In a rapidly changing climate landscape, the plants we rely on for food, textiles, and more face a multitude of challenges, including rising temperatures, drought, and disease. Caltech's Gözde Demirer, the Clare Boothe Luce Assistant Professor of Chemical Engineering, uses genetic engineering tools to make crops more resilient to such threats and enhance plant health. Now, she and a team of Caltech researchers have found a new solution to an old problem in an unlikely source: the zebra finch.
"For decades, plant engineering has largely relied on delivering DNA and hoping it lands in a useful place. We took inspiration from nature and turned a genetic element from a bird into a precise genome-writing system for plants," says Demirer, who is the corresponding author on a paper describing the team's findings published June 19 in Nature Biotechnology. "That shift from random insertion toward controlled genome installation could fundamentally expand how we design crops, study plant biology, and build plant-based technologies."
The DNA of living organisms provides instructions that tell them what to do and how to do it. These instructions come in the form of genes, which dictate plant traits, such as how tall a plant will grow. With the tools of genetic engineering, it is possible to enhance organisms by giving them new genes; a plant can be protected from thermal stress, for example, if it is given a gene with instructions that help it produce molecules that protect against heat.
For decades, researchers added new genes to plants using a soil bacterium Agrobacterium tumefaciens, which acts as a carrier for the genes and inserts them into a plant's genome. However, where the gene lands is random, so it may interrupt the function of a gene the plant needs or behave unpredictably. More precise tools such as CRISPR emerged in the early 2010s, but they still struggle to insert large DNA sequences accurately and efficiently in plants. So Demirer and her team turned to retrotransposons, genetic elements that can "copy and paste" new instructions efficiently to control cellular processes.
The R2 retrotransposon, a mobile genetic element found in many multicellular animals such as insects, crustaceans, and birds, uses the protein it encodes to copy cargo RNA into DNA directly at the target site in the genome. While researchers have turned them into a powerful gene-insertion tool in mammalian cells, whether the machinery could be made to work in plants was unknown.
Source : caltech.edu