From the story in Nature News:
“The plant appears alive, but it’s only there for the good of the pathogen,” says plant pathologist Saskia Hogenhout from the John Innes Centre in Norwich, UK. “In an evolutionary sense, the plant is dead and will not produce offspring.”
“Many might baulk at the concept of a zombie plant because the idea of plants behaving is strange,” says David Hughes, a parasitologist at Pennsylvania State University in University Park. “But they do, and since they do, why wouldn't parasites have evolved to take over their behaviour, as they do for ants and crickets?”"
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