Toxic substances in banana plants kill root pests

Bananas are a major food staple for about 400 million people in the tropical and subtropical regions of Asia, Africa and Latin America. However, banana yields worldwide are severely threatened by pests.

Dirk Hölscher from the Max Planck Institute for Chemical Ecology in Jena, Germany, and an international team of researchers have discovered that some banana varieties accumulate specific plant toxins in the immediate vicinity of root tissue that has been attacked by the parasitic nematode Radopholus similis. This local accumulation is crucial for the plant's resistance to this pest organism. The toxin is stored in lipid droplets in the body of the nematode and the parasite finally dies. These findings provide important clues for the development of pest-resistant banana varieties.

Bananas are among the world's most important food crops. Dessert bananas are produced primarily for homegrown consumption in China and India and for export to the northern hemisphere in Latin America. In Europe, they represent the most popular tropical fruit. Plantains (a type of cooking banana) are important components of daily meals in Africa and Southeast Asia. They are highly prized because of their high contents of nutrients, such as potassium, magnesium and vitamins B and C.

Apart from fungi and insects, the parasitic nematode Radopholus similis is considered a major banana pest. It attacks the roots of banana plants, causing slower growth and development of the plant and fruit. In the final stage of the disease plants topple over ? often when already bearing an immature fruit bunch. Yield losses up to 75% can be the result of R. similis infestation.