Variation in floral form of CRISPR knock-outs of the poplar homologs of and after FT heat-induced early flowering.

Plant migration and gene flow from genetically modified or exotic trees to nearby lands or by crossing with wild relatives is a major public and regulatory concern. Many genetic strategies exist to mitigate potential gene flow; however, the long delay in onset of flowering is a severe constraint to research progress. We used heat-induced FT overexpression to speed assessment of the expected floral phenotypes after CRISPR knockout of poplar homologs of the key floral genes, and .

Knockout of floral and meiosis genes using CRISPR/Cas9 produces male-sterility in Eucalyptus without impacts on vegetative growth.

spp. are widely cultivated for the production of pulp, energy, essential oils, and as ornamentals. However, their dispersal from plantings, especially when grown as an exotic, can cause ecological disruptions.

The Game of Timing: Circadian Rhythms Intersect with Changing Environments.

Recurring patterns are an integral part of life on Earth. Through evolution or breeding, plants have acquired systems that coordinate with the cyclic patterns driven by Earth's movement through space. The biosystem responses to these physical rhythms result in biological cycles of daily and seasonal activity that feed back into the physical cycles.

Genetic containment in vegetatively propagated forest trees: CRISPR disruption of LEAFY function in Eucalyptus gives sterile indeterminate inflorescences and normal juvenile development.

Eucalyptus is among the most widely planted taxa of forest trees worldwide. However, its spread as an exotic or genetically engineered form can create ecological and social problems. To mitigate gene flow via pollen and seeds, we mutated the Eucalyptus orthologue of LEAFY (LFY) by transforming a Eucalyptus grandis × urophylla wild-type hybrid and two Flowering Locus T (FT) overexpressing (and flowering) lines with CRISPR Cas9 targeting its LFY orthologue, ELFY.

Variation in Mutation Spectra Among CRISPR/Cas9 Mutagenized Poplars.

In an effort to produce reliably contained transgenic trees, we used the CRISPR/Cas9 system to alter three genes expected to be required for normal flowering in poplar (genus ). We designed synthetic guide RNAs (sgRNAs) to target the poplar homolog of the floral meristem identity gene, (), and the two poplar orthologs of the floral organ identity gene (). We generated 557 transgenic events with sgRNA(s) and the Cas9 transgene and 49 events with Cas9 but no sgRNA, and analyzed all events by Sanger Sequencing of both alleles.