Author contributions
Hendrik Swiegers, Barbara Karpinska and Yan Hu undertook all the
experimental work. Hendrik Swiegers analysed all the data and prepared
the figures for the manuscript. Ian Dodd oversaw the studies on
phytohormones and helped to prepare the manuscript. Anna-Maria Botha
co-supervised Hendrik Swiegers, discussed the data and helped to prepare
the manuscript. Christine Foyer designed the studies, discussed the data
and wrote the manuscript.