Agrobacterium-mediated Gene Transfer Research Articles

Optimization of stable genetic transformation protocol in castor (Ricinus communis L. cv. TMV 5) using beta glucuronidase reporter gene for pioneer of desirable genes

The simple and stable protocol was standardised for castor (Ricinus communis L. cv. TMV 5) genetic transformation using Agrobacterium tumefaciens strain LBA4404 harbouring the binary plasmid pBAL2 (18.8 kb). Cotyledonary nodes from ten days old, in vivo seedlings were utilized as target cells for Agrobacterium mediated transformation. Explant pre-culture studies were carried out at 2, 4, 6, 8, 10 and 12 day intervals. The 4th day old explants cultivated on mMS medium (MS medium+B5 Vitamins) using plant growth regulators had the highest response percentage (50.6%). Kanamycin (0-175 mg/L) and Hygromycin (0-13 mg/L) sensitivity in well-developed shoots was investigated. Of the two antibiotics, Kanamycin 50 mg/L and Hygromycin 3 mg/L was found optimum. Different levels of acetosyringone (0-200 mg/L) were used in the co-cultivation medium to study the transformation efficiency of castor. Among the different concentrations, maximum number of explants showed GUS expression at 100 mg/L of acetosyringone in the co-cultivation medium at 2 days of co-cultivation period and the Cotyledonary node produced multiple shoots development and plantlet establishment in 0.3 mg/L TDZ, 0.6 mg/L PF-68, kanamycin 50 mg/L, 0.3 mg/L GA3, 1.5 mg/L IBA and 0.6 mg/L AgNO3. The rooted shoots were successfully acclimatized. Histochemical GUS assay was used to monitor T-DNA delivery into the target cells. PCR and Southern hybridization were used to confirm the transformants with the NPT II and GUS gene. A very high frequency (29.3%) of β-glucuronidase (GUS) gene expression was obtained through Agrobacterium-mediated gene transfer into cotyledonary node explants of Castor. The standardized protocol would be useful for Agrobacterium-mediated genetic transformation of Cator with desirable gene of agronomic importance.

Intragenic Agrobacterium-mediated gene transfer mimics micro-translocations without foreign DNA

Main conclusionAgrobacterium-mediated transformation of Nicotiana tabacum, using an intragenic T-DNA region derived entirely from the N. tabacum genome, results in the equivalence of micro-translocations within genomes.Intragenic Agrobacterium-mediated gene transfer was achieved in Nicotiana tabacum using a T-DNA composed entirely of N. tabacum DNA, including T-DNA borders and the acetohydroxyacid synthase gene conferring resistance to sulfonylurea herbicides. Genomic analysis of a resulting plant, with single locus inheritance of herbicide resistance, identified a single insertion of the intragenic T-DNA on chromosome 5. The insertion event was composed of three N. tabacum DNA fragments from other chromosomes, as assembled on the T-DNA vector. This validates that intragenic transformation of plants can mimic micro-translocations within genomes, with the absence of foreign DNA.

Somatic Embryogenesis and Agrobacterium-Mediated Gene Transfer Procedures in Chilean Temperate Japonica Rice Varieties for Precision Breeding

Rice (Oryza sativa) varieties are generated through breeding programs focused on local requirements. In Chile, the southernmost rice producer, rice productivity relies on the use and generation of temperate japonica germplasms, which need to be adapted to the intensifying effects of climate change. Advanced biotechnological tools can contribute to these breeding programs; new technologies associated with precision breeding, including gene editing, rely on procedures such as regeneration and gene transfer. In this study, the local rice varieties Platino, Cuarzo, Esmeralda, and Zafiro were evaluated for somatic embryogenesis potential using a process that involved the combined use of auxins and cytokinins. An auxin-based (2,4-D) general medium (2N6) allowed for the induction of embryogenic masses in all the genotypes. After induction, masses required culturing either in N6R (kinetin; Platino) or N6RN (BAP, kinetin, IBA, and 2,4-D; Cuarzo, Esmeralda, and Zafiro) to yield whole plants using regeneration medium (N6F, no hormone). The sprouting rates indicated Platino as the most responsive genotype; for this reason, this variety was evaluated for gene transfer. Fifteen-day-old embryo masses were assayed for Agrobacterium-mediated transformation using the bacterial strain EHA105 harboring pFLC-Myb/HPT/GFP, a modified T-DNA vector harboring a geminivirus-derived replicon. The vector included the green fluorescent protein reporter gene, allowing for continuous traceability. Reporter mRNA was produced as early as 3 d after agroinfiltration, and stable expression of the protein was observed along the complete process. These achievements enable further biotechnological steps in these and other genotypes from our breeding program.

Natural transformants of Camellia section Thea

Horizontal gene transfer (HGT) plays an important role in plant evolution and plant development. Agrobacterium-mediated gene transfer leads to the formation of crown galls or hairy roots, due to expression of transferred T-DNA genes. Spontaneous regeneration of transformed cells can produce natural transformants carrying cellular T-DNA (cT-DNA) sequences of bacterial origin. HGT from Agrobacterium to dicots is remarkably widespread. The production of naturally genome modified plants could play a role in plant evolution and environment.
 Among these natural GMOs (nGMOs) there are the tea plants. Camellia sinensis var. sinensis cv. Shuchazao contains a single 5.5 kb cT-DNA fragment organized as imperfect inverted repeat with three inactive genes. 142 Camellia accessions, belonging to 10 of 11 species of the section Thea, were studied for the presence of cT-DNA alleles. All of them contain the cT-DNA insert, indicating that they are resulted from the single transformed event. Allele phasing showed that 82 accessions were heterozygous for T-DNA alleles, 60 others were homozygous. A phylogenetic analysis of all found alleles showed existence of two separate groups of them, further divided into subgroups. The alleles of the different Camellia species were distributed mosaically over groups, and different species showed very similar T-DNA alleles. This indicates that the taxonomy of Thea requires revision. The nucleotide divergence of the imperfect cT-DNA repeats indicates that the age of cT-DNA insertion is about 15 mya, which is earlier then emergence of section Thea [1]. We present a working model for the origin and evolution of nGMO plants derived from allogamous transformants.

New cellular T-DNAs in naturally transgenic plants

Naturally transgenic plants represent the result of Agrobacterium-mediated gene transfer. T-DNA of soil bacteria Agrobacterium integrated into plants genome is called cellular T-DNA (cT-DNA) [1]. Today, more than 50 species of naturally transgenic plants, or natural GMO (nGMO) are known [2, 3]. The function of cT-DNA in plants remains unknown. It is assumed that the fixation of transgenes could give plants different selective advantages depending on which genes had been integrated into the plant [4]. In order to clarify this issue, it is necessary to study more naturally transgenic plants. Until recently, the list of nGM plants contained less than 2 dozen species, but a search through genomic and transriptomic sequencing data made it possible to more than double this list [2]. In this work, we used the same approach, looking for cT-DNA genes in whole genome sequencing data that have appeared in the NCBI WGS since 2021. We found 14 new species of naturally transgenic plants, among which the most extended cT-DNAs were found in Triadica sebifera, Lonicera japonica, and Lonicera maackii. The cT-DNAs in these species are organized as imperfect inverted repeats. In the genomes of the species Paulownia fortunei, Apocynum venetum, Elaeagnus angustifolia, Erythroxylum havanense, E. densum, E. daphnites, E. cataractarum, Ceriops decandra, Camellia oleifera, Silene uniflora, short cT-DNAs containing only opine synthesis genes were found. We also estimated the approximate age of the cT-DNAs. The first described examples date back to the Late Paleogene, and the process continues to the present. Thus, we can conclude that natural GMOs are a widespread phenomenon, many aspects of which remain unclear, requiring additional research on the topic.
 The article was made with support of the Ministry of Science and Higher Education of the Russian Federation in accordance with agreement No. 075-15-2022-322 dated 22.04.2022 on providing a grant in the form of subsidies from the federal budget of the Russian Federation. The grant was provided for state support for the creation and development of a world-class scientific center, Agrotechnologies for the Future.

Unintended Genomic Outcomes in Current and Next Generation GM Techniques: A Systematic Review.

Classical genetic engineering and new genome editing techniques, especially the CRISPR/Cas technology, increase the possibilities for modifying the genetic material in organisms. These technologies have the potential to provide novel agricultural traits, including modified microorganisms and environmental applications. However, legitimate safety concerns arise from the unintended genetic modifications (GM) that have been reported as side-effects of such techniques. Here, we systematically review the scientific literature for studies that have investigated unintended genomic alterations in plants modified by the following GM techniques: Agrobacterium tumefaciens-mediated gene transfer, biolistic bombardment, and CRISPR-Cas9 delivered via Agrobacterium-mediated gene transfer (DNA-based), biolistic bombardment (DNA-based) and as ribonucleoprotein complexes (RNPs). The results of our literature review show that the impact of such techniques in host genomes varies from small nucleotide polymorphisms to large genomic variation, such as segmental duplication, chromosome truncation, trisomy, chromothripsis, breakage fusion bridge, including large rearrangements of DNA vector-backbone sequences. We have also reviewed the type of analytical method applied to investigate the genomic alterations and found that only five articles used whole genome sequencing in their analysis methods. In addition, larger structural variations detected in some studies would not be possible without long-read sequencing strategies, which shows a potential underestimation of such effects in the literature. As new technologies are constantly evolving, a more thorough examination of prospective analytical methods should be conducted in the future. This will provide regulators working in the field of genetically modified and gene-edited organisms with valuable information on the ability to detect and identify genomic interventions.

Investigation of factors in improving Agrobacterium-mediated gene transfer in Ruellia tuberosa L. and evaluation of α-glucosidase inhibitory activity in established hairy roots

Ruellia tuberosa (family Acanthaceae) is widely known in traditional medicine in Asian countries for the treatment of diabetes and other diseases. Its roots were demonstrated to possess a hypoglycemic ability in diabetic animal models. In this study, an original induced procedure was investigated to establish hairy root (HR) from R. tuberosa. With the aim of increasing the transformation rate, some induced factors (acetosyringone (AS) dosage, type of explant, age, infection time, bacterial density, co-cultivation duration) were individually examined. As a result, an improved procedure was implemented: ten-day-old in vitro cotyledon explants were injured and then immersed in the bacterial suspension (OD600 nm = 0.4) added 200 µM AS during 10 min. The infected explants were co-cultivated for 4 days in the Murashige & Skoog (MS) medium before transferring to the medium containing cefotaxime for bacterial elimination. After thirty days of culture, the improved procedure revealed a synergistic effect by enhancing the rooting rate and number of secondary roots per explant up to 4.4- and 8.0-fold, respectively, in comparison with the original procedure. The R. tuberosa HR was then cultured in liquid MS medium and achieved the highest biomass production at the late exponential growth phase (3rd week). Its ethanol extract was also higher 2.0-fold in α-glucosidase inhibitory activity than that of the natural root. In conclusion, the α-glucosidase inhibitory activity of HR inducing by the improved procedure may offer an effective and reliable substitute for the utilization of this herbal plant.

Target Lines for in Planta Gene Stacking in Japonica Rice.

The clustering of transgenes at a chromosome location minimizes the number of segregating loci that needs to be introgressed to field cultivars. Transgenes could be efficiently stacked through site-specific recombination and a recombinase-mediated in planta gene stacking process was described previously in tobacco based on the Mycobacteriophage Bxb1 site-specific integration system. Since this process requires a recombination site in the genome, this work describes the generation of target sites in the Japonica rice genome. Agrobacterium-mediated gene transfer yielded ~4000 random-insertion lines. Seven lines met the criteria of being single copy, not close to a centromere, not inserted within or close to a known gene or repetitive DNA, having precise recombination site sequences on both ends, and able to express the reporter gene. Each target line tested was able to accept the site-specific integration of a new gfp-containing plasmid and in three of those lines, we regenerated fertile plants. These target lines could be used as foundation lines for stacking new traits into Japonica rice.

Development of an Efficient Genetic Transformation Method for the Varietal Improvement of Simarouba Glauca Dc

The genetic transformation of Simarouba glauca will help researchers across the globe in developing high medicinal value and high biomass varieties in a short period. Although genetic transformation methods have been trailed by many research groups for several years, the variation in transformation efficiency and difficulties in handling tissue culture plantlets made it difficult to optimize a reliable protocol. In this study, we established an alternative protocol of genetic transformation by introducing GUS Plus reporter gene into the genome of a S. glauca through the Agrobacterium-mediated gene transfer method which is the first report in India. Leaf explants co-cultivated with Agrobacterium LBA4404 strains harboring pCAMBIA 1305.1 vector have shown the presence of GUS Plus and HptII gene by PCR analysis as well as GUS assay. The outcome of our research provides fundamental information on efficient gene transformation in S. glauca which will help to enhance future research on the genetic transformation of S. glauca.

Agrobacterium-mediated gene transfer: recent advancements and layered immunity in plants.

Main conclusionPlant responds to Agrobacterium via three-layered immunity that determines its susceptibility or resistance to Agrobacterium infection.Agrobacterium tumefaciens is a soil-borne Gram-negative bacterium that causes crown gall disease in plants. The remarkable feat of interkingdom gene transfer has been extensively utilised in plant biotechnology to transform plant as well as non-host systems. In the past two decades, the molecular mode of the pathogenesis of A. tumefaciens has been extensively studied. Agrobacterium has also been utilised as a premier model to understand the defence response of plants during plant–Agrobacterium interaction. Nonetheless, the threat of Agrobacterium-mediated crown gall disease persists and is associated with a huge loss of plant vigour in agriculture. Understanding the molecular dialogues between these two interkingdom species might provide a cure for crown gall disease. Plants respond to A. tumefaciens by mounting a three-layered immune response, which is manipulated by Agrobacterium via its virulence effector proteins. Comparative studies on plant defence proteins versus the counter-defence of Agrobacterium have shed light on plant susceptibility and tolerance. It is possible to manipulate a plant’s immune system to overcome the crown gall disease and increase its competence via A. tumefaciens-mediated transformation. This review summarises the recent advances in the molecular mode of Agrobacterium pathogenesis as well as the three-layered immune response of plants against Agrobacterium infection.

Development of a New Genetic Transformation System for White and Green Ash Using Embryogenic Cultures

All North American ash (Fraxinus spp.) species are threatened by the emerald ash borer (EAB; Agrilus planipennis), an exotic beetle which has already destroyed millions of ash trees in the U.S. and Canada. Although both chemical insecticides and biological control can be effective, and host resistance appears possible, the speed of the invasion has defied traditional management approaches. One potential, innovative approach to managing this destructive insect is to develop a host tree-induced gene silencing strategy using RNA interference (RNAi) constructs targeting EAB-specific genes. An important requirement for applying RNAi technology is a reliable transformation/regeneration system for the host tree species. We developed an Agrobacterium-mediated gene transfer system for white ash (F. americana) and green ash (F. pennsylvanica) using the embryogenic cultures of these species as target material. Embryogenic suspension cultures of multiple genotypes of both species were plated and inoculated with A. tumefaciens carrying the pFHI-GUSi expression vector, which carries the nptII selectable marker and intron-GUS reporter genes, followed by selection on a semi-solid medium containing geneticin. Putative transgenic events showed expression of the GUS gene at all tested developmental stages from callus to plantlets, and transgene presence in the leaves of regenerated plants was confirmed using PCR. The overall average transformation efficiency achieved was 14.5 transgenic events per gram of tissue. Transgenic somatic seedlings of two white ash and three green ash genotypes were produced and acclimated to greenhouse conditions.

Knockout of Tobacco Homologs of Arabidopsis Multi-Antibiotic Resistance 1 Gene Confers a Limited Resistance to Aminoglycoside Antibiotics.

To explore a possible recessive selective marker for future DNA-free genome editing by direct delivery of a CRISPR/Cas9-single guide RNA (sgRNA) ribonucleoprotein complex, we knocked out homologs of the Arabidopsis Multi-Antibiotic Resistance 1 (MAR1)/RTS3 gene, mutations of which confer aminoglycoside resistance, in tobacco plants by an efficient Agrobacterium-mediated gene transfer. A Cas9 gene was introduced into Nicotiana tabacum and Nicotiana sylvestris together with an sgRNA gene for one of three different target sequences designed to perfectly match sequences in both S- and T-genome copies of N. tabacum MAR1 homologs (NtMAR1hs). All three sgRNAs directed the introduction of InDels into NtMAR1hs, as demonstrated by CAPS and amplicon sequencing analyses, albeit with varying efficiency. Leaves of regenerated transformant shoots were evaluated for aminoglycoside resistance on shoot-induction media containing different aminoglycoside antibiotics. All transformants tested were as sensitive to those antibiotics as non-transformed control plants, regardless of the mutation rates in NtMAR1hs. The NtMAR1hs–knockout seedlings of the T1 generation showed limited aminoglycoside resistance but failed to form shoots when cultured on shoot-induction media containing kanamycin. The results suggest that, like Arabidopsis MAR1, NtMAR1hs have a role in plants’ sensitivity to aminoglycoside antibiotics, and that tobacco has some additional functional homologs.

A potato intragene overexpressing GSL1 confers resistance to Pectobacterium atrosepticum

ABSTRACT An intragene involves the rearrangement of gene configurations based on switching coding sequences and regulatory regions within a species. The overexpression of specific GSL (Gibberellin Stimulated-Like) genes is known to confer enhanced disease resistance. A potato intragenic expression cassette, with the potato GSL1 gene placed under the regulatory control of the light-inducible Lhca3 gene from potato, was designed and constructed. The resulting intragene was transformed using Agrobacterium-mediated gene transfer into potato cultivar Iwa to investigate whether overexpression of the potato GSL1 intragene can confer disease resistance. The transgenic status of the resulting plants was confirmed by PCR. The majority of the transgenic potato lines were determined to overexpress the GSL1 gene at the mRNA level using quantitative RT–PCR analysis. From these results, seven lines were selected for further characterisation and thoroughly evaluated in bioassays for resistance to Pectobacterium atrosepticum which causes blackleg disease in potato. These pathogenicity bioassays demonstrated that high transcriptional overexpression of GSL1 confers high resistance to blackleg disease. This confirms a functional role of the GSL1 gene in plant defence against pathogens and provides an intragenic approach for disease resistance in potatoes.

Development of Transgenic Plants against Biotic Stress through Agrobacterium Mediated Gene Transfer Method

Development of Transgenic Plants against Biotic Stress through Agrobacterium Mediated Gene Transfer Method

Optimization of Agrobacterium-mediated transformation and regeneration for CRISPR/ Cas9 genome editing of commercial tomato cultivars

Tomato (Solanum lycopersicum) is the second most important horticultural crop worldwide that is widely used as a model plant in genetic manipulation of Solanaceae. CRISPR/Cas9 system has been successfully utilized in several studies for genome edition of model tomato cultivars. However, these genome editing systems should be also optimized for commercial tomato cultivar for direct application of genome editing in field conditions. In this study, we have optimized an Agrobacterium-mediated gene transfer and regeneration system for CRISPR/Cas9 genome editing in two commercial tomato cultivars for the first time. The effect of explant type, genotype, pre-transformation time, Agrobacterium concentration, infection time, and different co-culture periods of bacteria were evaluated to optimize the regeneration and transformation parameters. The highest regeneration capacity of 83% was obtained from cotyledons of Crocker incubated in a medium supplemented with BA (3 mg/L) and IAA (0.1 mg/L). The maximum transformation frequency was obtained by using the following parameters: cotyledon explants of commercial Crocker cultivar that were left for 2 days of pre-transformation incubation, infected with Agrobacterium for 10 min at a concentration of OD600 of 0.6 and co-cultivated with Agrobacterium cells for 48 h. CRISPR/Cas9 system was tested with two gRNAs targeting the phytoene desaturase gene. Fully albino and chimeric plants were successfully produced with optimized transformation and culture conditions in up to 71% of all regenerated plants. In the current study, we optimized the implementation of the CRISPR/Cas9 technique in a commercial tomato cultivar and our method will enable breeders to make necessary changes in traits of interest to improve tomato crops for commercial applications.

A Traceable DNA-Replicon Derived Vector to Speed Up Gene Editing in Potato: Interrupting Genes Related to Undesirable Postharvest Tuber Traits as an Example.

In potato (Solanum tuberosum L.), protoplast techniques are limited to a few genotypes; thus, the use of regular regeneration procedures of multicellular explants causes us to face complexities associated to CRISPR/Cas9 gene editing efficiency and final identification of individuals. Geminivirus-based replicons contained in T-DNAs could provide an improvement to these procedures considering their cargo capability. We built a Bean yellow dwarf virus-derived replicon vector, pGEF-U, that expresses all the editing reagents under a multi-guide RNA condition, and the Green Fluorescent Protein (GFP) marker gene. Agrobacterium-mediated gene transfer experiments were carried out on ‘Yagana-INIA’, a relevant local variety with no previous regeneration protocol. Assays showed that pGEF-U had GFP transient expression for up to 10 days post-infiltration when leaf explants were used. A dedicated potato genome analysis tool allowed for the design of guide RNA pairs to induce double cuts of genes associated to enzymatic browning (StPPO1 and 2) and to cold-induced sweetening (StvacINV1 and StBAM1). Monitoring GFP at 7 days post-infiltration, explants led to vector validation as well as to selection for regeneration (34.3% of starting explants). Plant sets were evaluated for the targeted deletion, showing individuals edited for StPPO1 and StBAM1 genes (1 and 4 lines, respectively), although with a transgenic condition. While no targeted deletion was seen in StvacINV1 and StPPO2 plant sets, stable GFP-expressing calli were chosen for analysis; we observed different repair alternatives, ranging from the expected loss of large gene fragments to those showing punctual insertions/deletions at both cut sites or incomplete repairs along the target region. Results validate pGEF-U for gene editing coupled to regular regeneration protocols, and both targeted deletion and single site editings encourage further characterization of the set of plants already generated.

Recovery of phenotypically normal transgenic potato plants is facilitated by regenerating multiple lines from transformation events: field validation using a cry9Aa2 gene conferring insect resistance

ABSTRACT A modified cry9Aa2 gene under the transcriptional control of the CaMV 35S promoter was transferred to four potato cultivars (‘Iwa’, ‘Karaka’, ‘Pacific’ and ‘Red Rascal’) using Agrobacterium-mediated gene transfer. Field plots were established for 170 independently regenerated transgenic lines derived from 113 transformation events. Phenotypic changes such as stunted plants, reduced vigour and/or leaf puckering, were observed in 29% of these lines. Foliage from the remaining 117 lines inhibited larval growth of potato tuber moth (Phthorimaea operculella Zeller) compared with non-transgenic controls. A high correlation was observed between greenhouse- and field-grown foliage for insect resistance using a detached leaf bioassay. Independently regenerated lines recovered from the same transformation event exhibited similar insect resistance. However, these lines derived from the same transformed cell differed markedly in phenotypic appearance and tuber yield. The first shoot regenerated from each transformation event was equivalent to the non-transgenic control for yield traits in only eight transformation events. A further 19 transformation events exhibited agronomic performance equivalent to the non-transgenic control when the second or subsequent regenerated shoots were evaluated. In clonal crops, multiple shoots from each transformation event should be independently assessed to ensure recovery of high-performing transgenic lines.

High-efficiency plastome base editing in rice with TAL cytosine deaminase

High-efficiency plastome base editing in rice with TAL cytosine deaminase

New naturally transgenic plants: 2020 update

Agrobacterium-mediated gene transfer leads to crown gall or hairy roots disease, due to expression of transferred T-DNA genes. Spontaneous plant regeneration from the transformed tissues can produce natural transformants carrying cellular T-DNA (cT-DNA) sequences of agrobacterial origin. In 2019, based on genomic sequencing data, cT-DNA horizontally transferred from Agrobacterium were found in two dozen species of angiosperms. This made it possible to evaluate the spread of this phenomenon, as well as make some generalizations regarding the diversity of horizontally transferred genes. The presented research is a continuation of work in this field. It resulted in the description of new naturally occurring transgenic species Aeschynomene evenia C. Wright, Eperua falcata Aubl., Eucalyptus cloeziana F.Muell., Boswellia sacra Flueck., Kewa caespitosa (Friedrich) Christenh., Pharnaceum exiguum Adamson, Silene noctiflora L., Nyssa sinensis Oliv., Vaccinium corymbosum L., Populus alba L. × Populus glandulosa Moench. The previously identified patterns regarding the frequency of the occurrence of natural transformants and the general properties of the cT-DNAs were confirmed in this study.

Establishment of Glyoxalase I gene transformation and regeneration of cotton (Gossypium hirsutum L.)

Aim: The current study was carried out to develop transgenic cotton plantlets with glyoxalase I (gly I) gene using Agrobacterium-mediated transformation. Methodology: Seeds of cotton were inoculated on MS medium and the explants such as shoot tip (3-5 mm), hypocotyl and leaf were aseptically removed from in vitro plantlets. The pre-cultured and infected explants with Agrobacterium harboring gly I gene and the shoot tip were inoculated on MS media for shoot initiation and subcultured on elongation medium with growth hormones, and antibiotics. Healthy and well-grown shoots were subcultured on medium with indole butyric acid (IBA) (0.3 mgl-1) for root formation and the plantlets were hardened in plastic cups with sterile soil. The putative transgenic plantlets were analyzed histochemically for gus gene and the PCR analysis was performed for gly 1 gene. Results: The transformation efficiency of cotton ranged 48.57 to 64.53 %. The regenerated plantlets showed the presence of gus gene in terms of blue coloration in shoots, whole leaf and leaf segments. The PCR was performed in putative transgenic plant lets with both gus gene as well as gly I gene primers. The PCR results showed the presence of 1031 bp DNA band with gus gene primers and 800 bp DNA band with the gly I gene primers. Interpretation: The current study has proven the reproducible procedure for the Agrobacterium-mediated gene transfer and regeneration of Indian cotton varieties. The PCR results revealed the presence of glyoxalase I gene in the transformants. Key words: Cotton varieties, Glyoxalase I gene, PCR analysis, Regeneration, Transformation