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Key message: We extended the applicability of the BY-2 cell line as a model by introducing two new selection systems. Our protocol provides guidelines for optimising Basta selection in other recalcitrant models. Tobacco BY-2 cell line is the most commonly used cytological model in plant research. It is uniform, can be simply treated by chemicals, synchronised and easily transformed. However, only a few selection systems are available that complicate advanced studies using multiple stacked transgenes and extensive gene editing. In our work, we adopted for BY-2 cell line two other selection systems: sulfadiazine and phosphinothricin (PPT, an active ingredient of Basta herbicide). We show that sulfadiazine can be used in a wide range of concentrations. It is suitable for co-transformation and subsequent double selection with kanamycin or hygromycin, which are standardly used for BY-2 transformation. We also have domesticated the sulfadiazine resistance for the user-friendly GoldenBraid cloning system. Compared to sulfadiazine, establishing selection on phosphinothricin was considerably more challenging. It did not work in any concentration of PPT with standardly cultured cells. Since the selection is based on blocking glutamine synthetase and consequent ammonium toxicity and deficiency of assimilated nitrogen, we tried to manipulate nitrogen availability. We found that the PPT selection reliably works only with nitrogen-starved cells with reduced nitrate reserves that are selected on a medium without ammonium nitrate. Both these adjustments prevent the release of large amounts of ammonium, which can toxify the entire culture in the case of standardly cultured cells. Since high nitrogen reserves can be a common feature of in vitro cultures grown on MS media, nitrogen starvation could be a key step in establishing phosphinothricin resistance in other plant models. [ABSTRACT FROM AUTHOR]

The fast spread of bacteria that are resistant to many classes of antibiotics (multidrug resistant) is a global threat to human and animal health with a worrisome scenario ahead. Novel therapeutical strategies are of crucial importance to combat this phenomenon. For this purpose, we investigated the antimicrobial properties of the naturally occurring tripeptide Bialaphos and a dipeptide L-leucyl-L-phosphinoithricin, the synthesis and diastereomers separation of which are herein described. We demonstrate that these compounds are effective on clinical isolates of the human pathogen Klebsiella pneumoniae, causing hospital-acquired and community-acquired infections. The tested isolates were remarkable for their resistance to more than 20 commercial antibiotics of different classes. Based on previous literature data and our experiments consisting of glutamine supplementation, we suggest that both compounds release phosphinothricin—a well-known nanomolar inhibitor of glutamine synthetase—after their penetration in the bacterial cells; and, in this way, exert their antibacterial effect by negatively affecting nitrogen assimilation in this pathogen. [ABSTRACT FROM AUTHOR]

For maize genome-editing and bioengineering, genetic transformation of inbred genotypes is most desired due to the uniformity of genetic background in their progenies. However, most maize inbred lines are recalcitrant to tissue culture and transformation. A public, transformable maize inbred B104 has been widely used for genome editing in recent years. This is primarily due to its high degree of genetic similarity shared with B73, an inbred of the reference genome and parent of many breeding populations. Conventional B104 maize transformation protocol requires 16–22 weeks to produce rooted transgenic plants with an average of 4% transformation frequency (number of T0 plants per 100 infected embryos). In this Method paper, we describe an advanced B104 transformation protocol that requires only 7–10 weeks to generate transgenic plants with an average of 6.4% transformation frequency. Over 66% of transgenic plants carried CRISPR/Cas9-induced indel mutations on the target gene, demonstrating that this protocol can be used for genome editing applications. Following the detailed and stepwise procedure described here, this quick and simplified method using the Agrobacterium ternary vector system consisting of a T-DNA binary vector and a compatible helper plasmid can be readily transferable to interested researchers. [ABSTRACT FROM AUTHOR]

For maize genome-editing and bioengineering, genetic transformation of inbred genotypes is most desired due to the uniformity of genetic background in their progenies. However, most maize inbred lines are recalcitrant to tissue culture and transformation. A public, transformable maize inbred B104 has been widely used for genome editing in recent years. This is primarily due to its high degree of genetic similarity shared with B73, an inbred of the reference genome and parent of many breeding populations. Conventional B104 maize transformation protocol requires 16–22 weeks to produce rooted transgenic plants with an average of 4% transformation frequency (number of T0 plants per 100 infected embryos). In this Method paper, we describe an advanced B104 transformation protocol that requires only 7–10 weeks to generate transgenic plants with an average of 6.4% transformation frequency. Over 66% of transgenic plants carried CRISPR/Cas9-induced indel mutations on the target gene, demonstrating that this protocol can be used for genome editing applications. Following the detailed and stepwise procedure described here, this quick and simplified method using the Agrobacterium ternary vector system consisting of a T-DNA binary vector and a compatible helper plasmid can be readily transferable to interested researchers.

A novel magnetic metal‐organic framework composite was prepared by a self‐assembly approach. The material properties were characterized by Fourier‐transform infrared spectroscopy, vibrating sample magnetometry, thermogravimetry and differential thermogravimetric analysis, and X‐photoelectron spectroscopy. Then, the as‐prepared material was used as an adsorbent and indicated great enrichment ability toward glyphosate, glufosinate, bialaphos, and their main metabolites aminomethylphosphonic acid and 3‐methylphosphinicopropionic acid. Based on this, an efficient magnetic solid‐phase extraction method combined with ultra high performance liquid chromatography with high‐resolution mass spectrometry for the pretreatment and determination of five target compounds in environmental waters was established. Parameters that could impact on the adsorption performance had been studied in detail. The proposed method was successfully applied for the simultaneous determination of glyphosate, glufosinate, bialaphos, and their main metabolites aminomethylphosphonic acid and 3‐methylphosphinicopropionic acid in environmental water with recoveries in range of 86.2–104.6% with relative standard deviations less than 10%. Desired linearity was achieved varying from 1 to 100 μg/L for five target analytes, respectively. The limits of detection were between 0.01 and 0.03 μg/L. [ABSTRACT FROM AUTHOR]

An in vitro plant generation and genetic transformation protocol was established in sesame ( Sesamum indicum L. cv Rama) through biolistic particle gun bombardment. 5-day-old apical, meristematic tissues of in vitro-germinating seedlings were used as explants. 10-15 Multiple shoots were generated from each explant using Murashige and Skoog basal medium containing 18.0 µM benzylamino purine and 5.37 µM naphthalene acetic acid. Four independent sets of transformation were carried out and each set consisted of three independent experiments each comprising three replications with 30 explants per replication. A synthetically designed bialaphos resistance gene ( bar) was used for transformation. The positive transformants containing the bar gene were selected in growth medium containing 2.5 mg/L bialaphos. Green shoots recovered from bombarded explants were subjected to root development on Murashige and Skoog basal medium containing 5.37 µM naphthalene acetic acid. The rooted shoots were established in soil and grown to maturity in greenhouse. Polymerase chain reaction (PCR), Southern and reverse-transcription PCR, real-time quantitative PCR, western blot and enzymatic assay of four putative transformants from independent sets provided evidence for full-length gene integration as well as high level expression of the transgene. Analysis of the T plants revealed a stable inheritance of the transgene through the progenies. This is the first report of biolistic mediated stable transformation of sesame and should pave the way for future genetic engineering strategies to be employed for improvement of this very important oil-seed crop. [ABSTRACT FROM AUTHOR]

A modular, selection-based method was developed for site-specific integration of transgenes into a genomic locus to create multigene stacks. High-frequency gene targeting was obtained using zinc finger nuclease (ZFN)-mediated double-strand break (DSB) formation at a pre-defined target genomic location using a unique intron directly downstream of a promoter driving a selectable marker gene to facilitate homology between target and donor sequences. In this system, only insertion into the target locus leads to a functional selectable marker, and regeneration from random insertions of the promoterless donor construct are reduced on selection media. A new stack of transgenes can potentially be loaded with each successive cycle of gene targeting by exchanging the selectable marker gene using the intron homology. This system was tested in maize using the pat selectable marker gene, whereby up to 30% of the plants regenerated on Bialaphos-containing medium were observed to have the donor construct integrated into the target locus. Unlike previous gene targeting methods that utilize defective or partial genes for selecting targeted events, the present method exchanges fully functional genes with every cycle of targeting, thereby allowing the recycling of selectable marker genes, hypothetically for multiple generations of gene targeting. [ABSTRACT FROM AUTHOR]

The goal of this work was to establish a transformation pipeline for upland Curinga rice ( Oryza sativa L. ssp. japonica) with bar gene selection employing bialaphos and phosphinothricin as selection agents. The following genes of interest: AtNCED3, Lsi1, GLU2, LEW2, PLD- alpha, DA1, TOR, AVP1, and Rubisco were cloned into the binary vector p7i2x-Ubi and were transferred into Agrobacterium strain EHA 105. Embryogenic calli derived from the mature embryos were transformed, and transgenic cells and shoots were selected on the medium supplemented with bialaphos or phosphinothricin (PPT) using a stepwise selection scheme. Molecular analyses were established using polymerase chain reaction and Southern blot for the bar gene and the NOS terminator. Overall, 273 putative transgenic plants were analyzed by Southern blot with 134 events identified. In total, 77 events had a single copy of the transgene integrated in the plant genome while 29 events had two copies. We tested backbone integration in 101 transgenic plants from all constructs and found 60 transgenic plants having no additional sequence integrated in the plant genome. The bar gene activity was evaluated by the chlorophenol red test and the leaf painting test using phosphinothricin with several transgenic plants. The majority of T0 plants carrying the single copy of transgene produced T1 seeds in the screen house. [ABSTRACT FROM AUTHOR]

An in vitro plant regeneration and genetic transformation protocol was established in jute ( Corchorus capsularis L. var JRC321). One-day-old apical, meristematic tissues of germinating seedlings were used as explants. Multiple shoots were regenerated from each explant using Murashige and Skoog basal medium containing 1.78 µM benzylamino purine and 4.92 µM indole-3-butyric acid. Transformation was carried out in three independent sets (each set comprising of three independent experiments each comprising three replications with 35 explants per replication) using the bialaphos resistance gene ( bar), synthetically designed for high level plant expression. The positive transformants containing the bar gene were selected in growth medium containing 2.5 mg/l bialaphos. Polymerase chain reaction (PCR), Southern and northern blots, real-time quantitative PCR, western blot and enzymatic assay of five putative transformants from three independent sets provided evidence for full-length gene integration into the genomic DNA of transformed jute, as well as high level expression of the transgene. Analysis of the T plants revealed a stable inheritance of the transgene through the progenies. The data presented in this report showed considerable advancement in jute transformation and should improve future genetic engineering strategies to be employed for improvement of this very important fibre crop. [ABSTRACT FROM AUTHOR]

Pleurotus ostreatus was transformed using the nourseothricin-resistant gene for the first time. The transformation efficiency was 1.3 ± 0.6 transformants/μg plasmid DNA. In addition, the transformation efficiency of the bialaphos-resistant gene was increased to 26.7 ± 11.5 transformants/μg plasmid DNA. [ABSTRACT FROM AUTHOR]

Highlights: [•] Encoding of the novel promoter region of Aspergillus niger bglII was performed. [•] A high efficacy promoter d3 was constructed. [•] The transformant d3 was free from glucose repression. [•] The promoter of d3 transformant produced heterologous/homologous proteins in fungi. [ABSTRACT FROM AUTHOR]

A stable Agrobacterium-mediated transformation system was established using bialaphos as the selective agent in soybeans [Glycine max (L.) Merr.]. The cotyledonary node explants of the soybean cultivar 'NY-1001' were inoculated with the Agrobacterium tumefaciens strain EHA105, harboring the vector pCAMBIA3301 containing the gus gene as the reporter gene and the bar gene conferring bialaphos resistance. The highest frequency of GUS transient expression (92%) was obtained after inoculation and 4-day co-cultivation with A. tumefaciens strain EHA105. Efficient GUS expression was observed in regenerated shoots from explants after 4-day co-cultivation combined with culturing on shoot induction medium (SIM) without bialaphos for 7 days followed by 4 mg.L-1 bialaphos for 2 weeks. Bialaphos (4 mg.L-1 in SIM; 2 mg.L-1 in shoot elongation medium (SEM)) effectively selected the transformants. The putative transformants and escapes could be exactly distinguished by using a half-leaf GUS assay method to detect GUS expression in the elongated resistant shoots, which resulted in the shortening of culture period for the early detection of transformed shoots. The transformation efficiency of this system was 1.06%. The transgenic plants were verified by polymerase chain reaction (PCR), Southern blotting, and herbicide-resistant responses. All four T0 transgenic plants were fertile and transmitted the phenotypes of both gus and bar in a 3:1 ratio to their progeny. These results indicate that the established system is suitable for further breeding of herbicide-resistant transgenic cultivars, as well as for functional genomics studies of soybeans. [ABSTRACT FROM AUTHOR]

Resistance to the non-selective herbicide dl-phosphinothricin ( PPT) was introduced into commercial Lotus corniculatus cv. Bokor by co-cultivation of cotyledons with Agrobacterium tumefaciens AGL1 harbouring the binary vector pDM805 which contains the bialaphos resistance gene ( bar) from Streptomyces hygroscopicus encoding phosphinothricin acetyltransferase ( PAT) and the uidA gene encoding β-glucuronidase. The half-cotyledon explants were precultured on regeneration Murashige and Skoog's (MS) medium supplemented with 6-benzyladenine (BA) and 1-naphthaleneacetic acid (NAA) at 0.5 mg L−1 each, 3 days prior to infection. Upon co-cultivation, the explants were cultured on PPT-free regeneration medium for 10 days, and then subcultured on regeneration/selection media with increasing PPT concentrations (5-7 mg L−1) for about 18 weeks. Out of 480 initially co-cultivated explants, 272 regenerated shoots survived the entire PPT selection procedure. Resistant shoots were grown further, multiplied by tillering that was additionally promoted by PPT and rooted on hormone-free MS medium containing 5 mg L−1 PPT. Established shoot cultures, continuously maintained on the same medium, have preserved PPT resistance up to now (more than 2 years). Transformed plants assessed in vitro and in a greenhouse were tolerant to the herbicide PPT at 300 mg L−1 equivalent to more than twofold the recommended field dosage for weed eradication. Applied PPT treatment did not affect the activities of glutamine synthetase (GS; EC 6.3.1.2) and NADH-dependent glutamate dehydrogenase (NADH-GDH; EC 1.4.1.2) in transformed plants. However, PPT did increase the mobility of glutamine synthetase isoforms GS1 and GS2 as well as the inhibition of an additional high mobility GS (hmGS) activity. In untransformed plants, PPT treatment reduced total GS activity by 4.4-fold while contrary the activity of NADH-GDH was increased by ninefold. All transformed herbicide-resistant plants were phenotypically normal and exhibited genomic stability, as were the untransformed plants analysed by flow cytometry. Under greenhouse conditions, they grew to maturity, flowered and set seeds. Stable integration and expression of the bar gene in T0 and T1 plants were confirmed by Southern and Western blot analysis, while integration of the reporter uidA gene did not occur. The bar gene was inherited in a Mendelian fashion by the progeny, as detected by PPT resistance. The production of PPT-resistant plants may have significant practical applications in weed control in fields of L. corniculatus. [ABSTRACT FROM AUTHOR]

This dialogue was held between the Guest Editors of the Special Issue on "Plant Transgenesis" of the Int. J. Dev. Biol. and Marc De Block. He was one of the first scientists worldwide to obtain transgenic plants transformed with the chimeric selectable marker genes encoding neomycin phosphotransferase and bialaphos that confer resistance against the antibiotic kanamycin and the herbicide Basta®/glufosinate, respectively at the Department of Genetics of Ghent University and, later on, at the spin-off company. Plant Genetic Systems. Today, these two genes are still the most frequently utilized markers in transgene technology. Marc De Block chose to work on the improvement of crops in an industrial environment to help realize the production of superior seeds or products. He was part of the team that developed the male sterility/restorer system in canola (Brassica napus var. napus) that led to the first hybrid lines to be commercialized as successful products of transgene technology. In more than 30 years of research, he developed transformation procedures for numerous crops, designed histochemical, biochemical and physiological assays to monitor plant performance, and made original and innovative contributions to plant biology. Presently, he considers transgenic research part of the toolbox for plant improvement and essential for basic plant research. [ABSTRACT FROM AUTHOR]

A major challenge for efficient transgene expression in Dunaliella salina is to find strong endogenous promoters to drive the transgene expression. In the present study, a novel glyceraldehyde-3-phosphate dehydrogenase ( GAPDH) promoter was cloned and used to drive expressions of the bialaphos resistance ( bar) gene and of the N-terminal fragment of human canstatin (Can-N). The results showed that the bar gene was transcribed by the GAPDH promoter and integrated into the genome of the transformants of D. salina. Furthermore, the PCR identification, Southern and western blots indicated that Can-N was expressed in transgenic D. salina, demonstrating that the promoter of the D. salina GAPDH gene is suitable for driving expression of heterologous genes in transgenic D. salina. [ABSTRACT FROM AUTHOR]

Abstract: We developed a simple and rapid method for the simultaneous determination of phosphorus-containing amino acid herbicides (glyphosate, glufosinate, bialaphos) and their major metabolites, aminomethylphosphonic acid (AMPA) and 3-methylphosphinicopropionic acid (MPPA), in human serum. Serum samples were filtrated through an ultrafiltration membrane to remove proteins. The filtrate was then washed with chloroform, and injected into a liquid chromatography–tandem mass spectrometry (LC–MS/MS) system. Chromatographic separation was achieved on a hydrophilic interaction chromatography (HILIC) column. Determination of the target herbicides and metabolites was successfully carried out without derivatization or solid phase extraction (SPE) cartridge clean-up. The recoveries of these compounds, added to human serum at 0.2μg/mL, ranged from 94% to 108%, and the relative standard deviations (RSDs) were within 5.9%. The limits of detection (LODs) were 0.01μg/mL for MPPA, 0.02μg/mL for AMPA, 0.03μg/mL for both glyphosate and glufosinate, and 0.07μg/mL for bialaphos, respectively. [Copyright &y& Elsevier]

Natural products containing carbon-phosphorus bonds (phosphonic and phosphinic acids) have found widespread use in medicine and agriculture. Recent years have seen a renewed interest in the biochemistry and biology of these compounds with the cloning of the biosynthetic gene clusters for several family members. This review discusses the commonalities and differences in the molecular logic that lie behind the biosynthesis of these compounds. The current knowledge regarding the metabolic pathways and enzymes involved in the production of a number of natural products, including the approved antibiotic fosfomycin, the widely used herbicide phosphinothricin (PT), and the clinical candidate for treatment of malaria FR-900098, is presented. Many of the enzymes involved in the biosynthesis of these compounds catalyze chemically and biologically unprecedented transformations, and a wealth of new biochemistry has been revealed through their study. These investigations have also suggested new strategies for natural product discovery. [ABSTRACT FROM AUTHOR]

Abstract: The tremendous increase in crop yields associated with the ‘green’ revolution has been possible in part by the discovery and utilization of chemicals for pest control. However, concerns over the potential impact of pesticides on human health and the environment has led to the introduction of new pesticide registration procedures, such as the Food Quality Protection Act in the United States. These new regulations have reduced the number of synthetic pesticides available in agriculture. Therefore, the current paradigm of relying almost exclusively on chemicals for pest control may need to be reconsidered. New pesticides, including natural product-based pesticides are being discovered and developed to replace the compounds lost due to the new registration requirements. This review covers the historical use of natural products in agricultural practices, the impact of natural products on the development of new pesticides, and the future prospects for natural products-based pest management. [Copyright &y& Elsevier]

The article presents a s study which identifies a novel bacterial Phosphinothricin (PPT) N-acetyltransferase, methione sulfone N-acetylransferase (MAT) through the isolation of the PPT-gene from a soil bacterium Nocardia sp. It was found that MAT has the ability to detoxify the herbicide PPT. In addition, MAT's chloroplast expression can lead to a higher herbicide resistance than expression in the cytosol. It also shows that MAT can be used a selectable marker in plants' transformation.

Protocorms or protocorm-like bodies (PLBs) of three orchid genera, Brassia, Cattleya, and Doritaenopsis, were genetically transformed via microprojectile bombardment using the bar gene from Streptomyces hygroscopicus. Selection for transformed cells was accomplished using bialaphos. PLBs that proliferated on selection medium containing 1 mg/l bialaphos were minced and transferred to selection medium containing 3 mg/l of the herbicide. This selection was repeated twice at 2-month intervals. Putatively transformed plantlets were regenerated in the absence of bialaphos for Doritaenopsis, or on regeneration medium containing 3 mg/l bialaphos for Brassia and Cattleya. Presence of the bar gene in the transformed plants was confirmed by polymerase chain reaction and Southern blot analysis. Transcription of bar was assessed by northern blot analysis. Plantlets of all three genera exhibited functional expression of bar as determined by assaying for resistance to bialaphos applied directly to leaves. [ABSTRACT FROM AUTHOR]

We have isolated a cDNA clone (pSR132) representing a mRNA which accumulates in senescing carnation flower petals in response to ethylene. In vitro translation of RNA selected by hybridization with pSR132 indicated the mRNA encoded a polypeptide of approximately 36 kDa. This was confirmed by DNA sequence analysis, which predicted a peptide composed of 318 amino acids with a calculated molecular weight of 34.1 kDa. Comparison of the predicted peptide sequence of pSR132 with other proteins compiled in the NBRF data base revealed significant homology with carboxyphosphonoenolpyruvate mutase and phosphoenolpyruvate mutase from Streptomyces hygroscopicus and Tetrahymena pyriformis, respectively. These enzymes are involved in the formation of C-P bonds in the biosynthesis of phosphonates. C-P bonds are found in a wide range of organisms, but their presence or formation in higher plants has not been investigated. [ABSTRACT FROM AUTHOR]

We have obtained transgenic lily ( Lilium longiflorum) plants after microprojectile bombardment, using the Biolistics PDS 1000/He system, of morphogenic calli derived from bulblet scales, followed by bialaphos selection. Parameters which gave the highest transient uidA expression were used: a bombardment pressure of 1100 psi, a target distance of 6 cm and a 48-h preculture on medium with 3% sucrose. A total of 1800 morphogenic calli were co-bombarded with plasmids containing either the uidA reporter or PAT selectable marker genes. After bombardment, the calli were exposed to 2 mg/l bialaphos. Only 72 of the shoot-forming calli (4%) survived. The 72 shoot clusters produced 342 shoots on elongation medium containing 0.5 mg/l bialaphos. Only 55 plantlets survived subsequent exposure to 2.0 mg/l bialaphos. PCR analysis indicated that 19 of these plantlets contained the PAT transgene. Southern analysis of 3 of the plants indicated that all contained the PAT gene. [ABSTRACT FROM AUTHOR]

Hairy roots of snapdragon ( Antirrhinum ma-jus L.: Scrophulariaceae) induced by a wild-type strain of Agrobacterium rhizogenes were cultured on media containing various concentrations of a phosphinothricin-based herbicide, bialaphos, or plant growth regulators (PGRs). Adventitious shoot regeneration from hairy roots was observed with a low frequency (10%) on half-strength Murashige and Skoog medium. Addition of α-naphthalene-acetic acid in combination with 6-benzylaminopurine, thidiazuron, or zeatin to the medium had no effect on shoot regeneration from hairy roots. Although bialaphos at 0.9 mg l–1 or more was toxic to hairy roots, it significantly increased the shoot regeneration frequency up to 56% at 0.5 mg l–1. In contrast, non-transformed roots and leaves regenerated no shoots on media with or without bialaphos. Regenerated shoots detached from host roots readily developed roots on gellan-gum-solidified medium. Regenerated plants were successfully transferred to the greenhouse, but did not produce seed. [ABSTRACT FROM AUTHOR]

Callus was initiated from in vitro-grown plants of Gladiolus cultivars ‘Jenny Lee’ and ‘Florida Flame.’ The age of callus used for regeneration of plants was either 9 mo. old or 8 yr old from ‘Jenny Lee,’ and 4 mo. old from ‘Florida Flame.’ Regeneration medium consisted of Murashige and Skoog’s basal salts medium supplemented with 2.0 mg/l (9.3 µ M) kinetin. This medium was supplemented with various concentrations of either bialaphos (Meiji Seika, Tokyo, Japan) or phosphinothricin (Hoechst-Roussell, Frankfurt, Germany). Bialaphos was more effective than phosphinothricin at stimulating plant regeneration. Plants regenerated from 8-yr-old callus of ‘Jenny Lee’ only when the regeneration medium was supplemented with 0.10 mg/l bialaphos. A bialaphos concentration of 0.01 mg/l stimulated regeneration from 9-mo.-old callus of cultivar ‘Jenny Lee’ and 4-mo.-old callus of ‘Florida Flame.’ [ABSTRACT FROM AUTHOR]

Using microprojectile bombardment of maize suspension cultures and bialaphos selection, transformed embryogenic calli have been recovered in numerous independent experiments. Fertile transgenic plants have been regenerated from several transformed callus lines. Stable inheritance and expression of bar and functional activity of the enzyme phosphinothricin acetyl transferase were observed in three subsequent generations of transformed plants. Evidence to date indicates that the transformation process and the presence of the foreign gene per se do not detrimentally influence either plant vigor or fertility. This represents a practical method for introducing foreign genes into maize, which may be applicable to other monocot species. [ABSTRACT FROM AUTHOR]

Conidia of Neurospora crassa are sensitive to the herbicide bialaphos at concentrations of 160 mg/1 in Westergaard's or Fries' minimal media. Plasmid pJA4 was constructed by inserting a truncated bar gene from Streptomyces hygroscopicus fused to the his-3 promoter from N. crassa into pUC19. The bar gene in plasmid pJA4 confers resistance to bialaphos when transformants are selected on a medium containing bialaphos. The bar gene can be used as an additional dominant selectable marker for transformation of fungi. [ABSTRACT FROM AUTHOR]

Stable transformed Black Mexican Sweet (BMS) maize callus was recovered from suspension culture cells bombarded with plasmid DNA that conferred resistance to the herbicide bialaphos. Suspension culture cells were bombarded with a mixture of two plasmids. One plasmid contained a selectable marker gene, bar, which encoded phosphinothricin acetyl transferase (PAT), and the other plasmid encoded a screenable marker for β-glucuronidase (GUS). Bombarded cells were selected on medium containing the herbicide bialaphos, which is cleaved in plant cells to yield phosphinothricin (PPT), an inhibitor of glutamine synthetase. The bialaphos-resistant callus contained the bar gene and expressed PAT as assayed by PPT inactivation. Transformants that expressed high levels of PAT grew more rapidly on increasing concentrations of bialaphos than transformants expressing low levels of PAT. Fifty percent of the bialaphos-resistant transformants tested (8 of 16) expressed the nonselected gene encoding GUS. [ABSTRACT FROM AUTHOR]