Study On Chloroplast Functional Genomics Of Some Popular Species In Limonium Mill

Limonium Mill belongs to salt secreting halophytes.The study of chloroplast genome is of great significance to the system development of such plants and the molecular genetic mechanism related to salt stress.In this study,3 species,Limonium sinense(Girard)Kuntze,Limonium bicolor(Bunge)Kuntze,Limonium franchetii Kuntze were collected from Huangbohai coastal beach area,and 2 species,Limonium gmelinii(Willd)Kuntze and Limonium aureum(Linn)Hill was collected from Xinjiang and Qinghai region.The first two species were not easily distinguishable in morphology,and the distribution areas of the model specimens were also very similar.Therefore,they were compared with Limonium franchetii Kuntze,Limonium aureum(Linn)whitch collected from the same region while having marked,differences in morphology,and with Limonium gmelinii(Willd)Kuntze collected in different regions as a control.In order to determine the phylogenetic and evolutionary relationship between these species,molecular biology technology was used to identify and analyze their gene structure and characteristics of chloroplast genome.The study of chloroplast gene function also plays an important role in understanding the function of chloroplast coding genes in stress response and photosynthesis.The main results are as follows:1.The phylogenetic analysis of five Limonium Mill species.The system adjacent to the tree establishment using DNA barcoding technology,based on the nuclear gene ITS,chloroplast gene psbA-trnH and trnL-trnF showed that among Limonium sinense,Limonium franchetii,Limonium gmelinii,Limonium aureum,bicolor and the three local samples(1,2 and 3),Limonium gmelinii had remarkbale sequence differences from other seven samples,and could be distinquished with three pairs of primers.The interspecific differences between other seven samples were little and could not be distinquished using the three pairs of primers for ITS,psbA-trnH and trnL–trnF.Their system evolutionary relationships could not be analysised either.2.High through-put sequencing and chloroplast genome composition,structure and function analysis of five Limonium Mill species.The chloroplast genome DNA of Limonium sinensis was extracted and purified using high-salt low pH system.After whole chloroplast genome sequencing,five chloroplast genome sequences of Limonium Mill were successfully obtained,and the chloroplast genome composition of Limonium sinense was classified.In comparing the chloroplast genomes of five Limonium Mill species,66 of shared protein genes were identified.The evolutionary relationships of five Limonium Mill species were studied through comparison of these shared genes.3.Investigation of molecular mechanisms for salt tolerance and drought resistance in five Limonium Mill species.qRT-PCR technique was used to analyze the expression levels of atpA,psaA,psbA,petA,ndhA,POD,APX,and NHX1 genes in 5 Limonium Mill species under 200 mmol/L NaCl salt stress or 20% PEG-6000 simulated drought stress,respectively.Preliminary investigation on the mechanism of salt and drought resistance of Limonium Mill at the molecular level...