Using gene technology for improving crop morphology for protected environments

Context: Climate change, soil erosion and issues associated with chemical control of pests/diseases under field conditions is driving interest in cultivating selected crops in protected environments as well as controlled environments such as indoor farms.

There are many benefits associated with fully controlled indoor environments such as vertical farm systems: 1) rapid crop development, 2) reduced water/nutrient/pesticide inputs, and 3) reduced food miles.

To date, most commercially-active indoor farms have focused on microgreens or baby leaf salad crops, but there is potential to grow more crop types. Growers are now keen to develop highly controlled environments as an alternative to field grown crops for increased local production. However, unlike field-grown crop varieties, there has been limited research or breeding efforts to develop crops for such environments.

Despite fast, healthy development of many crops in vertical farms, plant structure/architecture is not optimised. Breeders have selected varietal genotypes for field or glasshouse cultivation conditions over many decades. As yet, very little focussed breeding/selection has been undertaken for different indoor cultivation conditions and other protected environments.

Typically, plant factories employ one of two main design styles:

1)-Layers of stacked horizontal growing platforms;

2)-Vertical units stacked in parallel, with LED lighting between layers.

Horizontal systems limit crop-height, and whilst vertical systems better accommodate taller crops, pilot studies with chillies and cucumbers in aeroponic systems resulted in sub-optimal crop architecture, with inefficient twisted stems and long dropping fruit. Crop cultivation could be significantly improved through use of bushier, dwarf plants.

Challenges: Breeding or selecting cultivars with dwarf phenotypes is a lengthy process, which has taken decades using conventional breeding approaches. Meeting the challenge of growing crops with alternative structural architecture for protected environments requires rapid innovation via use of modern genetic improvement strategies. The agricultural Green Revolution of the 1950/60s delivered dwarf varieties of our major arable crops, which resulted in increased global crop yields. Genes responsible for dwarfing wheat plants are known and involve production of the plant hormone Gibberellic Acid (GA). To date, application of this knowledge is restricted to the development of field-grown crops, and has never been exploited for commercial horticultural crops (notably tall pepper and cucumber families).

We will exploit this knowledge alongside state-of-the-art genome editing (GE) techniques to produce dwarf peppers and cucumbers for aeroponic controlled environments and protected glasshouses.

Project objectives:

Exploit CRISPR GE technology to knock-out GA genes in pepper and cucumber to produce dwarf plants.
Use grafting approaches to remove CRISPR elements in peppers.
Assess the impact of gene manipulation on plant phenotypes.
Test selected lines for growth/yield in indoor farms and a commercial glasshouse to evaluate commercial benefits.
This will be one of the first studies to use CRISPR to manipulate plant architecture for protected environments. Furthermore, development of the technology and approach has numerous applications and benefits: 1) Proof-of-concept for use of GE technology to develop plants with the appropriate morphologies and traits for innovative indoor growth environments; 2) Exemplar for a much wider range of applications to improve plant phenotypes for new growing environments; 3) Demonstration of industrial potential for the use of grafting techniques to increase early growth rate via removal of CRISPR markers. Together these provide significant advancements for developing PACE cropping.