More Like this

1. IMAGE: INTEGRATE-Mediated Agrobacterium Genome Engineering

   https://doi.org/10.3389/fmicb.2025.1676008  

   Aliu, Ephraim; Chen, Liang-Chun; Lee, Keunsub; Wang, Kan (November 2025, Frontiers in Microbiology)

   The ability to precisely engineerAgrobacteriumstrains is crucial for advancing their utility in plant biotechnology. We recently implemented the CRISPR RNA-guided transposase system, INTEGRATE, as an efficient tool for genetic modification inAgrobacterium. Despite its promise, the practical application of INTEGRATE inAgrobacteriumstrain engineering remains underexplored. Here, we present a standardized and optimized workflow that enables researchers to harness INTEGRATE for targeted genome modifications. By addressing common challenges, such as crRNA design, transformation efficiency, and vector eviction, this protocol expands the genetic toolkit available forAgrobacterium, facilitating both functional genomics and strain development for plant transformation. As a demonstration, we domesticatedAgrobacterium rhizogenesK599 strain by deleting the 15-kb T-DNA region from its root-inducing plasmid pRi2659 and inactivating a thymidylate synthase gene to render the strain auxotrophic for thymidine. The protocol provides detailed guidance for each step, including target site selection, crRNA spacer cloning,Agrobacteriumtransformation, screening for targeted insertion and Cre/loxP-mediated deletion, and vector removal. This resource will empower new users to perform efficient and reproducible genome engineering inAgrobacteriumusing the INTEGRATE system, paving the way for broader adoption and innovation in plant biotechnology. 

   more » « less
2. Establishing Reagent Testing Platforms for Functional Analyses in Sunflower

   https://doi.org/10.3390/plants15010089  

   Nasti, Ryan A; Kenderski, Cathy S; Chanchani, Aryaa; Sharma, Ambika; Blackman, Benjamin K (January 2026, Plants)

   Recent advancements in molecular tools for plant genetic engineering, particularly CRISPR-based technologies, have created new opportunities for targeted genome editing. However, applying these tools remains challenging in crop species such as sunflower (Helianthus annuus) that lack established and effective transformation pipelines, including transient reagent delivery methods for functional screening and validation of genetic engineering tools. To address this gap, three major reagent delivery platforms, namely protoplast transfection, leaf infiltration, and Agrobacterium-mediated tissue co-culture, were systematically adapted and assessed for use in sunflower seedlings. While each method enabled successful reagent delivery, they differed in their levels of scalability and efficiency. With these platforms, delivery by different Agrobacterium strains and the effectiveness of various reporter gene expression cassettes were compared to define the most experimentally suitable components for different applications in sunflowers. Together, these results establish a foundational toolkit for transient functional testing in sunflower and pave the way for more sophisticated genetic engineering approaches in this agriculturally important oilseed, confectionary seed, and horticultural crop. 

   more » « less
3. Enhancing Maize Transformation and Targeted Mutagenesis through the Assistance of Non-Integrating Wus2 Vector

   https://doi.org/10.3390/plants12152799  

   Kang, Minjeong; Lee, Keunsub; Ji, Qing; Grosic, Sehiza; Wang, Kan (August 2023, Plants)

   Efficient genetic transformation is a prerequisite for rapid gene functional analyses and crop trait improvements. We recently demonstrated that new T-DNA binary vectors with NptII/G418 selection and a compatible helper plasmid can efficiently transform maize inbred B104 using our rapid Agrobacterium-mediated transformation method. In this work, we implemented the non-integrating Wuschel2 (Wus2) T-DNA vector method for Agrobacterium-mediated B104 transformation and tested its potential for recalcitrant inbred B73 transformation and gene editing. The non-integrating Wus2 (NIW) T-DNA vector-assisted transformation method uses two Agrobacterium strains: one carrying a gene-of-interest (GOI) construct and the other providing an NIW construct. To monitor Wus2 co-integration into the maize genome, we combined the maize Wus2 expression cassette driven by a strong constitutive promoter with a new visible marker RUBY, which produces the purple pigment betalain. As a GOI construct, we used a previously tested CRISPR-Cas9 construct pKL2359 for Glossy2 gene mutagenesis. When both GOI and NIW constructs were delivered by LBA4404Thy- strain, B104 transformation frequency was significantly enhanced by about two-fold (10% vs. 18.8%). Importantly, we were able to transform a recalcitrant inbred B73 using the NIW-assisted transformation method and obtained three transgene-free edited plants by omitting the selection agent G418. These results suggest that NIW-assisted transformation can improve maize B104 transformation frequency and provide a novel option for CRISPR technology for transgene-free genome editing. 

   more » « less
4. History and current status of embryogenic culture‐based tissue culture, transformation and gene editing of maize ( Zea mays L.)

   https://doi.org/10.1002/tpg2.20451  

   McFarland, Frank_L; Kaeppler, Heidi_F (April 2024, The Plant Genome)

   Abstract The production of embryogenic callus and somatic embryos is integral to the genetic improvement of crops via genetic transformation and gene editing. Regenerable embryogenic cultures also form the backbone of many micro‐propagation processes for crop species. In many species, including maize, the ability to produce embryogenic cultures is highly genotype dependent. While some modern transformation and genome editing methods reduce genotype dependence, these efforts ultimately fall short of producing truly genotype‐independent tissue culture methods. Recalcitrant genotypes are still identified in these genotype‐flexible processes, and their presence is magnified by the stark contrast with more amenable lines, which may respond more efficiently by orders of magnitude. This review aims to describe the history of research into somatic embryogenesis, embryogenic tissue cultures, and plant transformation, with particular attention paid to maize. Contemporary research into genotype‐flexible morphogenic gene‐based transformation and genome engineering is also covered in this review. The rapid evolution of plant biotechnology from nascent technologies in the latter half of the 20th century to well‐established, work‐horse production processes has, and will continue to, fundamentally changed agriculture and plant genetics research. 

   more » « less
5. Rhizosphere Microbiomes in a Historical Maize-Soybean Rotation System Respond to Host Species and Nitrogen Fertilization at the Genus and Subgenus Levels

   https://doi.org/10.1128/AEM.03132-20  

   Meier, Michael A.; Lopez-Guerrero, Martha G.; Guo, Ming; Schmer, Marty R.; Herr, Joshua R.; Schnable, James C.; Alfano, James R.; Yang, Jinliang (May 2021, Applied and Environmental Microbiology)

   Liu, Shuang-Jiang (Ed.)

   ABSTRACT Root-associated microbes are key players in plant health, disease resistance, and nitrogen (N) use efficiency. It remains largely unclear how the interplay of biological and environmental factors affects rhizobiome dynamics in agricultural systems. In this study, we quantified the composition of rhizosphere and bulk soil microbial communities associated with maize ( Zea mays L.) and soybean ( Glycine max L.) in a long-term crop rotation study under conventional fertilization and low-N regimes. Over two growing seasons, we evaluated the effects of environmental conditions and several treatment factors on the abundance of rhizosphere- and soil-colonizing microbial taxa. Time of sampling, host plant species, and N fertilization had major effects on microbiomes, while no effect of crop rotation was observed. Using variance partitioning as well as 16S sequence information, we further defined a set of 82 microbial genera and functional taxonomic groups at the subgenus level that show distinct responses to treatment factors. We identified taxa that are highly specific to either maize or soybean rhizospheres, as well as taxa that are sensitive to N fertilization in plant rhizospheres and bulk soil. This study provides insights to harness the full potential of soil microbes in maize and soybean agricultural systems through plant breeding and field management. IMPORTANCE Plant roots are colonized by large numbers of microbes, some of which may help the plant acquire nutrients and fight diseases. Our study contributes to a better understanding of root-colonizing microbes in the widespread and economically important maize-soybean crop rotation system. The long-term goal of this research is to optimize crop plant varieties and field management to create the best possible conditions for beneficial plant-microbe interactions to occur. These beneficial microbes may be harnessed to sustainably reduce dependency on pesticides and industrial fertilizer. We identify groups of microbes specific to the maize or to the soybean host and microbes that are sensitive to nitrogen fertilization. These microbes represent candidates that may be influenced through plant breeding or field management, and future research will be directed toward elucidating their roles in plant health and nitrogen usage. 

   more » « less