Thursday, April 8th 2021, 11:59 am - Researchers hope the study will demonstrate how safe the technology used can be.
Image of a modified set of eucalypt floral buds that do not develop further to make viable pollen or seeds (main image and lower right), compared to wild type flower buds (upper right) and open flower (middle right). Photo and caption courtesy: OSU College of Forestry
Eucalyptus has its benefits. It's a pest-resistant evergreen with durable lumber and oil used to reduce pain and inflammation. But in some places, like along the California coast, eucalyptus is invasive. When growing in non-native locales, it can alter soil moisture and forest fire patterns.
Now, an international collaboration led by Oregon State University's Steve Strauss has found the CRISPR Cas9 gene-editing technique can be used to modify a eucalyptus gene referred to as LEAFY, which promotes flower formation.
It is the first time CRISPR has been used to solve an issue with commercial forest trees.
CRISPR stands for “Clustered Regularly Interspaced Short Palindromic Repeats.” It is genome engineering technology that allows scientists to easily edit the DNA of any genome with precision.
Researchers said the gene-modifying technique works with "nearly 100 per cent efficiency," and could prevent eucalyptus from reproducing and invading non-native ecosystems.
"The flowers never developed to the point where ovules, pollen, or fertile seeds were observed," Strauss said in a statement.
"And there was no detectable negative effect on tree growth or form. A field study should be the next step to take a more careful look at the stability of the vegetative and floral sterility traits, but with physical gene mutation we expect high reliability over the life of the trees."
Estefania Elorriaga, a postdoctoral researcher at North Carolina State, says the findings are important given the prevalence of eucalyptus in non-native regions.
Though originally from Australia and New Zealand, eucalyptus plantations have popped up in several countries. They take in large amounts of water, leaving the soil dry, and are sometimes referred to as 'green deserts.'
"Roughly 7 per cent of the world's forests are plantations, and 25 per cent of that plantation area contains nonnative species and hybrids," Elorriaga says.
"Eucalyptus is one of the most widely planted genera of forest trees, particularly the 5.7 million hectares of eucalyptus in Brazil, the 4.5 million hectares in China, and 3.9 million hectares in India."
And while those plantings are intentional, they can contribute to "undesirable mingling" with native plants. Preventing their ability to reproduce without impacting other aspects of the plants presents a solution, researchers say.
But there may be legal hurdles with getting the product to market. The study's authors point to Brazil, which has legislation in place making it illegal to plant genetically modified vegetation.
The modified eucalyptus "would also be disallowed for field research or commercial use under sustainable forest management certification in many parts of the world," Strauss says. "[This is] something scientists have come together to severely criticize in recent years."
Strauss hopes the findings will demonstrate that modifying plant traits can be safe and promote ecological safety.
"Happily, such discussions are well underway in many nations," he adds.
The research has been published in Plant Biotechnology Journal.