Differential Expression Analysis And Cytological Observations On Pollen Abortion Of Two Newly Elected Maize Male Sterile Line

Cytoplasmic male sterility is a very important type of male sterility,its exploration of the molecular mechanism and abortion has become an important part of the corn breeding research. T-type CMS line of the corn by Bipolar is Maytides T race a high degree of post-secondary infection;S-type CMS line is the gametophyte sterility,more environmentally sensitive, unstable fertility, poor availability on the production. Therefore, the utilization of C-type CMS lines for corn breeding is of great significance.In2003,Maize Research Institute Of Sichuan Agricultural University with cyanobacterium-mediated technique make Bt gene introduced breeding excellent inbred lines receptor18-599(red), find a lot of male sterility plant Al, A2in the regenerated T2generation plants.So, In this experiment, two copies male sterility of new materials Al, A2, and the corresponding maintainer lines18-599(red) as the test material,By the paraffin section,HPLC and cDNA-SRAP study difference on sterile materials and maintainer lines from the cells of morphology, epigenetic and molecular level.The results of the experimental are as follows:1.Through the observation of paraffin section of the development process of anther infertility materials found tapetum have changed in two ways.The first abortion method is found in the tetrad stage the tapetal cells of sterile anthers vacuolization and slight radial enlargement gradually inward to shrink out of anther wall.The second abortion that is the earlier occurrence of the disintegration of the pollen mother cells, it showed signs of concentrated disintegration in the early subtrahend first division.during this period tapetal cells appeared abnormal, rapid vacuolization of its cells and sharp increase in radial thickness,most of the chamber room is occupied by tapetum cell that enlargement rapidly,only some vestiges of disintegration of the pollen mother cells were left.The first abortion in the two kinds of sterile materials Al, A2, are found,the second abortion should be only found in the A2male sterile and in the different anther cells in the same anther of sterile materials A2appeared in two different ways of abortion.2.By high performance liquid chromatography to analyzed the level of genome DNA methylation of the blade in the different growth periods and tassel in the meiosis, a tetrad period, monocyte period and dual-core of sterile materials. It can be obtained:In some sterile materials,the DNA methylation level of blade’s Genomic in the vegetative stage did not change basically, maintained at the same level; and the DNA methylation level of blade’s Genomic of maintainer lines is very higher in the jointing stage than the seedling stage,the trend of changed about genomic DNA methylation level of the ear in the four development period of sterile materials and maintainer lines is different, in maintainer lines its DNA methylation levels in the four periods are has been rising and in the dual-core period reached the highest,but the DNA methylation levels of the sterile materials appeared is increase at first reduce tendency and in a tetrad period was the highest,the two infertility materials show the same trend.3.It was used SRAP to studied differentially expressed genes in the maize male sterile material and fertile material anthers at different developmental stages, there are4pairs of88primer combinations could specific amplification in the material of infertility,four pairs of primers were me3×em2,me4×em2,me6×em2,me7×em2,the four pairs of primers in the amplification effect of the different periods of the same material is the same.Four specific fragments found in the sterile material A1,temporarily named me3-A1, me4-A1, me6-A1, me7-A1;four specific fragments found in the sterile material A2,temporarily namedme3-A2, me4-A2,me6-A2,me7-A2.By sequence analysis shows that the segment and the maize mitochondrial genome atp4gene similarity is higher.So infer that the segment is related with cytoplasmic male sterility.In this study, with cDNA sequence of two male sterile to analyzed the homology, and found two male sterile cDNA sequence had a certain similarity.