| In recent years,with the rise of rural tourism,oilseed Brassica is not only used for oil,honey,vegetables,and so on,but also increased the ornamental function.Therefore,it is very important to enrich the color of oilseed Brassica and explore the synthesis and regulation of pigment such as anthocyanin in Brassica.At present,the research on anthocyanin of Brassica napus mainly focuses on petals and purple leaves of different colors,but the research on purple stems is rare.Anthocyanin,as an important pigment in plants,can not only make plant tissues colorful,but also plays a role in resistance to adversity stress in plants.In this paper,the differences of anthocyanin content and types in different parts of the purple stem of Brassica napus as well as the expression of genes related to the regulation of anthocyanin synthesis were investigated,and the physiological and ecological changes of the white flower purple stem B.napus and the white flower green stem B.napus under the simulated drought by PEG were compared.The main research results are as follows:1.The accumulation characteristics of anthocyanin in B.napus were investigated.The tissue accumulation characteristics of anthocyanin were determined by microscopic observation of stem section.Using LC-MS/MS technology to identify the various kinds of anthocyanins,we successfully identified six major types of anthocyanins in purple stem rape: Cyanidin-3-sophoroside(Sinapyl)-5-glucoside,Petunidin-3-glucoside-5-glucoside,Cyanidin-3-sophoroside(p-Comaroyl)-5-glucoside,Cyanidin-3-glucoside(Malonyl)-5-glucoside(Sinapyl)-7-glucoside,Cyanidin-3-sophoroside(Ferulic-acid)-5-glucoside(Malonyl),and Cyanidin-3-sophoroside(Sinapyl-p-Comaroyl)-5-glucoside(Malonyl).The content of anthocyanin in the tissues of cornflower,stem and leaf was determined by high performance liquid chromatography(HPLC)with the standard of cornflower3-o-glucose as the standard sample,which were 2.41 g/mg,0.92 g/mg and 0.25 g/mg,respectively.2.The stability of anthocyanin extraction solution and the expression of anthocyanin related genes of B.napus were studied.The storage rate of anthocyanin at different temperatures and pH values was determined.As the pH changes from acidic to alkaline,the retention rate of anthocyanin decreases,and the appearance changes from red to bluish purple.It was proved that low temperature and acid conditions were more favorable for anthocyanin storage.The biochemical and molecular basis of anthocyanin phenotype was studied,and the relative expression levels of anthocyanin synthesis regulating genes in purple stem rapeseed were measured by taking stem,leaf and pod of green stem B.napus as control.The results showed that the expression of anthocyanin-related genes in different parts of purple stem B.napus was significantly different from that in green stem B.napus.The expression levels of structural genes such as ANS,UGT79B1,DFR,MT and regulatory genes such as PAP1 and TT19 were mainly increased in stem,but the expression levels of most other genes were decreased compared with that in green stem.MT,DFR and other structural genes were dominant in the leaves,while the relative expression of most of the other genes was not significantly increased.The expression of MYB113 was the most obvious regulator gene.3.The differences of growth and physiology and biochemistry between purple stem B.napus and green stem B.napus under 10% PEG simulated drought stress were studied.PEG simulated drought treatment inhibited the germination of Brassica seeds and reduced the biomass,and certain concentration of PEG could promote the growth of rape radicle.At the same time,drought treatment also inhibited the growth of Brassica seedlings,the photosynthetic activity of rape decreased obviously,the accumulation of ROS increased,the activities of SOD,POD and APX increased obviously,and the water content of leaves decreased,proline,soluble sugar,leaf conductivity and other osmotic adjustment substances increased significantly.On the whole,the drought adaptability of purple stem B.napus was better than that of green stem B.napus,which may be due to the antioxidant effect of anthocyanins in purple stem B.napus under stress.The expression of antioxidation-related genes and anthocyanin synthesis related genes in purple and green stem Brassica under PEG simulated drought conditions were studied.After drought stress,the expression levels of antioxidant enzyme related genes such as SOD,POD and APX increased to different degrees,and anthocyanin synthesis related genes such as MYB113,DFR and UGT79B1 also increased to different degrees,compared with the two types of stem color of Brassica under normal environment.Violet bine Brassica of antioxidant enzyme gene and anthocyanin increased the expression of related genes degree is greater than the green stem Brassica,suggesting that under drought treatment PEG,purple stems Brassica has better antioxidant ability to adapt,and drought stress can induce the expression of anthocyanin synthesis related genes,promote plant synthesis and accumulation of anthocyanin. |
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