Genome Editing of Rice by CRISPR-Cas: End-to-End Pipeline for Crop Improvement.

CRISPR-Cas resonates a revolutionary genome editing technology applicable through a horizon spreading across microbial organism to higher plant and animal. This technology can be harnessed with ease to understand the basic genetics of a living system by altering sequence of individual genes and characterizing their functions. The precision of this technology is unparallel. It allows very precise and targeted base pair level edits in the genome. Here, in the current chapter, we have provided end-to-end process outline on how to generate genome edited plants in crops like rice to evaluate for agronomic traits associated with yield, disease resistance and abiotic stress tolerance, etc. Genome editing process includes designing of gene editing strategy, vector construction, plant transformation, molecular screening, and phenotyping under control environment conditions. Furthermore, its application for development of commercial crop product may require additional processes, including field trials in the target geography for evaluation of product efficacy. Evaluation of genome edited lines in controlled greenhouse/net house or open field condition requires few generations for outcrossing with wild-type parent to eliminate and/or reduce any potential pleiotropic effect in the edited genome which may arise during the process. The genome edited plant selected for advancement shall harbor the genome with only the intended changes, which can be analyzed by various molecular techniques, advanced sequencing methods, and genomic data analysis tools. CRISPR-Cas-based genome editing has opened a plethora of opportunities in agriculture as well as human health.

Morphogenic Regulators Baby boom and Wuschel Improve Monocot Transformation.

While transformation of the major monocot crops is currently possible, the process typically remains confined to one or two genotypes per species, often with poor agronomics, and efficiencies that place these methods beyond the reach of most academic laboratories. Here, we report a transformation approach involving overexpression of the maize (Zea mays) Baby boom (Bbm) and maize Wuschel2 (Wus2) genes, which produced high transformation frequencies in numerous previously nontransformable maize inbred lines. For example, the Pioneer inbred PHH5G is recalcitrant to biolistic and Agrobacterium tumefaciens transformation. However, when Bbm and Wus2 were expressed, transgenic calli were recovered from over 40% of the starting explants, with most producing healthy, fertile plants. Another limitation for many monocots is the intensive labor and greenhouse space required to supply immature embryos for transformation. This problem could be alleviated using alternative target tissues that could be supplied consistently with automated preparation. As a major step toward this objective, we transformed Bbm and Wus2 directly into either embryo slices from mature seed or leaf segments from seedlings in a variety of Pioneer inbred lines, routinely recovering healthy, fertile T0 plants. Finally, we demonstrated that the maize Bbm and Wus2 genes stimulate transformation in sorghum (Sorghum bicolor) immature embryos, sugarcane (Saccharum officinarum) callus, and indica rice (Oryza sativa ssp indica) callus.