Transgenic Maize Lines Research Articles

Transgenic expression of Rubisco accumulation factor2 and Rubisco subunits increases photosynthesis and growth in maize.

Carbon assimilation by Rubisco is often a limitation to photosynthesis and therefore plant productivity. We have previously shown that transgenic co-expression of the Rubisco large (LS) and small (SS) subunits along with an essential Rubisco accumulation factor, Raf1, leads to faster growth, increased photosynthesis, and enhanced chilling tolerance in maize (Zea mays). Maize also requires Rubisco accumulation factor2 (Raf2) for full accumulation of Rubisco. Here we have analyzed transgenic maize lines with increased expression of Raf2 or Raf2 plus LS and SS. We show that increasing Raf2 expression alone had minor effects on photosynthesis, whereas expressing Raf2 with Rubisco subunits led to increased Rubisco content, more rapid carbon assimilation, and greater plant height, most notably in plants at least 6 weeks of age. The magnitude of the effects was similar to what was observed previously for expression of Raf1 together with Rubisco subunits. Taken together, this suggests that increasing the amount of either assembly factor with Rubisco subunits can independently enhance Rubisco abundance and some aspects of plant performance. These results could also imply either synergy or a degree of functional redundancy for Raf1 and Raf2, the latter of whose precise role in Rubisco assembly is currently unknown.

Overexpression of ZmSUS1 increased drought resistance of maize (Zea mays L.) by regulating sucrose metabolism and soluble sugar content.

ZmSUS1 improved drought tolerance of maize by regulating sucrose metabolism and increasing soluble sugar content, and endowing transgenic maize with higher relative water content and photosynthesis levels. Sucrose synthase (SUS), a key enzyme of sugar metabolism, plays an important role in the regulation of carbon partitioning in plant, and affects important agronomic traits and abiotic responses to adversity. However, the function of ZmSUS1 in plant drought tolerance is still unknown. In this study, the expression patterns of ZmSUS1 in different tissues and under drought stress were analyzed in maize (Zea mays L.). It was found that ZmSUS1 was highly expressed during kernel development but also in leaves and roots of maize, and ZmSUS1 was induced by drought stress. Homozygous transgenic maize lines overexpressing ZmSUS1 increased the content and activity of SUS under drought stress and exhibited higher relative water content, proline and abscisic acid content in leaves. Specifically, the net photosynthetic rate and the soluble sugar contents including sucrose, glucose, fructose and SUS decomposition products including UDP-glucose (UDP-G) and ADP-glucose (ADP-G) in transgenic plants were significantly improved after drought stress. RNA-seq analysis showed that overexpressing of ZmSUS1 mainly affected the expression level of carbon metabolism-related genes. Especially the expression level of sucrose metabolism-related genes including sucrose phosphatase gene (SPP), sucrose phosphate synthase gene (SPS) and invertase gene (INV) were significantly up-regulated in transgenic maize. Overall, these results suggested that ZmSUS1 improved drought tolerance by regulating sucrose metabolism and increasing the soluble sugar content, and endowing transgenic maize with higher relative water content and photosynthesis levels, which can serve as a new gene candidate for cultivating drought-resistant maize varieties.

Radiobiological studies on fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae)

Abstract The fall armyworm, Spodoptera frugiperda (JE Smith, 1797) is a notorious invasive pest causing significant economic damage to various crops. The extensive damage caused by this pest has created havoc in India and has become a nightmare for farmers. The management steps taken for controlling the pest have become futile. There are several instances depicting the failure of conventional management tactics, viz resistance against insecticides and transgenic maize lines paving the way for exploiting newer paradigms of pest management. Hence, a novel approach through the use of gamma irradiation against the pest was attempted. A dose-response trial encompassing doses from 50 to 200 Gy was employed to study the adverse effects of gamma irradiation on the biology of fall armyworm. The irradiated insects were crossed with their counterpart and the developmental profile of progeny was analysed. The obtained results were quite promising and showed a significant effect on the biology of the pest with progression of the irradiation dose. When females were exposed to irradiation and crossed with fertile counterparts, fecundity decreased with an increase in irradiation dose. A considerable increase in the egg, larval and pupal period was observed at 100 and 150 Gy. This decreased fecundity reduces the pest’s build-up in the field and the prolonged developmental period make the pest more prone to biotic and abiotic annihilation factors. Hence, the above-mentioned strategy has plausible applications in the near future and this tool can better be fitted into area-wide integrated pest management programmes.

The Transcription Factor ZmNAC89 Gene Is Involved in Salt Tolerance in Maize (Zea mays L.).

The NAC gene family has transcription factors specific to plants, which are involved in development and stress response and adaptation. In this study, ZmNAC89, an NAC gene in maize that plays a role in saline-alkaline tolerance, was isolated and characterized. ZmNAC89 was localized in the nucleus and had transcriptional activation activity during in vitro experiments. The expression of ZmNAC89 was strongly upregulated under saline-alkaline, drought and ABA treatments. Overexpression of the ZmNAC89 gene in transgenic Arabidopsis and maize enhanced salt tolerance at the seedling stage. Differentially expressed genes (DEGs) were then confirmed via RNA-sequencing analysis with the transgenic maize line. GO analyses showed that oxidation-reduction process-regulated genes were involved in ZmNAC89-mediated salt-alkaline stress. ZmNAC89 may regulate maize saline-alkali tolerance through the REDOX pathway and ABA signal transduction pathway. From 140 inbred maize lines, 20 haplotypes and 16 SNPs were found in the coding region of the ZmNAC89 gene, including the excellent haplotype HAP20. These results contribute to a better understanding of the response mechanism of maize to salt-alkali stress and marker-assisted selection during maize breeding.

Characterization of ZmPMP3g function in drought tolerance of maize

The genes enconding proteins containing plasma membrane proteolipid 3 (PMP3) domain are responsive to abiotic stresses, but their functions in maize drought tolerance remain largely unknown. In this study, the transgenic maize lines overexpressing maize ZmPMP3g gene were featured by enhanced drought tolerance; increases in total root length, activities of superoxide dismutase and catalase, and leaf water content; and decreases in leaf water potential, levels of O2−·and H2O2, and malondialdehyde content under drought. Under treatments with foliar spraying with abscisic acid (ABA), drought tolerance of both transgenic line Y7-1 overexpressing ZmPMP3g and wild type Ye478 was enhanced, of which Y7-1 showed an increased endogenous ABA and decreased endogenous gibberellin (GA) 1 (significantly) and GA3 (very slightly but not significantly) and Ye478 had a relatively lower ABA and no changes in GA1 and GA3. ZmPMP3g overexpression in Y7-1 affected the expression of multiple key transcription factor genes in ABA-dependent and -independent drought signaling pathways. These results indicate that ZmPMP3g overexpression plays a role in maize drought tolerance by harmonizing ABA-GA1-GA3 homeostasis/balance, improving root growth, enhancing antioxidant capacity, maintaining membrane lipid integrity, and regulating intracellular osmotic pressure. A working model on ABA-GA-ZmPMP3g was proposed and discussed.

Host-induced silencing of the CpCHI gene resulted in developmental abnormalities and mortality in maize stem borer (Chilo partellus).

RNAi-based insecticides for crop protection have witnessed rapid improvement over the years. However, their potential to efficiently control maize stem borer (Chilo partellus) pests has remained underexplored. In this study, double-stranded C. partellus chitinase (dsCHI) toxicity was investigated in C. partellus larvae. Furthermore, we developed transgenic maize lines expressing dsRNA targeted against C. partellus chitinase transcripts and performed detached leaf insect feeding bioassays. Our results revealed that C. partellus chitinase transcript expression was significantly downregulated by 57% and 82% in the larvae. Larvae exhibited various phenotypic distortion levels across developmental stages, and 53% mortality occurred in transgenic fed larvae compared to those fed on nontransgenic leaves. In conclusion, we have identified the C. partellus chitinase gene as a potential target for RNAi-mediated control and demonstrated that oral delivery via bacteria and plant-mediated delivery are viable means of achieving C. partellus RNAi-mediated control.

Adaptation analysis of insect-resistant transgenic line after introducing mcry1F gene in maize

The ability to adapt, survive, and compete with weeds of transgenic plants is the necessary evaluation content to release transgenic lines in target regions. We compared weediness and agronomic traits of transgenic maize lines G1F-8 and G1F-19 carrying the mcry1F gene with their near-isogenic maize inbred line Zheng 58 in the wasteland and cultivated field under natural conditions for two consecutive years. The results showed that there was no significant difference identified in the species, quantity, and relative coverage ratio (RCR) of weeds between fields with G1F-8, G1F-19, and Zheng 58, regardless of the sowing pattern in the wasteland. Compared with the vigour of weeds, none of G1F-8, G1F-19, and Zheng 58 showed survival advantages, and all showed weak growth potential with no final grain yield. Meanwhile, no volunteer seedlings were found upon investigation in the following year. The simulated seed overwintering experiment in the wasteland further showed that the three kinds of maize could not germinate in the second year. In cultivated land, G1F-8 and G1F-19 had the same growth stages, plant height, and RCR as Zheng 58 throughout two years. In conclusion, the transgenic lines G1F-8 and G1F-19 exhibited no adaptability risk in Gongzhuling, Jilin, China.

Differential assembly of root-associated bacterial and fungal communities of a dual transgenic insect-resistant maize line at different host niches and different growth stages.

Transgenic technology has been widely applied to crop development, with genetically modified (GM) maize being the world’s second-largest GM crop. Despite the fact that rhizosphere bacterial and fungal populations are critical regulators of plant performance, few studies have evaluated the influence of GM maize on these communities. Plant materials used in this study included the control maize line B73 and the mcry1Ab and mcry2Ab dual transgenic insect-resistant maize line 2A-7. The plants and soils samples were sampled at three growth stages (jointing, flowering, and maturing stages), and the sampling compartments from the outside to the inside of the root are surrounding soil (SS), rhizospheric soil (RS), and intact root (RT), respectively. In this study, the results of alpha diversity revealed that from the outside to the inside of the root, the community richness and diversity declined while community coverage increased. Morever, the different host niches of maize rhizosphere and maize development stages influenced beta diversity according to statistical analysis. The GM maize line 2A-7 had no significant influence on the composition of microbial communities when compared to B73. Compared to RS and SS, the host niche RT tended to deplete Chloroflexi, Gemmatimonadetes and Mortierellomycota at phylum level. Nitrogen-fixation bacteria Pseudomonas, Herbaspirillum huttiense, Rhizobium leguminosarum, and Sphingomonas azotifigens were found to be enriched in the niche RT in comparison to RS and SS, whilst Bacillus was found to be increased and Stenotrophomonas was found to be decreased at the maturing stage as compared to jointing and flowering stages. The nitrogen fixation protein FixH (clusters of orthologous groups, COG5456), was found to be abundant in RT. Furthermore, the pathogen fungus that causes maize stalk rot, Gaeumannomyces radicicola, was found to be abundant in RT, while the beneficial fungus Mortierella hyalina was found to be depleted in RT. Lastly, the abundance of G. radicicola gradually increased during the development of maize. In conclusion, the host niches throughout the soil-plant continuum rather than the Bt insect-resistant gene or Bt protein secretion were primarily responsible for the differential assembly of root-associated microbial communities in GM maize, which provides the theoretical basis for ecological agriculture.

The mycorrhiza-specific ammonium transporter ZmAMT3;1 mediates mycorrhiza-dependent nitrogen uptake in maize roots.

Most plant species can form symbioses with arbuscular mycorrhizal fungi (AMFs), which may enhance the host plant's acquisition of soil nutrients. In contrast to phosphorus nutrition, the molecular mechanism of mycorrhizal nitrogen (N) uptake remains largely unknown, and its physiological relevance is unclear. Here, we identified a gene encoding an AMF-inducible ammonium transporter, ZmAMT3;1, in maize (Zea mays) roots. ZmAMT3;1 was specifically expressed in arbuscule-containing cortical cells and the encoded protein was localized at the peri-arbuscular membrane. Functional analysis in yeast and Xenopus oocytes indicated that ZmAMT3;1 mediated high-affinity ammonium transport, with the substrate NH4+ being accessed, but likely translocating uncharged NH3. Phosphorylation of ZmAMT3;1 at the C-terminus suppressed transport activity. Using ZmAMT3;1-RNAi transgenic maize lines grown in compartmented pot experiments, we demonstrated that substantial quantities of N were transferred from AMF to plants, and 68%-74% of this capacity was conferred by ZmAMT3;1. Under field conditions, the ZmAMT3;1-dependent mycorrhizal N pathway contributed >30% of postsilking N uptake. Furthermore, AMFs downregulated ZmAMT1;1a and ZmAMT1;3 protein abundance and transport activities expressed in the root epidermis, suggesting a trade-off between mycorrhizal and direct root N-uptake pathways. Taken together, our results provide a comprehensive understanding of mycorrhiza-dependent N uptake in maize and present a promising approach to improve N-acquisition efficiency via plant-microbe interactions.

Overexpression of ZmIPT2 gene delays leaf senescence and improves grain yield in maize.

Cytokinins (CTKs) are a major phytohormone group that are significant in the promotion of cellular division, growth, and divergence. Isopentenyl transferase (IPT) regulates a rate-limiting step in plant CTK synthesis, promotes the synthesis of isopentenyl adenonucleotides from 5-AMP and isopentenyl pyrophosphate, and then converts both these chemicals into various CTKs. Here, the full-length cDNA of ZmIPT2, which encodes 322 amino acids, was isolated and was introduced into a maize inbred line by Agrobacterium-mediated transformation. In both controlled environments and field experiments, the overexpression of ZmIPT2 gene in the transformed plants delayed leaf senescence. Compared to the receptor line, the transgenic maize lines retained higher chlorophyll levels, photosynthetic rates, and cytokinin content for an extended period of time, and produced significantly higher grain yield by a margin of 17.71–20.29% under normal field planting conditions. Subsequently, ten possible genes that interacted with ZmIPT2 were analyzed by qRT-PCR, showing that the expression pattern of GRMZM2G022904 was consistent with ZmIPT2 expression. Through comprehensive analysis, we screened for transgenic lines with stable inheritance of ZmIPT2 gene, clear functional efficiency, and significant yield improvement, in order to provide theoretical basis and material support for the breeding of new high-yield transgenic maize varieties.

Improvement of cold tolerance in maize (Zea mays L.) using Agrobacterium-mediated transformation of ZmSAMDC gene

ABSTRACT Maize (Zea mays L.) is a food crop sensitive to low temperatures. As one of the abiotic stress hazards, low temperatures seriously affect the yield of maize. However, the genetic basis of low-temperature adaptation in maize is still poorly understood. In this study, maize S-adenosylmethionine decarboxylase (SAMDC) was localized to the nucleus. We used Agrobacterium-mediated transformation technology to introduce the SAMDC gene into an excellent maize inbred line variety GSH9901 and produced a cold-tolerant transgenic maize line. After three years of single-field experiments, the contents of polyamines (PAs), proline (Pro), malondialdehyde (MDA), antioxidant enzymes and ascorbate peroxidases (APXs) in the leaves of the transgenic maize plants overexpressing the SAMDC gene significantly increased, and the expression of elevated CBF and cold-responsive genes effectively increased. The agronomic traits of the maize overexpressing the SAMDC gene changed, and the yield traits significantly improved. However, no significant changes were found in plant height, ear length, and shaft thickness. Therefore, SAMDC enzymes can effectively improve the cold tolerance of maize.

Expressing the sunflower transcription factor HaHB11 in maize improves waterlogging and defoliation tolerance.

The sunflower (Helianthus annuus) transcription factor HaHB11 (H. annuus Homeobox 11) belongs to the homeodomain-leucine zipper family and confers improved yield to maize (Zea mays) hybrids (HiII × B73) and lines. Here we report that transgenic maize lines expressing HaHB11 exhibited better performance under waterlogging, both in greenhouse and field trials carried out during three growth cycles. Transgenic plants had increased chlorophyll content, wider stems, more nodal roots, greater total aerial biomass, a higher harvest index, and increased plant grain yield. Under severe defoliation caused by a windstorm during flowering, transgenic genotypes were able to set more grains than controls. This response was confirmed in controlled defoliation assays. Hybrids generated by crossing B73 HaHB11 lines with the contrasting Mo17 lines were also tested in the field and exhibited the same beneficial traits as the parental lines, compared with their respective controls. Moreover, they were less penalized by stress than commercial hybrids. Waterlogging tolerance increased via improvement of the root system, including more xylem vessels, reduced tissue damage, less superoxide accumulation, and altered carbohydrate metabolism. Multivariate analyses corroborated the robustness of the differential traits observed. Furthermore, canopy spectral reflectance data, computing 29 vegetation indices associated with biomass, chlorophyll, and abiotic stress, helped to distinguish genotypes as well as their growing conditions. Altogether the results reported here indicate that this sunflower gene constitutes a suitable tool to improve maize plants for environments prone to waterlogging and/or wind defoliation.

Elevated CO2 Differentially Mitigated Oxidative Stress Induced by Indium Oxide Nanoparticles in Young and Old Leaves of C3 and C4 Crops.

Soil contamination with indium (In) oxide nanoparticles (In2O3-NPs) threatens plant growth and development. However, their toxicity in plants under ambient (aCO2) and elevated (eCO2) conditions is scarcely studied. To this end, this study was conducted to investigate In2O3-NPs toxicity in the young and old leaves of C3 (barley) and C4 (maize) plants and to understand the mechanisms underlying the stress mitigating impact of eCO2. Treatment of C3 and C4 plants with In2O3-NPs significantly reduced growth and photosynthesis, induced oxidative damage (H2O2, lipid peroxidation), and impaired P and Fe homeostasis, particularly in the young leaves of C4 plants. On the other hand, this phytotoxic hazard was mitigated by eCO2 which improved both C3 and C4 growth, decreased In accumulation and increased phosphorus (P) and iron (Fe) uptake, particularly in the young leaves of C4 plants. Moreover, the improved photosynthesis by eCO2 accordingly enhanced carbon availability under the challenge of In2O3-NPs that were directed to the elevated production of metabolites involved in antioxidant and detoxification systems. Our physiological and biochemical analyses implicated the role of the antioxidant defenses, including superoxide dismutase (SOD) in stress mitigation under eCO2. This was validated by studying the effect of In2O3-stress on a transgenic maize line (TG) constitutively overexpressing the AtFeSOD gene and its wild type (WT). Although it did not alter In accumulation, the TG plants showed improved growth and photosynthesis and reduced oxidative damage. Overall, this work demonstrated that C3 was more sensitive to In2O3-NPs stress; however, C4 plants were more responsive to eCO2. Moreover, it demonstrated the role of SOD in determining the hazardous effect of In2O3-NPs.

Enzymatic degradation is an effective means to reduce aflatoxin contamination in maize

BackgroundAflatoxins are carcinogenic compounds produced by certain species of Aspergillus fungi. The consumption of crops contaminated with this toxin cause serious detrimental health effects, including death, in both livestock and humans. As a consequence, both the detection and quantification of this toxin in food/feed items is tightly regulated with crops exceeding the allowed limits eliminated from food chains. Globally, this toxin causes massive agricultural and economic losses each year.ResultsIn this paper we investigate the feasibility of using an aflatoxin-degrading enzyme strategy to reduce/eliminate aflatoxin loads in developing maize kernels. We used an endoplasmic reticulum (ER) targeted sub-cellular compartmentalization stabilizing strategy to accumulate an aflatoxin-degrading enzyme isolated from the edible Honey mushroom Armillariella tabescens and expressed it in embryo tissue in developing maize kernels. Three transgenic maize lines that were determined to be expressing the aflatoxin-degrading enzyme both at the RNA and protein level, were challenged with the aflatoxin-producing strain Aspergillus flavus AF13 and shown to accumulate non-detectable levels of aflatoxin at 14-days post-infection and significantly reduced levels of aflatoxin at 30-days post-infection compared to nontransgenic control Aspergillus-challenged samples.ConclusionsThe expression of an aflatoxin-degrading enzyme in developing maize kernels was shown to be an effective means to control aflatoxin in maize in pre-harvest conditions. This aflatoxin-degradation strategy could play a significant role in the enhancement of both US and global food security and sustainability.

Differences in Cadmium Accumulation, Detoxification and Antioxidant Defenses between Contrasting Maize Cultivars Implicate a Role of Superoxide Dismutase in Cd Tolerance.

Cadmium (Cd), a readily absorbed and translocated toxic heavy metal, inhibits plant growth, interrupts metabolic homeostasis and induces oxidative damage. Responses towards Cd-stress differ among plant cultivars, and the complex integrated relationships between Cd accumulation, detoxification mechanisms and antioxidant defenses still need to be unraveled. To this end, 12 Egyptian maize cultivars were grown under Cd-stress to test their Cd-stress tolerance. Out of these cultivars, tolerant (TWC360 and TWC321), moderately sensitive (TWC324) and sensitive (SC128) cultivars were selected, and we determined their response to Cd in terms of biomass, Cd accumulation and antioxidant defense system. The reduction in biomass was highly obvious in sensitive cultivars, while TWC360 and TWC321 showed high Cd-tolerance. The cultivar TWC321 showed lower Cd uptake concurrently with an enhanced antioxidant defense system. Interestingly, TWC360 accumulated more Cd in the shoot, accompanied with increased Cd detoxification and sequestration. A principal component analysis revealed a clear separation between the sensitive and tolerant cultivars with significance of the antioxidant defenses, including superoxide dismutase (SOD). To confirm the involvement of SOD in Cd-tolerance, we studied the effect of Cd-stress on a transgenic maize line (TG) constitutively overexpressing AtFeSOD gene in comparison to its wild type (WT). Compared to their WT, the TG plants showed less Cd accumulation and improved growth, physiology, antioxidant and detoxification systems. These results demonstrate the role of SOD in determining Cd-tolerance.

Gene Transformation by Chitosan Nanoparticle to Enhance Fatty Acid Production in Zea mays (L.)

Zea mays is an important crop and an essential source of fatty acids. Hence, increasing and adding new fatty acids led to the enhancement of these properties. Transformation of external Acetyl-CoA gene (Aco) can enhance fatty acid components, as ACo is expressed into Acetyl-CoA carboxylase (ACCase) enzyme, which is the first essential step in the fatty acid production process. Chitosan nanoparticles are safe and fast polymer nanoparticles that are applied for gene transformation. Conventional PCR was performed for the detection of the ACo gene in both transgenic and nontransgenic maize lines. The results confirm the presence of the gene in the transgenic lines and absence in non-transgenic lines. The Gas chromatography-mass spectrometry (GC-MS) analysis for fatty acid contents in transgenic and non-transgenic maize lines showed an increase in fatty acid contents in transgenic lines compared to non-transgenic ones. Besides, the transgenic maize’s lines produced extra new fatty acids not found in non-transgenic ones.

Using Combined Methods of Genetic Mapping and Nanopore-Based Sequencing Technology to Analyze the Insertion Positions of G10evo-EPSPS and Cry1Ab/Cry2Aj Transgenes in Maize.

The insertion position of the exogenous fragment sequence in a genetically modified organism (GMO) is important for the safety assessment and labeling of GMOs. SK12-5 is a newly developed transgenic maize line transformed with two trait genes [i.e., G10evo-5-enolpyrul-shikimate-3-phosphate synthase (EPSPS) and Cry1Ab/Cry2Aj] that was recently approved for commercial use in China. In this study, we tried to determine the insertion position of the exogenous fragment for SK12-5. The transgene–host left border and right border integration junctions were obtained from SK12-5 genomic DNA by using the thermal asymmetric interlaced polymerase chain reaction (TAIL-PCR) and next-generation Illumina sequencing technology. However, a Basic Local Alignment Search Tool (BLAST) analysis revealed that the flanking sequences in the maize genome are unspecific and that the insertion position is located in a repetitive sequence area in the maize genome. To locate the fine-scale insertion position in SK12-5, we combined the methods of genetic mapping and nanopore-based sequencing technology. From a classical bulked-segregant analysis (BSA), the insertion position in SK12-5 was mapped onto Bin9.03 of chromosome 9 between the simple sequence repeat (SSR) markers umc2337 and umc1743 (26,822,048–100,724,531 bp). The nanopore sequencing results uncovered 10 reads for which one end was mapped onto the vector and the other end was mapped onto the maize genome. These observations indicated that the exogenous T-DNA fragments were putatively integrated at the position from 82,329,568 to 82,379,296 bp of chromosome 9 in the transgenic maize SK12-5. This study is helpful for the safety assessment of the novel transgenic maize SK12-5 and shows that the combined method of genetic mapping and the nanopore-based sequencing technology will be a useful approach for identifying the insertion positions of transgenic sequences in other GM plants with relatively large and complex genomes.

Integrated proteomics and metabolomics analysis of transgenic and gene-stacked maize line seeds

ABSTRACT Unintended effects of genetically modified (GM) crops may pose safety issues. Omics techniques provide researchers with useful tools to assess such unintended effects. Proteomics and metabolomics analyses were performed for three GM maize varieties, 2A-7, CC-2, and 2A-7×CC-2 stacked transgenic maize, and the corresponding non-GM parent Zheng58. Proteomics revealed 120, 271 and 135 maize differentially expressed proteins (DEPs) in the 2A-7/Zheng58, CC-2/Zheng58 and 2A-7×CC-2/Zheng58 comparisons, respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that most DEPs participated in metabolic pathways and the biosynthesis of secondary metabolite. Metabolomics revealed 179, 135 and 131 differentially accumulated metabolites (DAMs) in the 2A-7/Zheng58, CC-2/Zheng58 and 2A-7×CC-2/Zheng58 comparisons, respectively. Based on KEGG enrichment analysis, most DAMs are involved in the biosynthesis of secondary metabolite and metabolic pathways. According to integrated proteomics and metabolomics analysis, the introduction of exogenous EPSPS did not affect the expression levels of six other enzymes or the abundance of seven metabolites involved in the shikimic acid pathway in CC-2 and 2A-7×CC-2 seeds. Six co-DEPs annotated by integrated proteomics and metabolomics pathway analysis were further analyzed by qRT-PCR. This study successfully employed integrated proteomic and metabolomic technology to assess unintended changes in maize varieties. The results suggest that GM and gene stacking do not cause significantly unintended effects.

ANALYSIS of the Distribution of the Western Corn Rootworm (Diabrotica Virgifera Virgifera le Conte) in Agrocenoses of Cherkasy Region and Determination of Resistance of Individual Maize Hybrids to Damage

Introduction.The expansion of the western corn beetle (Diabrotica virgifera virgifera Le Conte) in Ukraine in recent years has complicated the quarantine situation. In the area where the pest is widespread, significant losses of corn were found, especially when it is grown in monoculture. To reduce the number of pests and reduce its harmfulness, it is enough to follow the rotation of crops: the return of corn to the field in three or four years.But growing corn in a two-field crop rotation leads to rapid adaptation of the pest. Attempts by genetic engineering to obtain transgenic maize lines resistant to diabrotica have not yet yielded the expected results. Genetically modified plants are effective only for regulating the number of adults. The main prerequisite of any plant protection system is modern phytosanitary monitoring and forecast of the Серія «Біологічні науки», 202136spread of the western corn beetle, which should be a system of collection, accumulation, analysis and use of phytosanitary, in particular, quarantine information.Purpose.Of the work is to analyze the distribution of phytophagous in the conditions of Cherkasy region and protection of the resistance of maize hybrids that have passed the state variety test to western corn rootworm.Methods.Field, accounting, laboratory and static methods were used in the research.Results.The analysis of the areas inhabited by the western corn beetle of the Cherkasy region in 2019 shows,that only in seven districts of the region outbreaks of western corn beetle infection were detected, however, the natural and climatic conditions of our region are favorable for the spread of this dangerous quarantine pest, which necessitates constant monitoring of outbreaks. During the three-year period of our observations, the phytophagous inhabited fields adjacent to river floodplains and lowlands. The development of the western corn beetle is closely related to the temperature conditions of Cherkasy region.During our research it was established that the beginning of flight of beetles occurred at the sum of effective temperatures (∑ t) above 15 ºС in the range of 750-850 ºС. The stages of passage of separate phases of ontogenesis of the western corn beetle in the territory of Cherkasy region according to temperature indicators allow us to effectively plan pest monitoring and quarantine extermination measures. Laboratory evaluation of 25 maize hybrids for resistance to the western maize beetle. Of all the studied maize hybrids, 1 hybrid was highly resistant, 3 hybrids were resistant.Originality. The territory of Cherkasy region is analyzed regarding the distribution of the western corn rootworm. 25 maize hybrids of different maturation periods were evaluated for resistance to the western maize beetle, 8 hybrids were selected for practical use on the basis of high level of stability and the highest yield.Conclusions. Thus, the Analysis of the territories of Cherkasy region in 2018-2020 on the distribution of western corn beetle (Diabroticavirgifera virgifera Le Conte) shows that the pest was found in 7 districts: Zvenigorod, Korsun-Shevchenko, Monastyryshche, Talniv, Uman, KhShpolyansky. The most resistant to damage by the western corn beetle are early-maturing hybrids of corn (FAO 100-199) –Dolphin, DKS 3476, ДМС 1915.Late hybrids (FAO 500-600) are unstable –DM Native, Kharkiv 43 M (Donor M), Kharkiv 45 M (Industry M), Lyubava MV, Standard. It was determined the lowest damage to plant seedlings by the western corn rootworm in the early stages of sowing corn –5% in the hybrid Sensor. The most damaged plants at late sowing stages. Varieties LCA 4010 and DM Sunrise were damaged by 22,8% and 21,7% respectively.Key words:FAO maize hybrids (100-200); crop rotation; phytosanitary monitoring, the number of pests.

Drought tolerance in high-generation transgenic maize inbred lines overexpressing the betaine aldehyde dehydrogenase gene

Abiotic stress such as drought seriously endangers maize growth and production. Glycine betaine (GB) accumulation in transgenic crops following heterologous overexpression of the BADH gene has been shown to dramatically improve the tolerance to salt, cold, and oxidative stresses, but it is unclear if GB accumulation leads to improved drought tolerance of maize. In this study, we analyzed the drought tolerance of high-generation BADH transgenic maize inbred lines at different growth stages using the hyperosmotic solution and water-withholding methods. Molecular detection revealed that exogenous BADH was successfully introduced into the maize plant genome and overexpressed in three transgenic maize inbred lines. Under osmotic stress, transgenic maize held better germination ability than the unmodified Dan988 (WT) line. In addition, transgenic maize contained higher levels of antioxidant enzymes and osmotic regulatory substances compared with WT, and thus accumulated less harmful substances and this alleviated the negative effects of drought. We used the membership function method to quantify the drought tolerance and found that Dan988-BADH-4 showed the best tolerance, followed by Dan988-BADH-2 and Dan988-BADH-1 while WT ranked lowest. This was consistent with the statistical analysis of the experiments. From the indoor and field survey, we observed that the agronomic traits of transgenic maize were not affected by the overexpression of BADH. In conclusion, BADH overexpression in maize is beneficial for drought tolerance and the three transgenic maize lines can be used for further breeding experiments.