As GAIN4CROPS concludes, the project’s roadmap offers a rare, evidence-based view of what enables — and what limits — progress in photosynthesis and photorespiration engineering. The lessons below are grounded in experimental results, modelling, and comparisons with large international initiatives.
1. Genetic engineering delivers impact faster than natural variation alone
GAIN4CROPS confirmed that natural genetic variation influencing photosynthesis exists, but exploiting it through breeding remains slow and constrained by breeding cycles, hybrid compatibility, and limited access to diversity. By contrast, synthetic biology and genetic engineering enable targeted, transferable interventions on climate-relevant timescales. For example South et al. (2019 – https://doi.org/10.1126/science.aat9077 ) provide field evidence that engineered interventions can generate climate-relevant yield impacts within a few years, compared with the much longer timelines usually needed for breeding-based exploitation of natural variation.
Lesson: breeding remains essential long-term, but engineering is indispensable for timely impact.
2. Plant transformation — not pathway design — is the main bottleneck
In GAIN4CROPS, implementation was limited less by pathway feasibility than by access to transformation technologies, particularly in sunflower. Efficient methods exist but are often proprietary or restricted to specific genotypes.
This contrasts with maize, where service-based infrastructures exist. The Crop Genome Engineering Facility at VIB-UGent (https://www.psb.vib-ugent.be) allows external users to submit constructs and receive transformed maize or soybean lines, demonstrating that transformation can function as shared research infrastructure.
Lesson: without open, accessible transformation platforms, translation stalls — regardless of scientific creativity.
3. Stepwise translation and proxy crops reduce failure risk
GAIN4CROPS adopted a stepwise pipeline: modelling → microbes → model plants → crops. While Arabidopsis thaliana remains indispensable for mechanistic studies, the project demonstrated that the leap from Arabidopsis directly to sunflower is often too large to ensure transferability.
Tobacco emerged as a valuable proxy crop, combining high transformability with crop-like growth, dense canopy formation, and physiological properties that better approximate field crops than small laboratory models. This strategy mirrors the RIPE programme (https://ripe.illinois.edu) where tobacco was used to validate photosynthetic enhancements before transfer to rice and other staple crops.
Lesson: intermediate prototyping is not a delay — it is essential for scalable innovation.
4. Field trials and regulation determine scale-up
Meaningful scale-up in sunflower cannot proceed without field trials generating agronomic, ecological, and economic data. Current regulatory constraints in Europe Union limit such testing for GE/NGT crops. Gain4crops has engaged with the current policy debate on crop innovation [link to the Policy Debate news] and underlines the need for clear regulatory pathways so public research can translate into real agricultural practice.
Lesson: innovation timelines must match accelerating environmental pressures, and policies must remain coherent with broader sustainability strategies like the Green Dealthat enable experimentation and market approval in line with the sustainability strategies.
