Genetic Mapping Of Ga1-S And Its Mechanism Of Cross-Incompatibility In Maize

Gametophyte genes affect the sexual transmission of haploid gametes in maize. Ga1-S derived from pop-corn, is one of the most thorough one-way cross-incompatibile genes. It is a unique mutant to study gene interaction in the process of fertilization and signal transduction and mechanism of incompatibility. Corns of ga1-s/ga1-s genotype pollinated by corns with Ga1-S/Ga1-S can produce full sets of seeds; the reciprical cross, however, can not. Using the Ga1-S gene can prevent transgene contamination between transgenic and traditional corns. The objectives of this study are to 1) fine map Ga1-S gene and 2) study its mechanism of gene action using w22 and w119/Ga1-S maize isogenic lines, The main results are as follows:1)Heterologous pollen tube elongating obstruction into Ga1-S caused hybrid incompatibility except for in W119 / Ga1-S (GG), but the style can germination in the style of pollen tube elongation is restrained, make the pollen tube growth slow finally stop growing.2)Two hours after pollination in the different materials , maize pollen tube of W119 / Ga1-S (GG) grow slower than others because of the expression of Ga gene, while W119 / Ga1-S (GG) pollen tube grown in W119 / Ga1-S (GG) elongation increased rapidly.3)In this study, we identificated the time and position of the pollen tube of different materials. 23 hours after pollination , pollen tube of fertile reached ovary , but sterile stop elongation at about 17% from the top .4)We used 136 SSR markers for polymorphism screening . Ga-S gene was mapped with F1BC1 populations between umc1682 and umc1294 , and genetic distance of about 20 cM.