Knockout of eight hydroxyproline-O-galactosyltransferases cause multiple vegetative and reproductive growth defects

•Eight Hyp-GALT genes are known to add galactose to arabinogalactan-protein cores.•Mutation of eight Hyp-GALTs interrupts both vegetative and reproductive organ growth.•Distorted pollen cell wall structures make them to collapse.•Semi-sterile anthers and short filaments leads to extremely low seed-set.