| Leaf bristle traits are a form of leaf trichomes,which are widely found in plants.There are different forms of trichomes in cucumber,pepper,Arabidopsis,mustard and other plants.The growth of trichomes is diverse and their functions are different.Leaf trichomes can improve the herbicide resistance,insect resistance,and stress resistance of plants.Leaf trichome traits can also be used as indicators for some traits in marker selection assisted breeding.Little research has been done on the leaf trichome traits of Chinese cabbage(Brassica rapa pekinensis)There are two cases of blade trihcomes: blade edge trihcomes and leaf surface trihcomes.Among them,leaf trihcomes are rare.And the trihcomes on the leaf edge often accompany the burrs on the leaf surface.In this experiment,the double haploid line of Chinese cabbage(DH line)was used as the experimental material,and the method of EMS mutation and seed germination was used to create mutants with multiple mutation phenotypes.The leaf truncated,genetically stable mutant trm was used to identify the mutant traits and locate the mutant gene.The results as follows:1.The wild type 'FT' and the mutant trm were crossed,backcrossed,and selfed to obtain offspring and the representative type after observation.According to the analysis of the six generation phenotypes and the separation ratio,it is obtained that the offspring are all wild phenotypes,all the offspring backcrossed with the wild-type parents are wild phenotypes,and the wild phenotypes and mutant phenotypes of the backcrossed offspring with the mutant parents appear 1 : 1 separation ratio,phenotype conforms to 3: 1 separation ratio,which proves that the foliar traits of the mutant trm belong to recessive inheritance of single nuclear genes.2.The mutant plant trm was crossed with cabbage cultivar '701' to obtain,and selfed to obtain segregated population.50 mutant phenotype and wild phenotype plants were selected from to establish two extreme pools.RNA sequencing was performed on the two mixed pools,using BSR-Seq technology,referring to the Chinese cabbage database version 2.5,and the mutation site was located in the 2,034,489 bp length segment on the A06 chromosome.Further developed of SSR markers and In Del markers for fine mapping,and finally positioning the mutation site between marker I31 and marker I38,the genetic distances of two markers were 0.12 c M and 0.20 c M,and the physical distance between the two markers was 82.9 Kb(Zhao Yonghui,2019).There were 13 genes in this interval.3.By re-sequencing the DNA of the wild-type 'FT' and mutant trm,the candidate gene Brtrm was selected.The mutation occurred on the 10 th exon of the Bra A06g043560.3C gene,and the 2120 th base was composed of guanine(G)mutation to Adenine(A)causes the amino acid at position 707 to be changed from Alanine to Valine,resulting in the addition of a benzene ring to the protein structure and changes in function.The mutant gene is homologous to the AT5G43810 gene in Arabidopsis.In Arabidopsis,this gene regulates the expression of AGO10 protein.AGO10 protein can control the occurrence of meristem stem cells by down-regulating ARF2-mediated auxin;it can also inhibit the regeneration of buds in vitro by inhibiting mi R165 / 166. |
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