Abstract
Rice has the canonical α(Gα), β(Gβ) and γ(Gγ) subunits, which mammals have. The deficient mutant for Gα gene, d1 exhibits dwarfism compared with WT. Previously we showed that the dwarfism in d1 was due to reduction in cell number. When we compared the responses of 7 plant hormones between WT and d1, the d1 mutant showed less sensitivity to brassinolide (24-epi BL). This result showed that a brassinosteriod (BR) signaling may be partially impaired in d1. In order to investigate relationship between the G protein signaling and the BR signaling, we analyzed a double mutant of d1-1 and d61-2 which was a deficient mutant of BR receptor kinase gene (OsBRI1).
Organ length of leaf sheath was synergistically reduced in d1-1d61-2 compared to d1-1 and d61-2. However, cell number of leaf sheath in d1-1d61-2 was not different from that in d1-1. This result suggests that d1-1 may be epistatic to d61-2 in regard to the regulation of cell number. We are carrying out the analysis whether the epistsis is observed in internode and lemma.
