Previously known for contributing to fruit color and shape, rider retrotransponsons, or jumping genes, have been found to alter the gene expression and physical characteristics of plants. Recent studies conducted by the Sainsbury Laboratory (SLCU) of the University of Cambridge and the Department of Botanical Sciences in the United Kingdom suggest that the natural regeneration properties of jumping genes may alter the characteristics of fruits and vegetables. This can make crops better able to cope with more extreme conditions brought about by climate change, such as helping them fight drought.

Dr. Matthias Benoit, the paper’s first author, formerly at SLCU, tells FoodIngredientsFirst that scientists are at the very beginning of this field of research. “Transposons (jumping genes) carry huge potential for crop improvement. Our research, together with the work of the community, provides a better understanding of how to control them. Further molecular work might offer a promising method to facilitate the occurrence of new phenotypes, such as fruit color, shape or resilience to environmental stresses.”

For much of the 20th century, genes were considered to be stable entities arranged in an orderly linear pattern on chromosomes. This research has shown, however, that jumping genes are mobile snippets of DNA code that can copy themselves into new positions within the genome, the genetic code of an organism. They can change, disrupt or amplify genes, or have no effect at all. 

Using them more purposefully would revolutionize traditional plant breeding techniques and maximize yields. They could enable the production of a plethora of new plant traits, such as shape, color or size, which could then be refined and optimized by gene targeting technologies. 

“In a large population size, such as a tomato field, in which transposons are activated in each individual, we would expect to see an enormous diversity of new traits. By controlling this ‘random mutation’ process within the plant, we can accelerate this process to generate new phenotypes that we could not even imagine,” says Dr. Hajk Drost of SLCU, a co-author of the paper.

Easier said than done
Although there is vast potential in this field of research, there are also many challenges. Dr. Benoit explains that it is challenging to identify all the jumping genes contained within the genome reliably. Moreover, each family of jumping genes is unique – while some jumping genes move using a copy-and-paste approach, others use a cut-and-paste. The environment or temperature activates some genes, while others are stimulated at a specific time in its plant’s development. 

“The genome of crop plants are very complex since they contain a large proportion of repetitive sequences. If we use a puzzle analogy, it means that on average, 50 percent of the puzzle pieces will be very similar, if not identical. That makes the puzzle extremely hard to assemble. Our work therefore relies on the availability of high-quality genomic resources,” Dr. Benoit explains. 

Future prospects
Nobel-prize winner Barbara McClintock first discovered jumping genes in corn kernels in the 1940s. Her research is now coming to the fore because it previously required the development of an entire computational toolkit to characterize the abundance, scope and function of this family of jumping genes, says Dr. Benoit. 

The debate on gene editing technology and its legal restrictions has recently been gaining speed. Research has shown that the rules on genetically modified organisms (GMO) are so restrictive that it is virtually impossible to attain authorization for cultivating a GMO crop within the EU. Scientists across Europe are calling for a rethink on the restriction of genome editing technology by the European Parliament and European Commission. Many EU scientists and plant breeders advocate for permitting genome editing with CRISPR as a faster and more efficient way of producing food sustainably. 

Similarly, Greg Ibach, Under Secretary of the US Department of Agriculture (USDA), hinted that gene-editing methods should be allowed within organic production. The comments he made before the House Agriculture Subcommittee could lead to a loosening of the restrictive GMO legislation, long-called for by both scientists and the Trump administration. 

Nevertheless, the future holds much in store for further research on jumping genes. “The constantly increasing availability of high-quality crop genomes provide an unprecedented opportunity for geneticists and molecular biologists to understand the phenomena beyond the amazing diversity in crop traits. We can now identify the molecular causes of traits of interest, such as plant structure, yield, fruit shape or size. This will certainly help nurture the crops we need in the face of uncertainties about the future, "Dr. Benoit concluded.