesticide use,promoted changes in agricultural production methods,and become an important new production strategy for dealing with insect pests and weeds while reducing the cultivated land area.This article provides a comprehensive examination of the global distribution of GM crops in 2023.It discusses the internal factors that are driving their adoption,such as the increasing number of GM crops and the growing variety of commodities.This article also provides information support and application guidance for the new developments in global agricultural science and technology.

Genetic Variability of Pumpkin Landraces in Brazilian Amazon

The family farm of the Upper Solim?es region has maintained the great genetic variability of the pumpkin (Cucurbita maxima Duchesne) by the in situ conservation of the landraces which are widely used as human food. The aim of this study was to estimate the current level of genetic variability of pumpkin landraces by means of estimation techniques of genetic parameters. Landraces areas samples were the family farming production units located in floodplains ecosystems of Benjamin Constant (Upper Solim?es River) and Iranduba (Lower Solim?es River), Amazonas. The split-plot designs were adopted at the treatments where the main plots were the five pumpkin landraces and one commercial cultivar. Each landrace was obtained six half sib families distributed in the sub-plots. Among the results of this study, it can be concluded that the genetic variation within the each landrace is greater than the genetic variation among the landraces. The qualitative morphological characteristics bring together half-sib families collected in geographically distant locations. It can be concluded that, through the estimation of genetic parameters, there is genetic variability among local cultivars collected in family farming of Benjamin Constant and Iranduba, Amazonas.

Molecular Study of the Genetic Variability of Pumpkins Landraces from Brazilian Amazon

The Cucurbita maxima Duchesne is a vegetable crop plant cultivated and maintained by traditional Amazon communities, Brazil. The situation is worsened by the possibility of disappearance of local populations and genetic variability of this specie, taking into account the today changes promoted in family farming. The aim of this study was to estimate the current levels of genetic variability of local cultivars through the use of molecular markers (Amplified Fragment Length Polymorphism—AFLP). We chose to collect in two distinct micro regions in order to identify possible influences of geographic isolation and different levels of market requirements in the conservation of the genetic variability of the C. maxima. For the molecular analysis, bulk samples of fresh leaves of 15 plants/half-sibling family were collected in paper bags. There were 34 samples from the half-sib families. The analysis of the results half-sib obtained by methods of estimation of genetic variation by molecular markers shows that the forms of cultivation and management adopted by family farmers maintain the identities of the local/landraces (native cultivars) and, at the same time, the levels of diversity for the assurance of adaptability macro-environmental.

Risk Assessment and Biosafety Studies of Transgenic Bt Rice （Oryza sativa L.）

Transgenic crops having alien genes from different sources are getting popularity. A Rice （Oryza sativa L.） containing gene from Bacillus thuringiensis, a soil bacterium, was assessed to study the potential risks of transgenic plants on environment. The crop was found resistant to target insect pests. Rice variety Basmati-370 transformed with two insecticidal genes, crylAc and cry2A, was grown under field conditions for several years. Data were collected at different stages of the plant growth. Fate of Cry protein in soil, effect of Bt protein on non-target insects, risks of vertical and horizontal gene flow were evaluated. No potential hazard was found at all levels. Bt protein was unstable and degraded significantly in soil within 30 days after harvesting the crop. No harmful effects were found on non-target insects （insects other than order lepidoptera）. Maximum gene flow of 0.02% was observed at close spacing and no evidence of horizontal gene transfer to Rhizobium spp. was found. In conclusion, the transgenic rice plants transformed with Bt genes have no harmful effects on the environment.

The OsSRO1c-OsDREB2B complex undergoes protein phase transition to enhance cold tolerance in rice

Cold stress is one of the major abiotic stress factors affecting rice growth and development,leading to significant yield loss in the context of global climate change.Exploring natural variants that confer cold resistance and the underlying molecular mechanism responsible for this is the major strategy to breed cold-tolerant rice varieties.Here,we show that natural variations of a SIMILAR to RCD ONE(SRO)gene,OsSRO1c,confer cold tolerance in rice at both seedling and booting stages.Our in vivo and in vitro experiments demonstrated that OsSRO1c possesses intrinsic liquid–liquid phase-separation ability and recruits OsDREB2B,an AP2/ERF transcription factor that functions as a positive regulator of cold stress,into its biomolecular condensates in the nucleus,resulting in elevated transcriptional activity of OsDREB2B.We found that the OsSRO1c-OsDREB2B complex directly responds to low temperature through dynamic phase transitions and regulates key cold-response genes,including COLD1.Furthermore,we showed that introgression of an elite haplotype of OsSRO1c into a cold-susceptible indica rice could significantly increase its cold resistance.Collectively,our work reveals a novel cold-tolerance regulatory module in rice and provides promising genetic targets for molecular breeding of cold-tolerant rice varieties.

Prey-mediated effects of mCry51Aa2-producing cotton on the predatory nontarget bug Orius majusculus(Reuter)

Genetically engineered(GE)cotton,MON 88702,is protected against cer-tain sucking pests,such as plant bugs and thrips,by producing mCry51Aa2,a mod-ified protein from Bacillus thuringiensis(Bt).Predatory pirate bugs(Orius spp.),natural enemies contributing to biological pest control,are also sensitive to the insecti-cidal protein when exposed continuously to high concentrations.We evaluated effects of MON 88702 on Orius majusculus when fed prey types with different mCry51Aa2 concen-trations.When neonates were provided exclusively Tetranychus urticae spider mites reared on MON 88702(high mCry51Aa2 content),adverse effects on predator survival and de-velopment were confirmed,compared with specimens fed prey from near-isogenic non-Bt cotton.When fed a mixture of T.urticae and Ephestia kuehniella eggs(mCry51Aa2-free),predator life table parameters were similar to the treatment where eggs were fed exclu-sively.When mCry51Aa2-containing spider mites were provided for a limited time at the beginning or the end of juvenile development,effects were less pronounced.While pirate bug nymphs showed similar consumption rates for prey from Bt and non-Bt cotton,choice experiments revealed a preference for E.kuehniella eggs over spider mites.Lepidopteran larvae(Spodoptera littoralis,high mCry51Aa2 content)or cotton aphids(Aphis gossypii,mCry51Aa2-free)reared on MON 88702 as alternative prey did not result in adverse ef-fects on O.majusculus.Our study suggests limited risk of mCry51Aa2-producing cotton for O.majusculus,because its sensitivity for the Bt protein is relatively low and its natural food consists of diverse prey species with varying concentrations of Bt protein.

Brazilian biosafety law and the new breeding technologies

Globally,the area of land cultivated with genetically modified(GM)crops has increased a thousand-fold over the last two decades.Although this technology has become important for food production,the regulatory frameworks that underpin these outcomes are based on a list of requirements for a risk assessment that differ from country to country.In recent years,policymakers have had the opportunity to learn from the controversies over transgenics to create effective regulatory milestones for emerging technologies,allowing them to reach their potential for a more sustainable agriculture,ensuring food security.In Brazil,Law No.11.105 of 24 March 2005 established a framework with four main organizations responsible for risk assessment and management.However,most of new breeding technologies did not exist at that time and were not considered in this law.In2016,Normative Resolution No.16 of the National Biosafety Technical Commission(CTNBio)was established to address this gap based on the evaluation of the products obtained through these techniques(termed Innovative Precision Improvement Techniques in the resolution),in a case-by-case consultation system.Briefly,if the product is designated to be a GM,the developer will have to go through the biosafety requirements and will be approved only after CTNBio risk assessment.If the product is designated not to be GM(for the purposes of the legislation),then it can be registered using the existing procedures.Currently,152 GM products are commercially approved in Brazil.In 2018,CTNBio assessed the first consultation on commercial release of plants generated using the new breeding technologies and has subsequently approved six products.It is expected that many institutions would be able to participate in Brazilian and world markets,developing and introducing new biotechnological solutions and products through a more sustainable approach and without facing public disapproval,a common issue for GM crops.

Recurrent breakdown and rebalance of segregation distortion in the genomes: battle for the transmission advantage

Mendel’s laws state that each of the two alleles would segregate during gamete formation and show the same transmission ratio in the next generation.However,an unexpected biased allele transmission was first detected in Drosophila a century ago,and was subsequently observed in other animals,plants,and microorganisms.Such segregation distortion(SD)shows substantial effects in population structure and fitness of the progenies,which would ultimately lead to reproductive isolation and speciation.Here,we trace the early investigations on the violation of Mendelian genetic principle,which appears as a wideexistence phenomenon rather than a case of exception.The occurence of SD in the whole genome was observed in a number of plant species at the single-and multi-locus level.Biased transmission ratio might occur at meiosis stage due to asymmetric movement of the chromosome;transmission ratio advantage is also caused by interaction and battle between the alleles from respective genomes at the genetic and molecular level.The origin of a SD system is likely to be determined by coevolution of the killer and protector via recurrent breakdown or rebalance loop.These updated understandings also promote genetic improvement of hybrid crops.

Evaluation and application of an efficient plant DNA extraction protocol for laboratory and field testing

Nucleic acids in plant tissue lysates can be captured quickly by a cellulose filter paper and prepared for amplification after a quick purification.In this study,a published filter paper strip method was modified by sticking the filter paper on a polyvinyl chloride resin(PVC)sheet.This modified method is named EZ-D,for EASY DNA extraction.Compared with the original cetyl trimethylammonium bromide(CTAB)method,DNA extracted by EZ-D is more efficient in polymerase chain reaction(PCR)amplification due to the more stable performance of the EZ-D stick.The EZ-D method is also faster,easier,and cheaper.PCR analyses showed that DNA extracted from several types of plant tissues by EZ-D was appropriate for specific identification of biological samples.A regular PCR reaction can detect the EZ-D-extracted DNA template at concentration as low as 0.1 ng/μL.Evaluation of the EZ-D showed that DNA extracts could be successfully amplified by PCR reaction for DNA fragments up to 3000 bp in length and up to 80%in GC content.EZ-D was successfully used for DNA extraction from a variety of plant species and plant tissues.Moreover,when EZ-D was combined with the loop-mediated isothermal amplification(LAMP)method,DNA identification of biological samples could be achieved without the need for specialized equipment.As an optimized DNA purification method,EZ-D shows great advantages in application and can be used widely in laboratories where equipment is limited and rapid results are required.

Reduced Mythimna separata infestation on Bt corn could benefit aphids

Use of genetically engineered plants that express insecticidal Cry proteins derived from Bacillus thuringiensis(Bt)have been proven efficacious for managing lepidopteran pests.However,in some cases herbivores that are not targeted by the Bt trait have increased in importance.It has been suggested that reduced caterpillar damage to Bt crops could lead to decreased levels of induced plant defensive compounds which might benefit other non-target herbivores.Here we investigated the potential effect of reduced damage by larvae of Mythimna separata on aphid populations in Bt corn.We compared the performance of Rhopalosiphum maidis feeding on non-Bt corn plants that had been infested by M.separata larvae or were uninfested.The results showed that caterpillar-infested corn plants significantly reduced the fitness of R.maidis leading to a prolonged nymphal development time,reduced adult longevity and fecundity compared to uninfested plants.Consequently,the population growth rate of corn aphids feeding on caterpillar-infested corn plants was significantly lower than on uninfested plants.As expected,the aphids performed significantly better on Lepidoptera-resistant Bt corn than on non-Bt corn when plants were infested with M.separata,since the caterpillars caused very little damage to the Bt plants.The current findings indicate that reduced M.separata infestation could benefit aphid development in Bt corn.Bt corn has the potential to be commercialized in China in the near future and aphids and other non-target pests should be monitored in the farming fields.