Abstract
In general, growth of axillary meristem is inhibited when the apical bud is present. Although this phenomenon, called apical dominance, has been known for long time, the exact mechanism is poorly understood. We are studying the apical dominance of rice. We observed that excision of the apical bud stimulated the growth of axillary tillers, suggesting that the apical dominance works in rice.
Loss of function mutants of D3, D10 genes of rice show striking increase of tillers. We have shown that D10 is an ortholog of Arabidopsis MAX4, which is implicated in the synthesis of SMS (Beveridge 2006). In d10 mutants, growth of tillers are not suppressed even in the presence of the apical bud, and the application of auxin induce transcription of D10. Base on these results, we will discuss the possibility that D10 and SMS act as second messengers of the auxin in the apical dominance.
