Highly Efficient Gene Knockout in Medicago truncatula Genotype R108 Using CRISPR-Cas9 System and an Optimized Agrobacterium Transformation Method.

Medicago truncatula is the model plant species for studying symbioses with nitrogen-fixing rhizobia and arbuscular mycorrhizae, where edited mutants are invaluable for elucidating the contributions of known genes in these processes. Streptococcus pyogenes Cas9 (SpCas9)-based genome editing is a facile means of achieving loss of function, including where multiple gene knockouts are desired in a single generation. We describe how the user can customize our vector to target single or multiple genes, then how the vector is used to make M. truncatula transgenic plants containing target site mutations. Finally, obtaining transgene-free homozygous mutants is covered.

Correction to: An efficient and reproducible Agrobacterium- mediated transformation method for hexaploid wheat (Triticum aestivum L.).

[This corrects the article DOI: 10.1186/s13007-019-0503-z.].

An efficient and reproducible Agrobacterium-mediated transformation method for hexaploid wheat (Triticum aestivum L.).

BACKGROUND: Despite wheat being a worldwide staple, it is still considered the most difficult to transform out of the main cereal crops. Therefore, for the wheat research community, a freely available and effective wheat transformation system is still greatly needed. RESULTS: We have developed and optimised a reproducible Agrobacterium-mediated transformation system for the spring wheat cv 'Fielder' that yields transformation efficiencies of up to 25%. We report on some of the important factors that influence transformation efficiencies. In particular, these include donor plant health, stage of the donor material, pre-treatment by centrifugation, vector type and selection cassette. Transgene copy number data for independent plants regenerated from the same original immature embryo suggests that multiple transgenic events arise from single immature embryos, therefore, actual efficiencies might be even higher than those reported. CONCLUSION: We reported here a high-throughput, highly efficient and repeatable transformation system for wheat and this system has been used successfully to introduce genes of interest, for RNAi, over-expression and for CRISPR-Cas9 based genome editing.

Understanding differences in access to water fountains and sugar-sweetened beverages in children׳s environments: a pilot study in high and low deprivation neighbourhoods.

Access to water fountains and sugar-sweetened beverages (SSBs) in children׳s environments may impact on child obesity and may vary with neighbourhood deprivation. Our pilot analyses of access to water fountains and SSBs in Wellington, New Zealand revealed that water fountain access was high in school environments and low in recreational environments. There were also differences in water fountain and SSB access points by neighbourhood deprivation. The methods piloted in this study could be translated in a larger study, more capable of detecting significant differences in access and allowing for more sophisticated analyses. Such future studies may provide important evidence for the improvement of children׳s health and well-being.