Genome editing seems tailored for Italian agriculture as DNA can be modified without introducing foreign sequences and without destroying the legal identity of traditional cultivars. CRISPR could help developing plants more resistant to diseases, for example, avoiding at the same time bureaucracy and public perception problems that have slowed the adoption of GMOs. The stakes are high but some hurdles stand in the way. We have interviewed Michele Morgante, geneticist from the University of Udine and President of the Italian Society of Agricultural Genetics.
Is public research seizing the opportunities offered by CRISPR?
Italian teams already using the new technique on agrarian species can be counted on the fingers of one hand, the total increases including the model plant Arabidopsis thaliana. The main problem is not genetic modification but plant regeneration. Even if editing genomes has never been easier, we still need to regenerate whole plants from the edited cells via somatic embryogenesis.
Aren’t old in vitro culture methods keeping up with advances in genome editing?
Exactly. If a variety is easy to manipulate, you may edit that one and then transfer the edited trait into the preferred variety by crossing them. In order to get vines resistant to powdery mildew you can begin working with Brachetto or Sangiovese and then cross them with more reluctant varieties, but many unwanted traits will be inherited in this way from the donor plant. Therefore if the aim is to preserve the genetic identity of a commercial cultivar, crossing is not the solution.
Is it a surmountable problem?
The Nobel prize Shinya Yamanaka discovered how to get induced pluripotent stem cells in animal organisms and a similar phenomenon of totipotency should be induced in plants. A paper recently published in Plant Cell makes me hopeful. By over-expressing two factors called Baby boom e Wuschel, Pioneer researchers succeeded in transforming reluctant genotypes but only in monocot crops not in dicots. Maybe we only need time. Anyway it’s nice to see that they used the biolistic method, by hitting cells with gold particles coated with the above-mentioned factors and CRISPR components (the Cas enzyme and the RNA guide). In fact no foreign DNA integration was needed.
What could be done to improve grapevine?
Editing could be useful to improve qualitative traits. Resistance to powdery mildew is difficult to edit because you have to find an endogenous gene and change it. Alternatively genes for susceptibility could be targeted, for example the Edmund Mach Foundation has identified a natural mutation of a trans-membrane protein preventing infection, but the gene function is unknown. If this approach should succeed it would be a real progress for production.
No risk to worry about?
If the gene has any unknown useful function, we cannot exclude that edited vines will get into trouble in particular conditions. If it were an annual plant, only one harvest would be wasted. Vineyards however last for decades and you could end up regretting the editing in the meantime. By targeting resistance mechanisms rather than susceptibility, however, the worst case scenario is less worrying, you would just have plants that can be infected again. We have identified a gene for resistance to downy mildew and another one for resistance to powdery mildew, but they should be transferred by cisgenesis instead than edited.
What is cisgenesis?
It’s a classic genetic engineering procedure where the inserted DNA fragment originates from the same species or a sexually compatible species as the recipient organism. This is why the resulting plant is called cisgenic rather than transgenic, and this is why the Italian Society of Agricultural Genetics argues cisgenic crops should not been considered GMOs. Further genes for resistance have been identified by Australian researchers, therefore multi-resistant vines could be developed.
EU has not decided yet how to regulate these plants. What do winemakers think, are they interested anyway?
Viticulturists and producers did show interest in genome editing and cisgenesis alike. They are not being deterred by the lack of clear rules. The philosophy is let’s begin working on that now, then when the research bears fruit in 5 years time the regulatory impasse will be hopefully over.
Any other example of application fit for the agriculture of Mediterranean countries?
Citrus and olive are good examples. They represent valuable genotypes and CRISPR would be very useful to improve them by avoiding complex crosses. Think of oranges, it’s a single genotype created by interspecific crossing, this means that crossing it again, you wouldn’t get an orange anymore.
Which countries lead the way in editing plants?
I would say US, UK and Germany. It will be interesting to watch France as it is hostile to GMOs but also proud of Emmanuelle Charpentier, the French researcher who co-invented CRISPR. Unfortunately in the last 20 years agbiotech research in Italy has been seriously damaged by the campaign against genetic engineering and we need to make up for the delay.
Agbiotech geopolitics is going to be changed by CRISPR?
Researchers should keep on exchanging information and plant genetic resources. The Nagoya Protocol on access and benefit sharing could be problematic if strictly applied, in comparison with the Fao Treaty. Science must stay open and regulations should better take into account that researchers don’t need to ask germplasm banks for the seeds in order to edit genomes, accessing sequences in DNA databases is enough. That’s a real change.