Fine Mapping And Candidate Gene Analysis Of Brtri1, A Gene Controlling Trichome Development In Chinese Cabbage

Chinese Cabbage(Brassica rapa L. ssp. Pekinensis) is widely cultivated in China with the highest yield and largest planting area. Trichome is the derivative structure over the skin of the plant, and it is the ideal systems for studying plant cell differentiation. In this paper, by using a glabrous Chinese cabbage DH lines’FT’and DH line’PurDH-1’with Trichomes to construct segregating population, and a gene controling trichome development in Chinese cabbage was been cloned.1.Using ’FT’ and ’PurDH-1’, the F2 segregating population was constructand containing 5027 individuals, in which 3801 plants have Trichome and 1226 plants exhibit glabrous. That indicated that a single dominant gene control trichome development in Chinese cabbage, designated as Brtril.2. With 1226 plants without trichomes in F2 segregation population as mapping population, eventually Brtril was localized chromosome A06 between molecular marker pur6-31 and pur6-39, with the physical distance of 16.84 kb. Gene prediction show that the region have four complete ORF, in which Bra025311 is highly homologous with Trichome regulate genes GL1 in Arabidopsis, encoding a MYB transcription factor. Therefore, BraO25311 was as the candidate gene of the Brtril.3.Sequence analysis showed that there is a deletion of 5bp in third exon in ’FT’, which result in the shift mutation in Bra0253114.Expression pattern analysis showed that Bra025311 normally expressed in’PurDH-1’ but not expressed in’FT’.5.Based on the sequence difference of the third exon, one codominant Indel markers were developed, which can effectively distinguish the heterozygous genotype and homozygous genotype, and can be used for the marker assisted selection of the non surface coat traits.