Gene editing can prevent Eucalyptus from invading native ecosystems, research shows
By People Daily, April 19, 2021By Joseph Maina
Eucalyptus, one of Kenya’s most important trees valued for its hardy timber, wood fuel and medicinal extracts, can be genetically modified to prevent it from invading native ecosystems, a team of international researchers has shown.
Professor Steve Strauss from Oregon State University in the US led a team of scientists in the research, which concluded that the tree can be genetically modified not to reproduce sexually, through the CRISPR Cas9 gene editing technique.
The scientists have used CRISPR Cas9 to knock out to knock out LEAFY, the principal gene behind flower formation.
“The flowers never developed to the point where ovules, pollen or fertile seeds were observed,” Strauss said.
“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 stability of the vegetative and floral sterility traits, but with physical gene mutation we expect high reliability over the life of the trees.” CRISPR, pronounced “crisper”, is an acronym for “clustered regularly interspaced short palindromic repeats”.
CRISPR-Cas9 enables geneticists and medical researchers to edit parts of the genome by removing, adding or altering sections of the DNA sequence. Through the technique, researchers have the ability to make highly accurate changes in the DNA sequence of a living organism, basically customizing its genetic makeup.
“This could be a great means to prevent future spread from new plantings,” Professor Strauss told the People Daily.
“Our work or something similar could be very useful for this goal, with the main barriers being GMO regulations that might make it hard to get authorized in some countries, as well as the costs of making the GMOs in labs – given that governments might be the ones to do this. There would also be the challenges to genetic modification of many eucalypt species, which is often biologically difficult.”
Strauss, Ph.D. student Estefania Elorriaga and research assistant Cathleen Ma teamed up with scientists from the University of Colorado, Beijing Forestry University, and the University of Pretoria in the research. The greenhouse study involved a hybrid of two species, Eucalyptus grandis and E. urophylla, that is widely planted in the Southern Hemisphere.
“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,” said Elorriaga, a postdoctoral researcher at North Carolina State.
Those plantings can lead to undesirable mingling with native ecosystems, note the scientists. Thus, eliminating those trees’ ability to sexually reproduce without affecting other characteristics would be an effective way to greatly reduce the potential for invasive spreading in areas where that is considered an important ecological or economic problem.
In Kenya, this important tree species is reputed for its voracious appetite for water at the expense of other plant species. According to the Kenya Forestry Research Institute (KEFRI), eucalyptus is ranked among major commercial forestry species in the country, alongside cypress, pines and Grevillea. As at 2009, statistics showed that the area under eucalyptus in the country stood at 100,000 hectares.
Among its contributions to the national economy, eucalyptus provides power transmission poles for the expanded rural electrification programme and is an alternative source of affordable industrial energy for the tea, tobacco, lime, cement and many other industries.
It contributes to increased forest cover and contributes to carbon sequestration, which mitigates against climate change. Eucalyptus also provides additional services as windbreaks, shelterbelts and boundary demarcation.
The tree’s reputation has been subject of spirited campaigns to weed it out of wetlands, where it is considered unsuitable due to its perceived high water consumption.
Under the Agriculture (Farm Forestry) Rules, 2009 of the Agriculture Act, it is forbidden for any agricultural landowner or occupier to grow or maintain any eucalyptus species in wetlands and riparian areas.