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Transcriptome Analysis Of Brassica Parachinensis L.under Cadmium Stress

Posted on:2019-09-01Degree:MasterType:Thesis
Country:ChinaCandidate:W X ZhangFull Text:PDF
GTID:2370330566461473Subject:Biology
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Chinese flowering cabbage(Brassica parachinensis L.),is one of the most important vegetables,and there is a large area planted in southern China.Compared to the other crops,chinese flowering cabbage tend to accumulate cadmium(Cd),however soil Cd pollution is most serious in southern China.Cd not only leads to reduce crop yield but also threats to human health through food chain.Comsuming food,over criteria of Cd,in long term will increase the risk of lung cancer,renal failure,osteoporosis,and so on.Therefore Chinese flowering cabbage breeding require not only high-yield varieties,good quality and stress resistance but also low-accumulation of Cd.The analysis of the molecular mechanism of response to Cd,Cd uptake and translocation in Chinese flowering cabbage,which will provide an idea for screening or breeding low-accumulation Cd cultivars.The seed germination was to conduct to investigate the effect of Cd on seed germination and root length under CK(no add Cd)and Cd(50?mol/L Cd(NO3)2)treatment.The results were below.Of all cultivars,the germination potential enhanced,the seed germination didn't inhibited under Cd exposure.According to the result of root length indicate the cultivars YQ49?LB70T and YL702's root development are depressed,and there were no significant differences in other cultivars.To investigate the influence of Cd on biomass of chinese flowering cabbage seedling,the result is as follows: the cultivars 80 TYQ,GL19,JY40 had significantly lower shoot biomass and only the cultivar YQ49 had a significantly higher root biomass under the Cd treatment when compared with that under CK(p value<0.05).And others cultivar had similar shoot and root biomass to CK(without significant difference),indicated that difference cadmium tolerance between different cultivars,which might have different mechanisms to response cadmium stress.Besides all cultivars had no significant difference concentration of cadmium.The shoot and root of Chinese flowering cabbage were harvested at 0h and 48 h exposed to Cd,the totol RNA was extracted which used to construct four libraries,CK-L,CK-R,48H-L,48H-R,respectively.The transcriptome of among the libraries were acquired,and after date processing the differential expression genes(DEGs)were acquired.The differential expression genes were annotated and enrichment analysis in GO and KEGG,and the results were below.The predominant enriched GO terms of up regulate DEGs were involved oxidoreductase activity,toxin catabolic process,transporter activity,regulation of cell death,suberin biosynthetic process,salicylic acid biosynthetic process and etc.The predominant enriched GO terms of down regulate DEGs were including photosynthesis,DNA replication initiation,mitotic cytokinetic process,cell wall,microtubule and etc.In the lignin metabolism term,there were genes related to lignin synthesis,such as LAC4,LAC11,LAC17,etc.,indicating that lignin synthesis might be affected under cadmium stress.In the metal ion transport term,there were HMA2,ZIP family genes,Nramp4 and other genes,which expression were up regulated under cadmium stress,indicating that these genes might be related to the absorption and transport of cadmium.The predominant enriched KEGG Pathways of DEGs were involved Glucosinolate biosynthesis,Cutin,suberine and wax biosynthesis,Photosynthesis,MAPK signaling pathway-plant,Sulfur metabolism and so on.The GO terms and KEGG pathways,the above mentioned,might be response to cadmium stress.The gene family,which has been reported to be related to cadmium transport,was selected as a q PCR validation gene,such as HMA2,MRP7,ABCG40,NRAMP1,YSL2 and so on,and these genes were annotated to the metal ion transport(GO:0030001)in the GO database.The DEGs were verified by q PCR,which the results correlated with the transcriptome analysis,indicating that the transcriptome analysis was reliable.Nramp family genes,play an important role in the absorption and accumulation of cadmium in arabidopsis and rice.Analyzing of At Nramp and Os Nramp sequence and comparing with transcriptome date,three homologous genes were Bra000573,Bra008437,Bra012154 found respectively,also complete the cloning.Bra008437 and Bra012154 were up regulate DEGs,it might play a role in cadmium absorption and accumulation in flowering Chinese Cabbage.In addition,this study will broaden the understanding of plant response to cadmium stress,and provide a theoretical basis for screening and breeding of cadmium absorptionand accumulation of small cabbage varieties.
Keywords/Search Tags:Brassica parachinensis L, Cadmium, Transcriptome, Nramp
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