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A hidden gene from a wild banana plant could help save the world’s favorite fruit from a relentless fungal threat.
Scientists have identified a powerful source of natural resistance to a fungal disease threatening banana plantations around the world, discovering it in a wild subspecies of the fruit.
Researchers at the University of Queensland, led by Andrew Chen e Elizabeth Aitkenlocated the specific genomic region responsible for resistance to fusariosis of Subtropical Race 4 (STR4), a devastating strain of the so-called “Panama disease”, which can cause
The discovery, presented in a recently published in the journal Horticulture Researchrepresents a significant advance for programs seeking long-term solutions to this growing agricultural threat.
“Fusarium wilt, also known as Panama disease, is a destructive disease of telluric origin that affects Cavendish banana trees cultivated around the world through its virulent Race 4 strains,” said Andrew Chen, quoted by .
The team traced the resistance trait to a wild diploid banana plant known as Calcutta 4. To identify the genetic origin, they crossed Calcutta 4 with susceptible banana trees from another subspecies within the group of diploid banana plants.
“We have located the source of STR4 resistance in Calcutta 4which is a highly fertile wild diploid banana plant, by crossing it with susceptible banana plants from a different subspecies of the diploid banana group,” Chen explained.
After the resulting plants grew, the researchers exposed them to STR4. “After exposing the new progeny plants to STR4, we examined and we compared the DNA of those who succumbed to the pathogen with those that resisted.
“We mapped resistance to STR4 on Calcutta 4 chromosome 5. This is a very significant finding; it is the first genetic dissection of resistance to Race 4 from this wild subspecies”, notes Chen.
Each new generation of banana crosses had to grow for at least 12 months before scientists could test it for disease resistance and proceed with breeding after flowering.
The discovery lays the foundation for the development of commercial banana varieties capable of resisting fusariosis. “Although Calcutta 4 provides crucial genetic resistance, not suitable for commercial cultivationsince it does not produce fruits of quality for consumption”, adds the researcher.
“The next step is to develop molecular markers to screen the resistance trait efficiently so that plant breeders can select seedlings early and accurately, before any disease symptoms appear,” says Chen.
“This will speed up selection, reduce costs and, hopefully, ultimately lead to a banana that is good to eat, easy to grow and naturally protected against fusariosis through its genetics,” he concludes.
