Fine Mapping And Molecular Marker Development For Anthocyanin Absent

Tomato, a self-pollination crop, has obvious heterosis. Now in tomato seeds production, hand emasculation and pollination are often used to produce hybrid seeds. In this way, it takes a lot of time and money and it is also difficult to ensure the purity of hybrids. The use of male sterility and seedling character markers plays an important role in lowering the cost and improving the purity of hybrid seeds. ms-10 male sterile materials are widely used in tomato hybrid breeding. On the one hand, it is because that ms-10 mutant can not produce pollen and it is completely sterile. On the other hand, ms-10 is closely linked with aa(anthocyanin absent) gene. And aa mutant plants show green stem result of anthocyanin absent. As a result, ms-10 male-sterile plants can be got in seedling stage by observing the color of the plants which saves more time and cost than traditional selection method. Hence, ms-10 and aa are often used in tomato hybrid breeding at the same time. However, ms-10 and aa are both recessive genes and it is difficult to distinguish the heterozygous plants from the homozygous wide-type plants. Then when ms-10 and aa are translated to other cultivators or breeding material containing ms-10 or aa are chosen, it will take much time by using tradition phenotypic selection method which has low selection effiency. But making use of molecular mark can save breeding time and improve selection effiency. Now, gene MS-10 has been cloned and gene AA is still uncloned. Therefore, in this study the F2 population coming from the crossing of mutant LA312(aa) and wide type LA1589 was used as fine-mapping population and In Del markers which were closely linked with desired gene were developed. Finally, the gene which controls the tomato green stem phenotype was fine-mapped. The main research contents and results are as follows:1. In this research, 140 green stem plants were planted in greenhouse and 126 plants were male sterile. The results indicated that using seedling character marker green stem to choose ms-10 tomato plants has high selection effiency which could reach 90 percent. And this result was in conformity with the previous studies. It indicated that green stem as a seedling character marker to choose ms-10 plants had high selection efficiency.2.Genetic analysis indicated that the aa mutant is controlled by a single recessive gene. Then the gene AA was positioned between markers HP523 and HP527. The physical distance was 96.3kb.3.There are 14 candidate genes in this region. After analyzing the function of every gene in this region, building phylogenetic tree and measuring relative expression of the gene, Solyc02g081340(Sl GSTAA)which encodes a GST was identified as the desirable gene. It was found that there is a 3.4kb deletion in region 45,339,693- 45,343,097(SL2.50ch02) through sequencing. And this deletion leads to the missing of gene Solyc02g081340.4. Molecular marker AAD which was closely linked with the mutant was developed. Taking advantage of this marker can distinguish among homozygous wild type, heterozygous, and homozygous aa mutant genotypes. This marker can be assisted tomato breeding.