Gene-Edited Citrus Comes Closer to Commercial Realization

In 2012, Jennifer Doudna, Emmanuelle Charpentier and their research team published a paper in the journal Science describing the CRISPR-Cas9 system as a precise gene-editing tool. It was considered a major scientific breakthrough with huge possibilities in human medicine and in agriculture. Doudna and Charpentier were awarded the Noble Peace Prize in chemistry in 2020 for their pioneering work with CRISPR.

A little over a decade after the paper was published, the potential of CRISPR is beginning to unfold. Nian Wang, J.R. (Rip) Graves eminent scholar endowed chair with the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS), saw the potential of CRISPR to help Florida citrus growers in the fight against HLB. Could the technology be used to create a citrus tree resistant to the disease?

He began his research on CRISPR genome editing in 2013, making his laboratory the first to gene-edit citrus in the world. Thus began the journey for the microbiologist to develop a gene-edited tree capable of resisting the disease that has reduced citrus production by more than 90% in Florida.

Since his research began, Wang has generated more than 200 citrus lines with 40 targeted genes aiming to improve HLB tolerance or resistance. Some of these citrus plants for the two most promising targets are now moving into evaluation in grove trials.

GROUP 1 PLANTS

Wang has separated these most developed lines into two plant groups. The plants furthest along are in group one of CRISPR gene-edited sweet oranges. They are Valencia Super UFW1 and Hamlin Super UFW3 (temporary names for genome-edited lines of the Eds1 gene). There are more than five lines/varieties with both plant types.

“These plants were inoculated with the HLB bacteria in May in the greenhouse through psyllid transmission. We should get the data related to tolerance/resistance before the end of 2025,” Wang says. “The plants need to grow bigger before we can conduct field trials. Field trials are important for us to have a good understanding about their performance against HLB and other horticultural traits. But our previous studies suggest Valencia Super UFW1 and Hamlin Super UFW3 are likely tolerant to HLB without obvious HLB symptoms when infected.”

All these plants must go through regulatory approval before being released to growers for commercial planting. The good news from the U.S. Department of Agriculture (USDA) is that both plants are considered non-GMO and are therefore not regulated. Read the rest of the article and see a video explanation of CRISPR here.