The crosstalk between phytochrome B and phytochrome C in rice

Abstract

It has been reported that there is the crosstalk between phytochrome B (phyB) and phytochrome C (phyC) in Arabidopsis. However, we found that the crosstalk between phyB and phyC in rice (Oryza sativa ) is quite different from that in Arabidopsis. In rice phyB mutants, phyC protein levels were greatly reduced in the seedlings grown in the dark, but not in the light. Intriguingly, phyC protein exhibited higher light-labile in WT than in phyB mutants. All these results indicate the involvement of phyB in regulating phyC levels in rice. On the other hand, phyC-mediated responses were not distinguishable in rice phyB-deficiency mutants, suggesting the involvement of phyB in phyC-regulated photomorphorgenesis. To access the molecular mechanisms of crosstalk between phyB and phyC in rice, several transgenic lines were produced and analyzed. Implications of interactions between phyB and phyC on the versatility of plant light sensing and signaling mechanisms will be discussed.