Mechanism Of Nuclear Male Sterility In G17AB Line Watermelon

To discover the mechanism of nuclear male sterility in G17AB line watermelon, a serious of studies, included heredity, physiological and biochemical Characteristics, molecular markers, DDRT-PCR, and so on, were carried out. The results were listed as follows:1 The Comparisons Of Agronomic Characters And Genetic Analysis In Male Sterile G17AB Line WatermelonThe comparisons of agronomic characters were made between male sterile plants and male fertile plants. The results showed that the only difference was on the male organs, the anthers of sterile male organs were smaller and couldn't produce pollens. Genetic analysis indicated that sterility in G17AB line watermelon was controlled by a pare of recessive nuclear genes.2 The cytological and histochemical study on anthers of male sterility in watermelon G17AB LineThe cytological study on watermelom male sterility G17AB line showed that the abortion occurred before the formation of microspore tetrads. Microspore mother cells were of abnormal meiosis, disagragated after a few nucleoli appeared, and failed to develop into pollens. The tapetal cells developed abnormally. At late stage of abortion, the cells of anther wall disaggregated and locules collapsed. Histochemical observation indicated polysaccharide and soluble protein in male sterile anther were lower than that in male fertile anther.3 The Ultra-structure of Anther in The Male Sterile Watermelon G17AB LineThe ultra-structures of anthers in G17AB line watermelon were observed under transmitting electron microscope. The main results were list as follows: The differentiation of anther wall in Male sterile anthers was abnormal. Abnormal tapetum cells were smaller in size and fewer cell-organelles. With anther development, Cytoplasm of the abnormal tapetum cells was pressed to the cell membrane and then degenerated. In meiosis, many vacuoles were formed in microspore mother cell, it resulted in abnormality of cell-organelles, then cytoplasm shrinked and degenerated. On the basis of all feature observed, the reason for male sterility in watermelon G17AB were discussed.4 Analysis on the Physiological and Biochemical Characteristics Of Nuclear MaleSterile Line In WatermelonThe physiological and biochemical indexes were compared between male flower buds and fertile male flower buds in recessive nuclear male sterile G17AB linewatermelon. The results showed that in male sterile buds, the contents of reductive sugar, starch, soluble proteins, IAA, GAs, and polymines were lower, while ZRs was richer, and the peak value of ABA appeared earlier; the activities of Peroxidase isozyme were stronger, but one specific cytochrome oxidase tape was obviously lack during all developmental stages, a specific soluble protein tapes with SDS-PAGE was lack in the early developmental stages.5 The Optimization of RAPD-PCR System and Molecular Marker Of Male Fertile Gene in Watermelon G17AB LineThe optimal RAPD-PCR system in watermelon was established with orthogonal design, and one of RAPD markers linked with male fertile gene in watermelon G17AB line was selected with the optimal RAPD-PCR system. The specific DNA fragment is about 3.0k bp. The heredity distance between the marker and the male fertile gene is about 8.1cM.6 AFLP Markers And Sequence Analysis In Watermelon Genic Male Sterile LineAFLP analysis in watermelon nulear male sterile G17AB line was carried out with 64 pairs of amplification primer combinations, and two primer combinations showed polymorphism between fertile genome DNA pool and male genome DNA pool. Southern dot blotting analysis proved that only F₃/3 AFLP fragment, amplified with E-ACA and M-CAG, was positive in fertile genome DNA as template. Through recovery from denatured polyacrylamide gel and cloned to pMD18-T vector. Sequence analysis showed F3/3 AFLP fragment is of 74% of homologous with an code sequence of an unknown protein in Arabidopsis thaliana.7 mRNA differential display of male flower buds in male sterile G17AB line of watermelonmRNA differential display was used to analyze the differential express...