Wetenschap - 13 november 2010

Proteins for fertilization also help pathogens invade plant tissues

Plant breeders risk making their crops more susceptible to fungal diseases in their attempts to improve seed fertilization. This is stated by phytopathologist Francne Govers in Science.

Govers and her colleague Gerco Angenent wrote in Science on 12 November about 'Fertility Goddesses as Trojan Horses': proteins in plants needed in fertilization also promote fungal infection. Her conclusion is based on research carried out by geneticist Sharon Kessler and colleagues on the model plant Arabidopsis. 'Pollen tubes which penetrate into the pistil of a plant to deliver seed cells are very similar to the tubes of fungal spores', says Govers. 'The protein in the plant which regulates the incoming seed cells is closely related to the protein responsible for susceptibility to barley powdery mildew.'
Mildew is a very hard to fight fungal disease which deposits white or grey fluffy moulds on the plant. Many plants are susceptible to powdery mildew, which causes a lot of damage in grain cultivation. 'Breeders who want to develop resistance against mildew in grain have to realize that fertilization will be affected', says the phytopathologist.
More examples of moulds infecting a plant via the flower can be given, she says. Breeders are not aware of the infection in the initial stages until fruit-bearing begins. That was how the fungal disease ergot in grain took hold of Europe in the Middle Ages. 'People died or suffered from hallucinations after eating bread made from infected grain. A cucumber which rots in the refrigerator has also been infected by a mould which enters via the stigma of the flower.'