| In this study,43 Elytrigia repens germplasms were used as experimental materials,and the salt tolerance of seedlings was identified by progressive salt addition method.For the preliminary screening,the physiological response of 4 salt-tolerant and salts sensitive materials was determined under 180 mmol·L-1 NaCl stress,and the physiological responses difference of the two types of germplasm to salt stress was illuminated.Based on this,E36 and E42 with different salt tolerance were used as experimental materials,and treated with 180 mmol·L-1 NaCl for 0 h and 3 d.The leaves were performed to transcriptome sequencing of Elytrigia repens and investigated the differences in transcriptional expression between the two materials under salt stress,from the combination of physiology and transcription,the salt-tolerant physiology and molecular mechanism of Elytrigia repens were discussed,which laid a foundation for the salt tolerance research of Elytrigia repens.The main results were as follows:(1)The scores of salt tolerance 43 germplasms were determined by progressive salt addition method.The analysis of variance showed that there were significant differences among the germplasm scores,among which the E36 score was the lowest and the E28,E30 and E42 scores were higher.It was observed that the physiological responses of the germplasm at 0,5 and 10 days under 180 mmol·L-1 NaCl stress,the relative water content,K+/Na+ and chlorophyll content of E36 were significantly decreased under salt stress,and the activity of oxidative metabolic enzyme was maintained.At the lower level,it showed significant damage;under salt stress,E42 proline accumulated significantly,oxidative metabolic enzyme activity increased to varying degrees,while relative water content and conductivity did not change significantly,showing better salt tolerance,E28,E30 salt tolerance is medium.(2)Using E36(salt sensitive)and E42(salt-tolerant)as materials,and the stress was incubated with 180 mmol·L-1 NaCl.The transcriptome sequencing of the leaves at 3 h and 0 d under salt stress showed that 80 735 Unigenes were obtained by sequencing,of which 64.55%were obtained of Unigenes were successfully annotated.The homology alignment found the highest homology with the knotted wheat,and the homology was 20.92%.The differentially expressed genes were compared,and the E42 salt treatment showed 0 d and 3 d comparisons and found that plant pathogen interaction,starch and Sucrose metabolism and phenylpropanoid biosynthesis were significantly enriched.E36 salt treatment showed significant enrichment in ribosome metabolism,linoleic acid metabolism and carbon metabolism at 0 d and 3 d.Compared with metabolic pathways,E36 and E42 were photoreactive There are significant differences in the light-harvesting protein pathway,with significant differences in LHCbl(Light-harvesting complex II,LHCb).(3)Comparing Unigenes for 0 d and 3 d under salt treatment of E42,159 differentially expressed genes related to salt tolerance were obtained,and 46 transcription factors were extracted.Under the same treatment with E36 salt,61 genes related to salt tolerance were obtained,15 transcription factors were excavated,And 26 genes have differential expression in both comparisons.And there were significant differences in the expression of WRKY transcription factors and peroxidase metabolism related genes under salt stress of E36 and E42.(4)Using the real-time fluorescent quantitative PCR method,and Actin as the internal reference gene,qRT-PCR was performed on 6 genes that may be related to salt tolerance and significantly different.The results of significantly expressed genes were verified by qRT-PCR to be consistent with the transcriptome data.In summary,photosynthetic regulation,proline and peroxide metabolism of Elytrigia repens showed significant differences in physiological response and transcriptomics.This difference could be one of the important factors leading to salt tolerance between the tested materials of Elytrigia repens. |
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