Arabidopsis ENHANCER OF SHOOT REGENERATION 2 and PINOID are involved in in vitro shoot regeneration

ENHANCER OF SHOOT REGENERATION 2 (ESR2), like ESR1, plays several critical roles during in vitro shoot regeneration. We investigated the genetic interaction between ESR2 and PINOID (PID) during shoot regeneration in this study. Both esr2 and pid mutations markedly decreased the efficiency of shoot regeneration from root segments at comparable levels (27% and 35% of shoot numbers on wild type, respectively); while esr2-2 pid double mutants dramatically decreased the efficiency of shoot regeneration (4.7% of shoot numbers on wild type). Our results demonstrated an additive or synergistic effect of these two mutations on shoot regeneration. Expression of ESR2 in pid explants during shoot regeneration was abnormal after day 5, although pid mutation did not affect ESR2 expression until day 5. In conclusion, PID appears to be required for late development of the shoot apical meristem during shoot regeneration.