Path of Panama disease fungus established for the first time
Panama disease is a form of Fusarium wilt, caused by Fusarium oxysporum. The strain of this fungus known as Tropical Race 4 (TR4) affects many local banana varieties as well as the Cavendish cultivar, which accounts for 85% of world trade in bananas. Since all Cavendish bananas are clones of each other and there is little variation, they are highly susceptible to TR4, making the sector extremely vulnerable.
As explained on phys.org, the fungus, which appeared several decades ago, infects the roots, attacks the vascular system and eventually kills the plant. Once a plot is infected, bananas can no longer be cultivated there. This is a major threat to the global monoculture of Cavendish bananas.
TR4 has now been detected in Myanmar for the first time and its presence in Vietnam and Laos has been confirmed. In addition, research has made it possible to see which path it took to get there. There are links between the strains found in TR4 in China and these countries and in Pakistan and the Philippines, and between those detected in Lebanon and Jordan.
After sampling missions, the fungus was isolated from infected plants and then further studied by means of DNA testing. By determining the number and nature of mutations in the fungus, scientists were able to see exactly which strains are related. "This has reaffirmed the need for quarantine measures to prevent international spread and the need for sustainable solutions," states Gert Kema, professor by special appointment of tropical phytopathology at Wageningen University & Research.
