The field of genetic engineering has taken a significant leap forward with the development of two new genome editing technologies by a team of Chinese researchers led by Prof. Gao Caixia from the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences. These innovations, collectively known as Programmable Chromosome Engineering (PCE) systems, have been published in the prestigious journal Cell.

The PCE system is an upgrade to the well-known Cre-Lox technology, which has long been used for precise chromosomal manipulation. However, this older method had three major limitations that hindered its broader application: low recombination efficiency, reversible recombination activity, and the need for a scar (a small DNA fragment) at the editing site.

The research team tackled each of these challenges by developing novel methods to advance the state of this technology. Firstly, they created a high-throughput platform for rapid recombination site modification and proposed an asymmetric Lox site design that reduces reversible recombination activity by over 10-fold.

Secondly, they utilized their recently developed AiCE model – a protein-directed evolution system integrating general inverse folding models with structural and evolutionary constraints – to develop AiCErec. This approach enabled precise optimization of Cre’s multimerization interface, resulting in an engineered variant with a recombination efficiency 3.5 times that of the wild-type Cre.

Lastly, they designed and refined a scarless editing strategy for recombinases by harnessing the high editing efficiency of prime editors to develop Re-pegRNA, a method that uses specifically designed pegRNAs to perform re-prime editing on residual Lox sites, precisely replacing them with the original genomic sequence.

The integration of these three innovations led to the creation of two programmable platforms, PCE and RePCE. These platforms allow flexible programming of insertion positions and orientations for different Lox sites, enabling precise, scarless manipulation of DNA fragments ranging from kilobase to megabase scale in both plant and animal cells.

Key achievements include targeted integration of large DNA fragments up to 18.8 kb, complete replacement of 5-kb DNA sequences, chromosomal inversions spanning 12 Mb, chromosomal deletions of 4 Mb, and whole-chromosome translocations. As a proof of concept, the researchers used this technology to create herbicide-resistant rice germplasm with a 315-kb precise inversion.

This groundbreaking work not only overcomes the historical limitations of the Cre-Lox system but also opens new avenues for precise genome engineering in various organisms, demonstrating its transformative potential for genetic engineering and crop improvement.

The mystery of where potatoes came from has been solved by an international research team. Scientists have uncovered that 9 million years ago, a natural interbreeding event occurred between tomato plants and potato-like species from South America, giving rise to the modern-day potato. This ancient evolutionary event triggered the formation of the tuber, the enlarged underground structure that stores nutrients in plants like potatoes, yams, and taros.

The research team analyzed 450 genomes from cultivated potatoes and 56 wild potato species to solve this long-standing mystery. They found that every potato species contained a stable mix of genetic material from both Etuberosum and tomato plants, suggesting an ancient hybridization between the two. The team also traced the origins of the potato’s key tuber-forming genes, which are a combination of genetic material from each parent.

The discovery reveals how a hybridization event can spark the evolution of new traits, allowing even more species to emerge. This is particularly significant in the context of one of the world’s most important crops, the potato. As one of the world’s most widely cultivated foods, potatoes have long puzzled scientists with their seemingly identical appearance to Etuberosum plants but lack of tubers.

To fill this knowledge gap, researchers analyzed 450 genomes from cultivated potatoes and 56 wild potato species. They found that every potato species contained a stable mix of genetic material from both Etuberosum and tomato plants. This suggests an ancient hybridization event occurred between the two, which gave rise to the modern-day potato.

The team’s findings also reveal how this ancient evolutionary innovation coincided with the rapid uplift of the Andes mountains. As new ecological environments emerged, early potatoes were able to quickly adapt and survive in harsh weather conditions using their tubers as a nutrient storage system. This allowed them to rapidly expand and fill diverse ecological niches from mild grasslands to high and cold alpine meadows in Central and South America.

The discovery of the potato’s ancient origins is a significant breakthrough in understanding how new species emerge. It highlights the importance of natural interbreeding events in shaping the evolution of plants and their adaptation to changing environments.

The article highlights groundbreaking research conducted at Edith Cowan University, where scientists have discovered an innovative way to extend the storage life of mangoes by up to 28 days. Led by Dr Mekhala Vithana, the study reveals that dipping mangoes in ozonated water for 10 minutes before cold storage significantly reduces chilling injury and extends shelf life.

Mango lovers rejoice! The research is a game-changer for growers and traders alike, as it reduces food loss during storage and provides a longer market window. With the global demand for fruits and vegetables on the rise, this eco-friendly technology could minimize post-harvest losses of mangoes and reduce waste in Australia.

Traditionally, mangoes are stored at 13 degrees Celsius for up to 14 days, but this temperature is not cold enough to prevent chilling injury. Prolonged storage below 12.5 degrees causes physiological disorders that damage the fruit skin and lead to decreased marketability and significant food waste.

The study tested aqueous ozonation technology on Australia’s most widely produced mango variety, Kensington Pride, and found that dipping the mango in ozonated water for 10 minutes prior to cold storage at 5 degrees Celsius extended shelf life up to 28 days with much less chilling injury. This breakthrough could revolutionize the way we store mangoes and reduce food waste.

Dr Vithana emphasizes that aqueous ozonation is a cost-effective, controlled-on-site technology that can be used in commercial settings. The researchers hope to conduct further studies on other varieties of mangoes to test their responsiveness and achieve further reduction in chilling injury for extended cold storage.

As we continue to explore innovative solutions to reduce food waste, the ozone secret could hold the key to extending mango storage life by 28 days, benefiting both growers and consumers alike.