Inheritance Of Mosaic-leaf Trait In Brassica Napus And Its Gene Mapping

Mosaic-leaf is one of leaf traits in Brassica napus. Its applications are reflected in the field such as hybrid identification, purity test and genetic studies, etc. The previous genetic studies on mosaic-leaf trait in Brassica napus showed that it's controlled by one to two pairs of quality genes, and its genetic characteristics is relatively simple. However, no gene mapping study on this trait has been reported yet.This research took the F2 segregation populations of combination I (No.2127-17/Huaye) and combination II (YZ001-6/G350) which are constructed by four varieties (strains) of Brassica napus as materials. Applying Bulked Segregant Analysis (BSA) method and Simple Sequence Repeats (SSR) marker technology, we screened out the SSR makers correlated with the mosaic-leaf gene to analyze genotypes of the mapping population, and then drew genetic linkage maps. In addition, we do comparison study on the colinearity of SSR markers between two genetic maps and then do a bioinformatics analysis to the position area. The main results are as follows:1. That the leaf morphology of Fl plants revealed semi-mosaic-leaf phenotype suggests that mosaic-leaf is a partial dominant trait.2. Genetic analysis results indicate that leaf morphology is controled by one pair of major genes, which is designated as BnML (Mosaic-leaf in Brassica napus).3. The genetic linkage map in combination I shows that the BnML is located in the area between two molecular markers namely BrGMS3707 and SSR648, whose genetic mapping distances are 16.2cM and 8.3 cM respectively; While the genetic linkage map combination II targeted BnML gene in the area between two molecular markers namely BrGMS4768 and BrGMS4779, whose genetic mapping distances are 4cM and 6cM respectively.4. Take advantage of the existing colinearity of molecular markers BrGMS3705 and SSR648 between genetic maps of two combination, we finally locate the mosaic-leaf gene BnML on chromosome A10 of Brassica napus, to say precisely, it's located in the range of 10 centimorgan distance between molecular markers BrGMS4768 and BrGMS4779, which lay a foundation on fine mapping and cloning of the BnML gene.5. Through comparative analysis between molecular marker and genome sequence of Brassica rapa, we further match the targeted area to 975-kilobase range in physical map drawn by splicing sequence of Brassica rapa. In this area, we predicted that four candidate sequences which are highly relevant to the gene family regulating leaf morphology in Arabidopsis thaliana through highly conservative protein structure domain search, which provides beneficial enlightenment for follow-up study.