Primary Mapping And Physiological Characterization Of Chinese Cabbage Dwarf Mutant Cd1

Cabbage is a native vegetable in China with a long history of cultivation.The Latin name is Brassica pekinensis(lour)Rupr.It belongs to the Brassicaceae Brassica genus and is a biennial herbaceous plant.It is one of the vegetables widely cultivated and eaten throughout China.In this experiment,the dwarf mutant cd1 and wild type in the constructed EMS mutagenesis mutant library were used as the test materials.The phenotypic and physiological indicators were identified,cytological identification,and exogenous hormone treatment were used.And pollen viability identification,etc.,and then preliminary location of cd1,identification of candidate genes,and expression analysis,the main results are as follows:1.The cd1 phenotype and pollen viability identification analysis of cabbage dwarf mutant showed that the mutant cd1 plant was significantly dwarfed.Compared with the wild type,cd1 grew slowly,the hypocotyl was extremely short,and the leaves were darker,bristly and accompanied It has leaf fissure traits,narrower leaf area,prominent leaf veins,root elongation is significantly suppressed,the number of lateral roots is significantly reduced,and the total number of roots is also significantly reduced.When the mutant cd1 was bolted and flowered,we found that the stamens in cd1’s petals had significantly less pollen.The results of magenta acetate staining showed that no viable pollen grains were found in cd1,indicating that the pollen was not viable.2.The physiological index identification results found that the mutant cd1 chlorophyll a,chlorophyll b,and total chlorophyll content were higher than the wild type,because the chlorophyll content was higher,which led to the mutant cdl photosynthetic rate,intercellular CO2 concentration,stomata The transmissivity is also higher than that of the wild type.It can be explained that the darker color is helpful for photosynthesis.Since the transpiration rate is lower than that of the wild type,the mutant cd1 has a stronger adaptability to the external environment.3.The cytological identification results showed that the number of cells was significantly reduced and the arrangement was irregular when the leaves were observed.Therefore,it is speculated that the difference in leaf phenotype is due to the decrease in the number of cells and the irregular arrangement of cells.Observing the stem,it was found that the parenchymal cells and the pillar cells in the stem tissue failed to extend normally in the longitudinal direction,which indicated that the cd1 main stem cell division process was inhibited,resulting in a decrease in the number of cells.As a result,the stems become shorter.4.The results of exogenous gibberellin spraying showed that the dwarf mutant cd1 with gibberellin was exogenously restored in plant height.Other traits such as leaves were absent in leaf length,leaf width,and leaf undulation.obvious change.Therefore,the dwarf mutant cd1 has certain sensitivity to the treatment of gibberellin exogenous hormones,and it is speculated that the reason why the mutant cd1 strain becomes shorter due to a deficiency in hormone synthesis.5.Determine the position of the target gene by verifying and analyzing the results of BSR-Sep.Then through the Chinese cabbage 3.0 database and the Primer5 software,the primer SSR design was developed to effectively select primers with certain polymorphisms and related mutant cd1 genes and complete the corresponding linkage markers,so as to finally confirm the dwarf mutant cd1 gene Is located between primers L06-09 and L06-14(physical position 21621766-24683923).6.This study performed differential expression analysis on its candidate genes,and finally identified two candidate bases: Br A06g034110.3C,and Br A06g033010.3C.These two candidate genes will be further verified in subsequent fine mapping.