NDC80 and Infertility: A number of observations suggested that HEC genes could also be involved in mediating auxin signalling during gynoecium development: First, hec1,2,3 mutants showed enlarged petals and complete infertility (Fig. 3A,B; supplementary material Fig. S2) (Gremski et al., 2007), traits which have been linked to defects in the regulation of auxin transport, signalling, or synthesis in numerous studies (Cheng et al., 2006; Okada et al., 1991; Varaud et al., 2011).