Preliminary Study On The Relationship Between Mitochondrial VDAC And Maize C-type CMS

Cytoplasmic male sterile plays an important role in heterosis utility.As an important compoment, mitochondron is considered to be related to CMS in many plants.Mitochondria is subject to a series of signal transduction pathways control, involved in energy and substante metabolism process and mitochondria-mediated apoptosis. When something is wrong with physiological function of mitochondrial, some abnormal phenomenon may be grown, such as cytoplasmic male sterility. Mtiochondrial membrane permeability is part of an important manifestation of mitochondrial function. As an major compoment of the mitochondrial outer membrane, VDAC expression abnomal could affect membrane premeability directly. In this study the C48-2and N48-2and F1(C48-2×18-599white) were used as material for the mitochondrial membrance permeability test and quanititative PCR analysis with VDACla and VDAClb gene. In order to understand the relationship among VDAC1a and VDAC1b expressiond,mitochondrial membrane permeability, along with the CMS phenomon. The main results obtain in this study as follows:1. Analysis for mitochondrial membrane permeability physiological index. The variation tendency of MDA content in the tassel of male sterile line C48-2were low at pollen mother cell phase, then elevate to high level for tetrad phase, mononuclear phase till to binucleate phase. The maintenance line N48-2and the fertile F1showed a contrary trend to the C48-2. Mitochondrial membrane absorbance for the three materials were more higher in seeding than that in tassel of different development stages. As for the tassel, it was relatively constant not only among the different materials but also among the same material during different development stage. The Cyt c/a value for N48-2and the fertile F1not only in the seedling but also during anther’s different development stage show no obvious difference. Cyt c/a value for C48-2in the seedling and pollen mother cell and tetrad phase were consistent with fertile materials, but it became obvious lower for the mononuclear phase and binucleate phase in C48-2. The Ca2+content for N48-2and the fertile F1during pollen development period were almost the same. The Ca2+content of C48-2did not show obvious difference between pollen mother cell stage and tetrad stage. However, the Ca2+content of C48-2for mononuclear phase and binucleate phase showed a obvious decrease. The analysis for fluorescence intensity of mitochondrion showed fertile F1were higher than the N48-2and C48-2. The fluorescence intensity for male sterile line was obviously reduced at mononuclear phase and binucleate phase compared to N48-2, but at the pollen mother cell phase and tetrad phase, the fluorescence intensity for C48-2and N48-2were almost the same.2、Fluorescent quantitative PCR for VDACla and VDAClb. VDACla gene had a relative higher expression level in mononuclear phase and binucleate phase than that in pollen mother cell phase and tetrad phase for C48-2. But the expression trend for N48-2is just opposite to C48-2. The expression of VDAC1b gene is higher in mononuclear phase than that in the binucleate phase, both of them higher than that of pollen mother cell phase and tetrad phase for C48-2.The trend of the relative expression of the VDAC1a and VDAC1b are consistent. To some extent, it is in accordance with the main abortion period of CMS-C.In summary, combining the results of mitochondrial membrane permeability related physiological index with the Fluorescent quantitative PCR for VDAC1a and VDAC1b, it was suggested that mononuclear phase is a critical phase for maize CMS-C. VDAC1a and VDAC1b could be related to the male sterility by affecting the mitochondrial membrane permeability.