| As one of the world's four major oil crops,rapeseed is widely planted in China and all over the world.With the wide application of crop heterosis,the main large-scale cultivation of rapeseed are cultivated high stalk varieties at the present in our country.It is leading a huge influence on rapeseed production and development because of the easily lodging in them.Therefore,the creation,exploration,studying and using in dwarf and semi dwarf rapeseed play an important role in Genetic Breeding.This research is based on the material of Brassica napusL.The E5041 mutant with dwarfing plant height were raised by treatment of EMS inducement of high ancestorNY18.The major gene and polygene mixed genetic model was used to analyze the P1?P2?F1?and F2 population of rapeseed cross between wild high line NY18 and dwarf mutant line E5041.The effects of exogenous gibberellins(GA3),auxin(IAA)and brassinosteroids(BRs)application on early hypocotyls growth of E5041and NY18,was studied.High-performance liquid chromatography-mass/mass spectrometry was used to determine the contents of endogenous hormones.DGE was used to analysis the differently expressed genes between E5041 and NY18.It could apply to genetic improvement and provide a theoretical reference.The main results were as follows:1.The results of height genetic analysis of E5041 showed that the genetic model of height trait was fitted forMX2-EAED-AD,which was the two pairs of the equal additive major genes plus additive-dominant polygene model.The additive effect of major genes was 19.84,the additive effect of polygene was 4.3,which means the additive effect of major genes play a more important role in the population;The heritability value of the major genes reached to 91.79%,which significantly higher than that of the polygene,indicated that the heritability of major genes accounted for the major part of the genetic system in height trait.2.Through the results of 3 different hormones concentration gradient,there are different effects of the hormones,there are no significant differences made by any applied levels of IAA and BR,but the proper exogenous GA3(60mg/L)applied could significantly rescued the hypocotyls elongation of E5041,and GA3(80mg/L)forNY18.So we thought E5041 is likely the gibberellin mutant.3.The results of endogenous hormone and measurements dynamic plant height records showed that the endogenous hormoneofGA3in E5041 is significantly higher than NY18,and plant height in the group with GA3 of both E5041 and NY 18 was much higher than the control group.Therefore we speculated that the pathway ofGA3in E5041 may be no problem.However the reason for the height of E5041 with GA3 far from reaching the height of wild NY18 was not clear yet.4.After studying the analysis of DGE results,we knew that:the significant differentially expressed genes of E5041 and NY18 was 7227,3927 up-regulated genes and 3300 down-regulated genes.GO enrichment analysis showed that the enrichment terms of E5041 and NY 18 were 2400,and 383 GO terms were differentially regulated genes,8 were lowered significantly.Nine of anylase activity was significantly down-regulated genes,and the a-amylase activity was capable of inducing the expression of gibberellins,promoting higher plants.And this is same to the result of the Pathway enrichment analysis.It showed that abnormal expression of amylase activity is likely to affect the height of E5041.As homologous genes which encoded DELLA proteins,BnaC09g40420D was significantly up regulated in the E5041,which is likely related to the dwarf mutant E5041. |
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