| Non-heading Chinese cabbages(Brassica campestris ssp.chinensis)is an important vegetable crop genus Brassica of Cruciferae family and is widely cultivated in China.The shape of leaves are rich and varied,including different types of lobular,narrow leaves and lobed leaf,while lobed leaf is a novel mutant.The leaf-lobed mutant not only enriched the germplasm resources of cruciferous crop,but also the ideal material to explore the genetic development and physiological function.In preliminary study,we have mapping the leaf-lobed gene BrcLL of non-heading Chinese cabbage in 1.8 cM,and found it was regulation by a new gene.But in preliminary study,we have small population,less molecular marker and the positioning range of gene BrcLL is larger.And we have not study the relationships between leaf-lobed mutant and physiological characteristics of stress-resistance.In this study,we use a near isogenic line with their smooth margin phenotype line 13XS198B and leaf-lobed phenotype line 13XS199H as experimental materials,to observation analysis their morphological and physiological characteristics.Using the near-isogenic line segregating population(F2-11),to fine mapping gene BrcLL,by expand the group numbers of plant and developing the new molecular markers from preliminary mapping range.Finally,to evaluated the potential utilization of linked marker with BrcLL in cruciferous crops.The main results are as follows:1.Using different concentrations of PEG simulated drought environment,analyzed the leaves wilting index,water loss rate,related water content,relatively conductuivity,content of MDA and antioxidant enzymes activity of 13XS198B and 13XS199H.Along with the increase of PEG concentration,the leaves wilting index,water loss rate,the relative conductivity and content of MDA in 13XS198B have increase greater than 13XS199H,relative water content in 13XS198B have decrease greater than 13XS199H.At high concentrations of PEG,the SOD,POD and CAT activity of 13XS199H were higher than 13XS198B.After comprehensive comparison,we preliminary evidence that 13XS199H has greater drought resistant ability.2.Compare the near-isogenic line of 13XS198B and 13XS199H.The results show that,the length,width of the leaf,length,width,thickness and type of the petiole have no significant difference.But the leaf area of 13XS199H was significantly reduced about 60%.And the maximum depth and numbers of lobed leaf were showed significantly increased.And the first branch numberswere also exist significant difference in F2-11B and F2-11H.3.The genetic analysis showed that the total number of three different leaf shape plants(B,F,H)in F2-11 accordance with the ratios of 1:2:1,namely,phenotype trait of leaf-lobed in the group is controlled by an incomplete dominant gene control.4.Using the transcriptome sequencing sequence of near-isogenic line to sequence alignment with the encoding gene sequence in Chinese cabbage,successful developing 9 closely linked marker with BrcLL.The BrcLL locus was delimited between Bra9511 and Bra9512,the genetic distance was 0.07 cM and 0.08 cM,physical distance is 5.7 kb.The positioning interval has no annotation of predicted genes.5.Using 11 linked marker primers with BrcLL in this experiment,to value assessment to 37 cruciferous crops.Results showed that 11 primers in Brassica rapa and Raphanus sativus have different expansion rate,and Brassica rapa with 91.6%have higher expansion rate than Raphanus sativus with 36.4%.After clustering analysis,11 primers can differentiate cruciferous crops from different species.It showed that these SNPs,SSRs and InDels had good transferability among species of cabbage. |
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