Generation of parthenocarpic Solanum melongena plants using CRISPR-Cas9 mediated editing

Parthenocarpy is an important sought-after trait in many horticultural crops which provides higher fruit quality for both the direct market and industrial processing, as the occurrence of seedless fruits increases consumer acceptance and maintains prolonged fruit flesh texture, firmness and color.
In eggplant (Solanum melongena L.) berries must be harvested at commercial ripening stage well before physiological ripening, as this latter coincides with the presence of mature seeds which strongly decreases the commercial value of the fruits or even make them unmarketable.
The obtainment of parthenocarpic lines for this crop would allow the production of high-quality eggplant fruits, increase the time window for their harvesting and save cultivation costs, promoting fruit set also under unfavorable conditions for pollinators.
To this end, we carried out a CRISPR-Cas9 mediated editing exercise to generate mutated eggplant lines in several target genes known in literature to cause fertilization-independent fruit set in other species.
Primary targets have been genes involved in auxin metabolism and transport in the bud, and included PAD-1, transcription factors AGL6, AGL11, ARF8, IAA9 and the two AUCSIA genes.
For some candidates, the outcome of editing-induced loss-of-function mutations was already predictable considering the effects obtained in eggplant with traditional transgenic approaches or in edited tomato.
We achieved editing for all these targets in different eggplant backgrounds with some dramatic outcomes, as for some targets several T₀ transgenic plants already displayed complete parthenocarpic fruit development and the absence of seeds.
Even though, in some cases, loss-of-function editing mutations also affected pollen viability, either self-pollination or backcross of IAA9, ARF8, AGL11 and both AUCSIAs T₀ edited lines yielded a reduced number of seeds.
The development of Cas9-negative T₁ plants with stable homozygous mutation in either AUCSIA targets was carried out, while selection of Cas9-free T₁ plants homozygous for mutations at other target genes is underway.

International Symposium on Biotechnological Tools in Horticulture

L. Toppino, S. Gattolin, M.R. Tassone, M.T. Azzimonti, G.L. Rotino

eggplant, parthenocarpy, seedless, AUCSIA genes, auxin

https://doi.org/10.17660/ActaHortic.2026.1454.2