A Novel Mode of Interactions Between Two Sterility-related Mitochondrial Genes and Two Restorer Genes in HL-CMS Rice

As a new source of germplasm in rice, the Honglian gametophytic cytoplasmic male sterility (HL-CMS) has been demonstrated to have great potential for hybrid rice production and theoretical studies. In the rice HL-CMS/Rf system，the two sterility-related mitrochondrial genes (orf216 and orfH79) and two restoring genes (Rf5 and Rf6) being detected, make it difficulty to study the mechanism of their nucleo-cytoplasmic interaction. In our project, through screening a great deal rice germplasm using orf216 and orfH79 as the markers, the isonuclear alloplasmic male sterile lines, L-orf216 and L-orfH79 carrying orf216 and orfH79 respectively, were created. And through the cross of YTA//YTA/9311, the near-isogenic restorer lines, L-Rf5, L-Rf6 and L-Rf5-6, were established. The expression model of the sterility genes and restorer genes in the offsprings from the crosses between different isonuclear alloplasmic male sterile lines and near-isogenic restorer lines were then studied through RT-PCR, qRT-PCR, Northern blotting as well as pollen fertility testing. And the interactions betwenn the expression products of the 2 sterility genes and the 2 restorer genes were further studied with Western blotting and gel blocking method. Based on the results, a novel mode of interactions between two sterility-related mitochondrial genes and two restorer genes in HL-CMS rice was proposed.