The genetic control of crop growth and behaviour can be modified through traditional plant breeding or genetic engineering, but is fixed once a variety is sown. New spray-on viral transfection technology can transiently alter gene expression to “fine-tune” agronomic traits within the season while avoiding modifications to the genome, write Karen Massel, Ian Godwin and Lee Hickey at the The University of Queensland in Australia.
They say that modern plant improvement programmes have yielded substantial productivity gains across broadacre and horticultural cropping systems. The ability to match a genotype with environment and management practices has enabled increasingly sophisticated cropping scenarios to overcome biotic and abiotic stresses and to close yield gaps. Once the crop is planted, the genotype is fixed and many of the management decisions have already been made, such as land preparation, planting date and plant density.
But environment remains ‘the great unknown’ and with climate change in action across the globe, forecasting temperature and rainfall is becoming more challenging. Hence during the crop cycle, management tools such as pesticides, fertilizers and plant growth regulators remain the only available options to modify crop growth and resilience.
However, in this issue of Nature Plants, Torti et al. demonstrate that the regulatory circuits controlling crop growth and development can be altered transiently during the lifecycle of plants. They redesigned techniques of gene delivery, amplification and expression around RNA viral transfection methods that can be implemented on an industrial scale and with many crop plants.
For crop production, the technology could provide a new management tool to tune agronomic performance post hoc. Depending on local weather conditions, key genes in developmental pathways could be selectively reprogrammed.