Fine Mapping And Expression Of The Red Plant Mutation Re Gene In Upland Cotton

In cotton, researches about the leaf color gene have been reported. Genetic mapping leaf color mutant genes is helpful to promote the application of the molecular marker assisted selection in agriculture, at the same time, can lay a foundation for map-based cloning of this gene.In this research, we found the red plant mutation, designated it as Re temporarily, from the process of backcross of the Gossypium hirsutum cv. Emian22（E22） and G. barbadense acc. 3-79. We constructed a F2 segregation population using two parents E22 and BC1S9. In the segregation population, three phenotypes appeared including the red plant, the intermediate type and the green plant; also the segregation ratio fit Mendelian 1:2:1 inheritance. We conducted fine mapping and expression analysis using F2 recessive population containing 1898 plants. The main results were as follows:1. In F2 population, we selected 10 plants to build red plant bulks and 10 plants to build green plant bulks. Based on the high-density G. hirsutum × G. barbadense genetic linkage map in our lab, the marker MON_DC40065 was identified to be linked with Re. Then we developed 470 SSRs and 126 primer pairs based on UTR of the gene using D5 genome of G. raimondii as the reference genome, and 80 SSRs using the genome sequence of G. hirsutum. These markers were screened for polymorphism using the BSA method. Linkage analysis showed 11 markers were linked with Re. Re was located between C hr01₈M-004 and Gr01₉-13M₀56 on chromosome D07, and the physical distance of two markers was about 1.5 Mb.2. There are 88 genes within the target area. Through KEGG database analysis, five gene are associated with the process of pigment synthesis and transport, including RE1、RE2、RE3、RE4、RE5. Expression analysis of the genes within the target area between two parents E22 and BC1S11 were conducted, nevertheless, only relative expression levels of RE3 showed significant differences between the two parents. This gene has been confirmed associated with the transport of anthocyanins in other plants.3. Except fine mapping the red plant muta tion, the backcross populations were constructed. Genetic background selection of the individuals of the backcross plants showed that two individuals similar to E22 most as recipient parent were selected from the BC5S2 and BC7S2. It laid a foundation for the construction of the Near Isogenic Lines and screening the recombinant individuals.