Surveys of microbe populations on plants have stuck mainly to leaves, but research now shows that flowers of apple trees (pictured) harbour a diverse and changing population of microbes.
Jo Handelsman at Yale University in New Haven, Connecticut, and her colleagues sequenced the DNA of microbes residing on the flowers of six apple trees at five points in their flowering cycle. In total, the authors identified 1,677 types of bacterium and archaeon.
From buds to petal-fall, six microbial groups colonized and dominated in succession. Although prevalent taxa produced the successional pattern, transient and rare taxa were behind tree-to-tree variation.
The team also found that the antibiotic streptomycin — which is used to control blight on commercial apple farms — lowers diversity, but does not affect the sequence of succession.