| Due to the impact of industrial development and human social activities,the area of secondary saline-alkali land is expanding,which seriously threatens the yield and quality of grain.Cultivating and planting salt-tolerant varieties is currently the most economical and effective measure to alleviate land salinization.In this study,a series of strains with salt tolerance were selected from the wheat-Thinopyrum introgression lines cultivated by the laboratory through the identification of salt tolerance at the seedling stage.And one of the strains-CH7034 and salt-sensitive variety SY95-71 were used to construct a population.Their recombinant inbred lines（RILs）were used as the mapping population to map the salt-tolerant QTL at the seedling stage.In addition,salt stress response members of ERF family were discovered based on CH7034 and SY95-71.This study provides a new source of resistance and molecular basis for cultivating salt-tolerant wheat varieties.1.The control salt-tolerant variety Hanxuan 12 and the salt-sensitive variety China Spring（CS）were treated with 200 mmol·L-1,300 mmol·L-1,400mmol·L-1,500 mmol·L-1Na Cl solution,and the leaf salt damage was used as an indicator for wheat seedling tolerance.The result shows the 300 mmol·L-1Na Cl solution is the best salt concentration for germplasm screening.Subsequently,184 wheat-Thinopyrum introgression lines,created by laboratory were identified for salt tolerance.Among them,zero,nine,83,89,and three lines belong to high tolerance,salt tolerance,medium tolerance,sensitivity and high sensitivity,accounting for 0,4.89%,45.11%,48.37%and1.63%,respectively.The salt tolerance of six wheat-Thinopyrum introgression lines,including CH9763,CH3286,CH1696,CH7034,CH1715and CH16425,is higher than Hanxuan 12.At the same time,the salt tolerance of wheat varieties Zhoumai 22,Yannong 999,Jimai 27,Shanrong 3,Chadianhong and AK58 were evaluated.The identification result was:Shanrong 3>Jimai 27>Zhoumai 22>Chadianhong>AK 58>Hanxuan 12>Yannong 999>Chinese Spring.2.CH7034 is one of the six lines selected above with higher salt tolerance than Hanxuan 12.The CH7034 and salt-sensitive wheat variety SY95-71 were tested for salt tolerance in different concentrations of Na Cl solution at the seedling stage.The results showed that the salt tolerance phenotype had the most difference under the stress of 250 mmol·L-1Na Cl;The root tip ion flow rate measurement experiment confirmed that there are significant differences in Na+and K+uptake and excretion of CH7034 and SY95-71.RILs of CH7034 and SY95-71 were used to identify the salt-tolerant phenotypes treated by 250 mmol·L-1Na Cl.Combining with SNP chip scanning data,one stable salt-tolerant site QKna.sx＿5A was mapped on chromosome 5AL,with phenotypic interpretation rates range from 15.73%to20.18%.It was finally located between the marker Kna-5A5845 and Kna-5A5950 by maker encryption,and its physical distance is 10.5 Mb.3.Ethylene response factor（ERF）plays an important role in the process of plants resisting salt stress.In this study,AP2/ERF superfamily was isolated from wheat whole genome.And then,96 ERF family members,a total of 229homologous sequences in A,B and D genomes,were identified from the AP2/ERF superfamily according to the clustering results and structural characteristics.By phylogenetic analysis and database-based transcriptomic analysis,13 Ta ERF members were selected,which displayed high similarity with the cloned salt-tolerant ERF genes or were induced by Na Cl.Subsequently,salt-tolerant material CH7034 and salt-sensitive variety SY95-71 were used to verify the expression levels of the 13 Ta ERFs treated with 250 mmol·L-1Na Cl.The results showed that Ta ERF27,Ta ERF35,Ta ERF55 and Ta ERF64 were significantly up-regulated under Na Cl stress in CH7034,while there was no significant change in SY95-71,speculating that the four genes may be salt stress response genes.Analysis results of tissue specific expression showed that Ta ERF27,Ta ERF35,Ta ERF55 and Ta ERF64expressed highly in seedling root and leaf of CH7034. |
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