| The saline-alkali soil in Songnen Plain was above pH 9.2. The investigation about the distribution of plant resources had found about 184 genera and 51 families halopHytes, herb occupied the most dominant groups. Salix is the only community distribution of woody plants. Salix has not only a stronger tolerant saline-alkali stress ability, but plays an important role in maintaining ecological balance and soil improvement.In this paper, Salix as experimental material was analyzed the stress resistance and pHysiological characteristics. FOX hunting system technology was used to transform Salix cDNA into yeast and Arabidopsis. The resistance of transgenic yeast was analyzed under NaCl stress and transgenic Arabidopsis lines were constructed. NaCl as stress factors Salix were doing RNA-Seq on the treated and untreated groups, to obtain two sets of Salix transcriptome data.This study is as follows:1. Salix linearistipularis Resources:The germination rate and root length of Salix were analyzed under NaCl, Sorbitol, NaHC03, H2O2 and different pH values. The results showed that Salix can grow in high stress condition, and the soluble sugar and proline content were significantly increase under different stress treatments. These results showed Salix is strong stress tolerant woody plants in saline-alkali soil.2. Screened at the level of yeast:15 tolerant salt strains were isolated from yeast cDNA library. These gene sequences had higher similarity with Populus trichocarpa, some of which genes had metallothionein-like protein MT2, Casein kinase Ⅲ (CK Ⅱ) and plasma membrane intrinsic protein (PIP)3. Construction of independent transgenic Arabidopsis lines:The Salix cDNA library using Agrobacterium infestation was transformed into Arabidopsis, and had obtained over 9000 trangenic Arabidopsis plants. The pHenotype changes (leaf size, plant height, branch number, plant lodging, bolting, pod length, leaf number and leaf shape change) of 28 (0.35%) plants had significant with the wild-type.58 seedlings were screened by the 1/2MS with 130 mM NaCl stress resistance. By sequencing and sequence alignment, one gene had high similarity with COP9 complex family protein of Populus trichocarpa and the other gene had high similarity with SAPK7 Serine-threonine protein kinase of Triticum urartu. These genes were related with hypertonic salt, oxidation and other abiotic stresses.4. Functional verification of S1MT2 gene:Six transgenic plants were identified by isolating MT2 gene from yeast cDNA library. The results performed that the transgenic Arabidopsis exhibited a stronger resistance than the control in NaCl, NaHCO3, H2O2, CuCl2, ZnCl2, CdCl2 and sorbitol stresses, and overexpressor showed more stronger resistance than WT plants in CdCl2 stress.5. Transcriptomics analysis of Salix linearistipularis:There were 1397 up-regulated genes and 1637 down-regulated genes obtained by the transcription profiles analysis under salt shtess.2199 genes were classified into 50 GO terms and 1103 genes were 116 biological pathways. All-unigenes of salix linearistipularis were classified into 3 categories according to their degree of the differentially expressed genes (DEGs) at 0-1.5 folds,1.5-4.0 and more than 4.0. The pathways of 3 categorized genes were compared with the related pathways of arabidopsis thaliana, showing that 22,10 and 1 pathways of salix linearistipularis were overlapped with arabidopsis thaliana for 0-1.5 folds, 1.5-4.0 folds and more than 4.0 folds category, respectively.Genetic profiles of salix linearistipularis were established in this work. Therefore, some salt tolerance mechanisms of salix linearistipularis were pre-developed by long exposure to drought and salt stress, that some salt-resistance genes of salix linearistipularis played a constitutive nature role. |
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