Genes that make lemons sour revealed

Dutch scientists have unravelled the mystery of why some citrus fruits are eye-wateringly sour and others are scrumptiously sweet.¹ The discovery that a mutation in a proton pumping protein can produce sweeter fruit may allow farmers to tune their harvest to customers’ tastes.

The researchers, led by Ronald Koes and Francesca Quattrocchio at the University of Amsterdam, became interest in this area during an effort to identify the genes responsible for the colour of petunia flowers. They looked for differences in two variants of this flowering plant – the standard one with red–purple petals and a blue mutant. ‘The measurements of the crude extract of the petals showed that the blue flowers are less acidified than the reddish ones,’ says Quattrocchio.