60 research outputs found

    Targeted genome modifications in soybean with CRISPR/Cas9

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    Background: The ability to selectively alter genomic DNA sequences in vivo is a powerful tool for basic and applied research. The CRISPR/Cas9 system precisely mutates DNA sequences in a number of organisms. Here, the CRISPR/Cas9 system is shown to be effective in soybean by knocking-out a green fluorescent protein (GFP) transgene and modifying nine endogenous loci. Results: Targeted DNA mutations were detected in 95% of 88 hairy-root transgenic events analyzed. Bi-allelic mutations were detected in events transformed with eight of the nine targeting vectors. Small deletions were the most common type of mutation produced, although SNPs and short insertions were also observed. Homoeologous genes were successfully targeted singly and together, demonstrating that CRISPR/Cas9 can both selectively, and generally, target members of gene families. Somatic embryo cultures were also modified to enable the production of plants with heritable mutations, with the frequency of DNA modifications increasing with culture time. A novel cloning strategy and vector system based on In-Fusion (R) cloning was developed to simplify the production of CRISPR/Cas9 targeting vectors, which should be applicable for targeting any gene in any organism. Conclusions: The CRISPR/Cas9 is a simple, efficient, and highly specific genome editing tool in soybean. Although some vectors are more efficient than others, it is possible to edit duplicated genes relatively easily. The vectors and methods developed here will be useful for the application of CRISPR/Cas9 to soybean and other plant species

    The Rice Miniature Inverted Repeat Transposable Element mPing Is an Effective Insertional Mutagen in Soybean

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    Insertional mutagenesis of legume genomes such as soybean (Glycine max) should aid in identifying genes responsible for key traits such as nitrogen fixation and seed quality. The relatively low throughput of soybean transformation necessitates the use of a transposon-tagging strategy where a single transformation event will produce many mutations over a number of generations. However, existing transposon-tagging tools being used in legumes are of limited utility because of restricted transposition (Ac/Ds: soybean) or the requirement for tissue culture activation (Tnt1: Medicago truncatula). A recently discovered transposable element from rice (Oryza sativa), mPing, and the genes required for its mobilization, were transferred to soybean to determine if it will be an improvement over the other available transposon-tagging tools. Stable transformation events in soybean were tested for mPing transposition. Analysis of mPing excision at early and late embryo developmental stages revealed increased excision during late development in most transgenic lines, suggesting that transposition is developmentally regulated. Transgenic lines that produced heritable mPing insertions were identified, with the plants from the highest activity line producing at least one new insertion per generation. Analysis of the mPing insertion sites in the soybean genome revealed that features displayed in rice were retained including transposition to unlinked sites and a preference for insertion within 2.5 kb of a gene. Taken together these findings indicate that mPing has the characteristics necessary for an effective transposon-tagging resource

    Switchgrass (\u3ci\u3ePanicum virgatum\u3c/i\u3e L.) polyubiquitin gene (\u3ci\u3ePvUbi1\u3c/i\u3e and \u3ci\u3ePvUbi2\u3c/i\u3e) promoters for use in plant transformation

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    Abstract Background The ubiquitin protein is present in all eukaryotic cells and promoters from ubiquitin genes are good candidates to regulate the constitutive expression of transgenes in plants. Therefore, two switchgrass (Panicum virgatum L.) ubiquitin genes (PvUbi1 and PvUbi2) were cloned and characterized. Reporter constructs were produced containing the isolated 5\u27 upstream regulatory regions of the coding sequences (i.e. PvUbi1 and PvUbi2 promoters) fused to the uidA coding region (GUS) and tested for transient and stable expression in a variety of plant species and tissues. Results PvUbi1 consists of 607 bp containing cis-acting regulatory elements, a 5\u27 untranslated region (UTR) containing a 93 bp non-coding exon and a 1291 bp intron, and a 918 bp open reading frame (ORF) that encodes four tandem, head -to-tail ubiquitin monomer repeats followed by a 191 bp 3\u27 UTR. PvUbi2 consists of 692 bp containing cis-acting regulatory elements, a 5\u27 UTR containing a 97 bp non-coding exon and a 1072 bp intron, a 1146 bp ORF that encodes five tandem ubiquitin monomer repeats and a 183 bp 3\u27 UTR. PvUbi1 and PvUbi2 were expressed in all examined switchgrass tissues as measured by qRT-PCR. Using biolistic bombardment, PvUbi1 and PvUbi2 promoters showed strong expression in switchgrass and rice callus, equaling or surpassing the expression levels of the CaMV 35S, 2x35S, ZmUbi1, and OsAct1 promoters. GUS staining following stable transformation in rice demonstrated that the PvUbi1 and PvUbi2 promoters drove expression in all examined tissues. When stably transformed into tobacco (Nicotiana tabacum), the PvUbi2+3 and PvUbi2+9 promoter fusion variants showed expression in vascular and reproductive tissues. Conclusions The PvUbi1 and PvUbi2 promoters drive expression in switchgrass, rice and tobacco and are strong constitutive promoter candidates that will be useful in genetic transformation of monocots and dicots

    A source of resistance against yellow mosaic disease in soybeans correlates with a novel mutation in a resistance gene

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    Yellow mosaic disease (YMD) is one of the major devastating constraints to soybean production in Pakistan. In the present study, we report the identification of resistant soybean germplasm and a novel mutation linked with disease susceptibility. Diverse soybean germplasm were screened to identify YMD-resistant lines under natural field conditions during 2016-2020. The severity of YMD was recorded based on symptoms and was grouped according to the disease rating scale, which ranges from 0 to 5, and named as highly resistant (HR), moderately resistant (MR), resistant (R), susceptible (S), moderately susceptible (MS), and highly susceptible (HS), respectively. A HR plant named “NBG-SG Soybean” was identified, which showed stable resistance for 5 years (2016-2020) at the experimental field of the National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan, a location that is a hot spot area for virus infection. HS soybean germplasm were also identified as NBG-47 (PI628963), NBG-117 (PI548655), SPS-C1 (PI553045), SPS-C9 (PI639187), and cv. NARC-2021. The YMD adversely affected the yield and a significant difference was found in the potential yield of NBG-SG-soybean (3.46 ± 0.13a t/ha) with HS soybean germplasm NARC-2021 (0.44 ± 0.01c t/ha) and NBG-117 (1.12 ± 0.01d t/ha), respectively. The YMD incidence was also measured each year (2016-2020) and data showed a significant difference in the percent disease incidence in the year 2016 and 2018 and a decrease after 2019 when resistant lines were planted. The resistance in NBG-SG soybean was further confirmed by testing for an already known mutation (SNP at 149th position) for YMD in the Glyma.18G025100 gene of soybean. The susceptible soybean germplasm in the field was found positive for the said mutation. Moreover, an ortholog of the CYR-1 viral resistance gene from black gram was identified in soybean as Glyma.13G194500, which has a novel deletion (28bp/90bp) in the 5`UTR of susceptible germplasm. The characterized soybean lines from this study will assist in starting soybean breeding programs for YMD resistance. This is the first study regarding screening and molecular analysis of soybean germplasm for YMD resistance

    Switchgrass (Panicum virgatum L.) polyubiquitin gene (PvUbi1 and PvUbi2) promoters for use in plant transformation

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    <p>Abstract</p> <p>Background</p> <p>The ubiquitin protein is present in all eukaryotic cells and promoters from ubiquitin genes are good candidates to regulate the constitutive expression of transgenes in plants. Therefore, two switchgrass (<it>Panicum virgatum </it>L.) ubiquitin genes (<it>PvUbi1 </it>and <it>PvUbi2</it>) were cloned and characterized. Reporter constructs were produced containing the isolated 5' upstream regulatory regions of the coding sequences (i.e. <it>PvUbi1 </it>and <it>PvUbi2 </it>promoters) fused to the <it>uidA </it>coding region (<it>GUS</it>) and tested for transient and stable expression in a variety of plant species and tissues.</p> <p>Results</p> <p><it>PvUbi1 </it>consists of 607 bp containing <it>cis</it>-acting regulatory elements, a 5' untranslated region (UTR) containing a 93 bp non-coding exon and a 1291 bp intron, and a 918 bp open reading frame (ORF) that encodes four tandem, head -to-tail ubiquitin monomer repeats followed by a 191 bp 3' UTR. <it>PvUbi2 </it>consists of 692 bp containing <it>cis</it>-acting regulatory elements, a 5' UTR containing a 97 bp non-coding exon and a 1072 bp intron, a 1146 bp ORF that encodes five tandem ubiquitin monomer repeats and a 183 bp 3' UTR. <it>PvUbi1 </it>and <it>PvUbi2 </it>were expressed in all examined switchgrass tissues as measured by qRT-PCR. Using biolistic bombardment, <it>PvUbi1 </it>and <it>PvUbi2 </it>promoters showed strong expression in switchgrass and rice callus, equaling or surpassing the expression levels of the CaMV <it>35S, 2x35S, ZmUbi1</it>, and <it>OsAct1 </it>promoters. GUS staining following stable transformation in rice demonstrated that the <it>PvUbi1 </it>and <it>PvUbi2 </it>promoters drove expression in all examined tissues. When stably transformed into tobacco (<it>Nicotiana tabacum</it>), the <it>PvUbi2+3 </it>and <it>PvUbi2+9 </it>promoter fusion variants showed expression in vascular and reproductive tissues.</p> <p>Conclusions</p> <p>The <it>PvUbi1 </it>and <it>PvUbi2 </it>promoters drive expression in switchgrass, rice and tobacco and are strong constitutive promoter candidates that will be useful in genetic transformation of monocots and dicots.</p
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