MAX4andRMS1are orthologous dioxygenase-like genes that regulate shoot branching inArabidopsisand pea

Abstract

Shoot branching is inhibited by auxin transported down the stem from the shoot apex. Auxin does not accumulate in inhibited buds and so must act indirectly. We show that mutations in theMAX4gene ofArabidopsisresult in increased and auxin-resistant bud growth. Increased branching inmax4shoots is restored to wild type by grafting to wild-type rootstocks, suggesting thatMAX4is required to produce a mobile branch-inhibiting signal, acting downstream of auxin. A similar role has been proposed for the pea gene,RMS1. Accordingly,MAX4andRMS1were found to encode orthologous, auxin-inducible members of the polyene dioxygenase family.