Scientists discover gene that could save bananas from deadly Panama disease
Scientists have uncovered a powerful source of natural disease resistance in a wild banana, offering new hope for protecting
Scientists have uncovered a powerful source of natural disease resistance in a wild banana, offering new hope for protecting the global banana supply from a dangerous fungal threat.
Researchers at The University of Queensland, led by Dr. Andrew Chen and Professor Elizabeth Aitken, identified the specific genomic region responsible for resistance to Fusarium wilt Sub Tropical Race 4 (STR4), a destructive strain of Panama disease.
Fusarium Wilt and the Threat to Cavendish Bananas
“Fusarium wilt — also known as Panama disease — is a destructive soil-borne disease which impacts farmed Cavendish bananas worldwide through its virulent Race 4 strains,” Dr. Chen said.
This fungus attacks the plant through the soil, causing it to wilt and die. Even worse, it leaves behind long-lasting contamination in the soil, putting future crops at risk.
“Identifying and deploying natural resistance from wild bananas is a long-term and sustainable solution to this pathogen that wilts and kills the host plant leaving residue in the soil to infect future crops,” Dr. Chen explained.
Mapping Genetic Resistance in Wild Bananas
The team traced the source of resistance to a wild diploid banana known as Calcutta 4. To pinpoint the protective trait, researchers crossed Calcutta 4 with susceptible bananas from another diploid subspecies.
“We’ve located the source of STR4 resistance in Calcutta 4 which is a highly fertile wild diploid banana by crossing it with susceptible bananas from a different subspecies of the diploid banana group,” Dr. Chen said.
After growing the new plants, the scientists exposed them to STR4 and compared the DNA of plants that survived with those that became infected.
“After exposing the new progeny plants to STR4, we examined and compared the DNA of the ones which succumbed to the pathogen and those that didn’t.
“We mapped STR4 resistance to chromosome 5 in Calcutta 4.
“This is a very significant finding; it is the first genetic dissection of Race 4 resistance from this wild subspecies.”
A Five-Year Effort Using Advanced Genetics
The project, conducted through the School of Agriculture and Food Sustainability, required five years of work. Each generation of banana plants had to grow for at least 12 months before researchers could test them for disease resistance and continue breeding once they flowered.
To make the discovery, the team combined forward genetics (population development and disease screening), genome sequencing and bulked segregant analysis.
Toward Fusarium-Resistant Commercial Bananas
Dr. Chen said the findings will support the development of commercial banana varieties that can withstand Fusarium wilt.
“While Calcutta 4 provides crucial genetic resistance, it isn’t suitable as a commercial cultivar because it doesn’t produce fruit which are good to eat,” he said.
The next phase of research focuses on turning this genetic insight into practical breeding tools.
“The next step is to develop molecular markers to track the resistance trait efficiently so plant breeders can screen seedlings early and accurately before any disease symptoms appear.
“This will speed up selection, reduce costs and hopefully ultimately lead to a banana that is good to eat, easy to farm and naturally protected from Fusarium wilt through its genetics.”
STR4 affects banana crops in subtropical regions worldwide. It is a genetic variant of Tropical Race 4 (TR4) which is found in Australia.
The study was funded by Hort Innovation through banana industry levy funds and contributions from the Australian Government. The results are expected to guide future investments aimed at turning these genetic discoveries into practical tools for banana breeding and wider industry adoption.
The findings are published in Horticulture Research.
