Investigation, Molecular Identification And Evolutionary Analysis Of ETR1Sequence In Braya Humilis (Brassicaceae) Plant Resources

Braya humilis, a widespread Cruciferous plant in the northern arid regions of China,was chosen as a model to address the questions. It is same family with the model plantArabidopsis, which has been relatively clear whether. Research and utilization is a problemworthy of attention at Braya humilis by Arabidopsis thaliana.Based on actual field survey and preliminary experiment on drought stress physiology,It found a strong drought resistance ability, high ecological plasticity and great researchpotential in the plant tolerance use. A ethylene receptor genes as the background, combinedwith the traditional software to analysis drought adaptation mechanism in the North Chinafor development and utilization of resources. For increasing desertification, rational use andprotection of the vegetation resources provide important reference and a great significance..The main findings are as follows:1. Combined with database data and related articles,17samples were collected to clearand definite the distribution situation and the characteristics of adaptation.8samples werecollected in different places of Gansu province, which place is JingTai, Lao Hutai, CuiLiugou, LanShan, Jiao Dahoushan, Bai Hushan and HongGu. LanShan group is also dividedinto A and B. Datong in Shanxi Province has sparse distribution and YuLin in Shaanxiprovence, Ordos and BaoTou in Inner Mongolia found no distribution of Braya humilis.2. ITS sequence were obtained644bp long by PCR in Braya humilis. The nucleotidesimiliarities were94％with ITS sequence in NCBI,it proved that the sequence is ITS inBraya humilis,which named BH0087. Furthermore, phylogenetic analysis revealed thatBH0087is higher similar with Braya humilis(21)and Neotorularia brachycarpa(1).3. In order to elucidate the evolutionary characteristics of Braya humilis (C.A. Mey.) B.L. Robins., a pair of universal primers for Ethylene Receptor1(ETR1) gene in Brassicaceaewas chose to amplify the homologous ETR1in Braya humilis by PCR, and14homologoussequences were cloned. Sequences were aligned by Bioedit and the similarities amongthese clonings at nucleotide level were from93％to98％, and the similarities among theseprotein sequences were78%. Nucleotide diversity was measured by DnaSP v5, and14DNAhaplotypes were obtained in1644-1661bp fragments of BhETR1in Braya humilis. Furthermore, phylogenetic analysis revealed that14clonings were classed into three clades,one representative clone from each clade (cloning2, cloning29, and cloning35) was choseto blast with ETR1genes from Arabidopsis thaliana (L.) Heynh and Arabidopsis lyratasubsp, the nucleotide similiarities were both78％. These results suggests that BhETR1is aETR1-like gene, and the high heterogeneity among14BhETR1sequences might be causedby the complex genome of Braya humilis.