Scientists from Plant & Food Research and Lincoln University have contributed knowledge integral to the discovery of a new gene described as a game changer for global agriculture.
The gene allows natural reproduction by cloning in plants, allowing highly desirable traits to be carried through to the next generation rather than lost when the plants reproduce through pollination.
Scientists in New Zealand have been working with scientists in the Netherlands – at research company KeyGene and Wageningen University & Research (WUR) – and Japan – at breeding company Takii – to identify ways to produce plant seeds that are genetically identical to the parent plant.
The research was recently published in the prestigious journal Nature Genetics.
The newly-discovered gene, named PAR, controls parthenogenesis, a process whereby plant egg cells spontaneously grow into embryos without fertilisation. Normally, the PAR gene is triggered by fertilisation, but in plants that reproduce by apomixis – a type of reproduction which does not require fertilisation – the PAR gene switches on spontaneously, so the egg cells are triggered to start dividing into a new embryo.
“Being able to reproduce annual crops by apomixis would be a game-changer for farmers worldwide,” says Plant & Food Research scientist Dr Ross Bicknell. “For subsistence farmers in particular this would be revolutionary. Instead of always having to buy seed they would now be able to save their own and use it to grow plants with the same elite characteristics year on year without losing quality. That’s why this has the potential to be a truly empowering technology, giving autonomy to people who have the least.”
“Currently, creating seed for an annual plant, such as wheat or rice, requires pollination. As each seed combines genetic characteristics from two parent plants, no two seedlings are the same. Or to put it another way, only a very small number of plants in a field of wheat are the very, very best. Now imagine being able to produce a whole crop made up of just those elite individuals. Cloning is not actually an unusual idea, we already use it for things like fruit trees, grapes and strawberries, but this will bring the advantages of cloning to the crops that support humanity – and that really would be a game changer for agriculture,” Dr Bicknell says.
Plants that naturally reproduce by apomixis were found to have a transposon (a small piece of DNA that can jump around the plant DNA) in the promoter of the PAR gene. The promoter is the part of a gene which regulates that gene’s activity.
“It is very interesting to see a transposon involved in such a key process in two independent species,” said Lincoln University’s Associate Professor Chris Winefield. “Transposons are often proposed to be involved in evolution of plants and animals so to see a transposon driving a key process such as apomixis is very exciting”.
Researchers at KeyGene have already started researching whether the PAR gene can cause parthenogenesis in plants that do not normally reproduce by apomixis, such as lettuce and sunflower, to further understand how this gene could be used in crop plant breeding.
The New Zealand scientists started studying parthenogenesis about 25 years ago in hawkweed, a plant that was once studied extensively by Gregor Mendel, the grandfather of genetics. This research is now combined with similar research in dandelion in the Netherlands. Together with the DIP gene, which ensures that the number of chromosomes is not halved during the formation of egg cells, and which was discovered previously by KeyGene, the PAR gene generates apomixis.
Note: For perennial crops, such as kiwifruit and apple, new plants are already cloned by taking a graft from a parent plant, which retains the parent’s characteristics in the new individual.