Development of a Transformable Fast-Flowering Mini-Maize as a Tool for Maize Gene Editing.

Maize ( ssp. ) is a popular genetic model due to its ease of crossing, well-established toolkits, and its status as a major global food crop. Recent technology developments for precise manipulation of the genome are further impacting both basic biological research and biotechnological application in agriculture.

Sequence of the supernumerary B chromosome of maize provides insight into its drive mechanism and evolution.

B chromosomes are enigmatic elements in thousands of plant and animal genomes that persist in populations despite being nonessential. They circumvent the laws of Mendelian inheritance but the molecular mechanisms underlying this behavior remain unknown. Here we present the sequence, annotation, and analysis of the maize B chromosome providing insight into its drive mechanism.

Biolistic DNA Delivery in Maize Immature Embryos.

One of the key factors for ensuring a successful genetic transformation is to effectively introduce genetic materials, such as plasmid DNA, into plant cells. A biolistic gun is one of the two best established and most popular tools for delivery of DNA into maize cells. It is the method that generated the first fertile transgenic maize plant.

Agrobacterium-Mediated Immature Embryo Transformation of Recalcitrant Maize Inbred Lines Using Morphogenic Genes.

Demonstrated here is a detailed protocol for Agrobacterium-mediated genetic transformation of maize inbred lines using morphogenic genes Baby boom (Bbm) and Wuschel2 (Wus2). Bbm is regulated by the maize phospholipid transferase gene (Pltp) promoter, and Wus2 is under the control of a maize auxin-inducible (Axig1) promoter. An Agrobacterium strain carrying these morphogenic genes on transfer DNA (T-DNA) and extra copies of Agrobacterium virulence (vir) genes are used to infect maize immature embryo explants.

CRISPR/Cas9-mediated targeted T-DNA integration in rice.

Combining with a CRISPR/Cas9 system, Agrobacterium-mediated transformation can lead to precise targeted T-DNA integration in the rice genome. Agrobacterium-mediated T-DNA integration into the plant genomes is random, which often causes variable transgene expression and insertional mutagenesis. Because T-DNA preferentially integrates into double-strand DNA breaks, we adapted a CRISPR/Cas9 system to demonstrate that targeted T-DNA integration can be achieved in the rice genome.